X-ray diffraction and Raman study of DL-alanine at high pressure: revision of phase transitions

The effect of pressure on DL-alanine has been studied by X-ray powder diffraction (up to 8.3 GPa), single-crystal X-ray diffraction and Raman spectroscopy (up to ∼ 6 GPa). No structural phase transitions have been observed. At ∼ 1.5–2 GPa, cell parameters b and c become accidentally equal to each other, but the space-group symmetry does not change. There is no phase transition between 1.7 and 2.3 GPa, contrary to what has been reported earlier [Belo et al. (2010). Vibr. Spectrosc. 54, 107–111]. The presence of the second phase transition, which was claimed to appear within the pressure range from 6.0 to 7.3 GPa (Belo et al., 2010), is also argued. The changes in the Raman spectra have been shown to be continuous in all the pressure ranges studied.

Computing details

For all compounds, data collection: CrysAlis PRO (Oxford Diffraction Ltd, 2010); cell refinement: CrysAlis PRO (Oxford Diffraction Ltd, 2010); data reduction: CrysAlis PRO (Oxford Diffraction Ltd, 2010); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: Mercury (Macrae et al., 2008); software used to prepare material for publication: Mercury (Macrae et al., 2008), PLATON (Spek, 2009), enCIFer (Allen et al., 2004).

(dlala_01kbar) DL-2-Aminopropionic Acid

Crystal data

C3H7NO2	F(000) = 192
Mr = 89.10	Dx = 1.405 Mg m^−3
Orthorhombic, Pna21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2n	Cell parameters from 1621 reflections
a = 11.994 (2) Å	θ = 3.5–31.1°
b = 6.0103 (16) Å	µ = 0.12 mm^−1
c = 5.8421 (5) Å	T = 293 K
V = 421.13 (15) Å^3	Plate, colorless
Z = 4	0.16 × 0.10 × 0.06 mm

Data collection

Oxford Diffraction Gemini Ultra R diffractometer	647 independent reflections
Graphite monochromator	487 reflections with I > 2σ(I)
Detector resolution: 10.3457 pixels mm^-1	Rint = 0.068
ω scans	θmax = 31.1°, θmin = 3.8°
Absorption correction: gaussian Absorb6.1 (R. J. Angel, 2004)	h = −14→14
Tmin = 0.399, Tmax = 0.478	k = −6→6
3719 measured reflections	l = −8→8

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.040	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.077	H-atom parameters constrained
S = 1.03	w = 1/[σ^2(Fo^2) + (0.0342P)^2] where P = (Fo^2 + 2Fc^2)/3
647 reflections	(Δ/σ)max < 0.001
57 parameters	Δρmax = 0.11 e Å^−3
1 restraint	Δρmin = −0.11 e Å^−3

Special details

Experimental. high pressure measurement at 0.1 GPa in the DAC

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O2	0.58853 (18)	0.4838 (4)	0.6042 (3)	0.0391 (6)
O1	0.68638 (15)	0.1986 (3)	0.7406 (2)	0.0367 (5)
C1	0.6455 (2)	0.3131 (6)	0.5815 (4)	0.0296 (7)
C2	0.6631 (2)	0.2183 (5)	0.3386 (3)	0.0255 (7)
H2	0.7415	0.1748	0.3234	0.031*
C3	0.5926 (3)	0.0190 (6)	0.2930 (4)	0.0404 (9)
H3B	0.6061	−0.0333	0.1402	0.048*
H3C	0.5154	0.0581	0.3089	0.048*
H3A	0.6108	−0.0962	0.4004	0.048*
N1	0.63912 (17)	0.3948 (4)	0.1656 (3)	0.0292 (6)
H1C	0.6846	0.5098	0.1881	0.035*
H1B	0.5687	0.4395	0.1799	0.035*
H1A	0.6497	0.3404	0.0256	0.035*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O2	0.0394 (16)	0.0505 (19)	0.0275 (10)	0.0171 (9)	0.0046 (10)	−0.0049 (8)
O1	0.0435 (15)	0.048 (2)	0.0181 (6)	0.0061 (9)	−0.0017 (9)	0.0025 (10)
C1	0.021 (2)	0.050 (3)	0.0175 (10)	−0.0019 (11)	0.0025 (10)	−0.0028 (13)
C2	0.028 (2)	0.031 (3)	0.0173 (10)	0.0026 (10)	−0.0016 (10)	−0.0004 (12)
C3	0.049 (3)	0.047 (3)	0.0252 (15)	−0.0054 (13)	0.0008 (12)	−0.0016 (14)
N1	0.0302 (15)	0.038 (2)	0.0188 (8)	0.0001 (9)	−0.0010 (8)	0.0011 (9)

Geometric parameters (Å, º)

O2—C1	1.240 (4)	C3—H3B	0.9600
O1—C1	1.256 (3)	C3—H3C	0.9600
C1—C2	1.544 (3)	C3—H3A	0.9600
C2—C3	1.491 (4)	N1—H1C	0.8900
C2—N1	1.493 (3)	N1—H1B	0.8900
C2—H2	0.9800	N1—H1A	0.8900
O2—C1—O1	126.1 (2)	H3B—C3—H3C	109.5
O2—C1—C2	118.6 (2)	C2—C3—H3A	109.5
O1—C1—C2	115.1 (2)	H3B—C3—H3A	109.5
C3—C2—N1	109.9 (2)	H3C—C3—H3A	109.5
C3—C2—C1	112.5 (2)	C2—N1—H1C	109.5
N1—C2—C1	109.5 (2)	C2—N1—H1B	109.5
C3—C2—H2	108.3	H1C—N1—H1B	109.5
N1—C2—H2	108.3	C2—N1—H1A	109.5
C1—C2—H2	108.3	H1C—N1—H1A	109.5
C2—C3—H3B	109.5	H1B—N1—H1A	109.5
C2—C3—H3C	109.5
O2—C1—C2—C3	−103.4 (4)	O2—C1—C2—N1	19.1 (4)
O1—C1—C2—C3	72.7 (4)	O1—C1—C2—N1	−164.8 (2)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1B···O2^i	0.89	1.99	2.849 (3)	161
N1—H1A···O1^ii	0.89	1.92	2.806 (2)	173
N1—H1A···O2^ii	0.89	2.71	3.378 (3)	133
N1—H1C···O1^iii	0.89	1.94	2.812 (2)	165

Symmetry codes: (i) −x+1, −y+1, z−1/2; (ii) x, y, z−1; (iii) −x+3/2, y+1/2, z−1/2.

(dlala_05kbar) DL-2-Aminopropionic Acid

Crystal data

C3H7NO2	F(000) = 192
Mr = 89.10	Dx = 1.430 Mg m^−3
Orthorhombic, Pna21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2n	Cell parameters from 1631 reflections
a = 11.938 (3) Å	θ = 3.5–30.8°
b = 5.9485 (18) Å	µ = 0.12 mm^−1
c = 5.8266 (6) Å	T = 293 K
V = 413.75 (16) Å^3	Plate, colorless
Z = 4	0.16 × 0.10 × 0.06 mm

Data collection

Oxford Diffraction Gemini Ultra R diffractometer	640 independent reflections
Graphite monochromator	502 reflections with I > 2σ(I)
Detector resolution: 10.3457 pixels mm^-1	Rint = 0.062
ω scans	θmax = 30.9°, θmin = 3.8°
Absorption correction: gaussian Absorb6.1 (R. J. Angel, 2004)	h = −14→14
Tmin = 0.397, Tmax = 0.478	k = −6→6
3677 measured reflections	l = −8→8

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.042	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.081	H-atom parameters constrained
S = 1.05	w = 1/[σ^2(Fo^2) + (0.0383P)^2] where P = (Fo^2 + 2Fc^2)/3
640 reflections	(Δ/σ)max < 0.001
57 parameters	Δρmax = 0.14 e Å^−3
1 restraint	Δρmin = −0.13 e Å^−3

Special details

Experimental. high pressure measurement at 0.5 GPa in the DAC

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O2	0.58918 (17)	0.4838 (4)	0.6039 (3)	0.0362 (6)
O1	0.68546 (15)	0.1925 (3)	0.7414 (3)	0.0348 (5)
C1	0.6444 (2)	0.3079 (6)	0.5812 (4)	0.0280 (7)
C2	0.6633 (2)	0.2129 (5)	0.3384 (3)	0.0236 (7)
H2	0.7421	0.1689	0.3237	0.028*
C3	0.5914 (2)	0.0099 (6)	0.2937 (5)	0.0375 (9)
H3B	0.6065	−0.0468	0.1426	0.045*
H3C	0.5138	0.0512	0.3047	0.045*
H3A	0.6078	−0.1042	0.4052	0.045*
N1	0.63875 (17)	0.3898 (4)	0.1647 (3)	0.0272 (5)
H1C	0.6837	0.5071	0.1876	0.033*
H1B	0.5677	0.4332	0.1780	0.033*
H1A	0.6502	0.3347	0.0246	0.033*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O2	0.0392 (15)	0.0419 (18)	0.0276 (11)	0.0159 (9)	0.0034 (9)	−0.0047 (8)
O1	0.0432 (15)	0.0423 (19)	0.0189 (7)	0.0063 (8)	−0.0001 (9)	0.0026 (10)
C1	0.020 (2)	0.044 (3)	0.0196 (11)	−0.0034 (11)	0.0008 (10)	−0.0036 (13)
C2	0.023 (2)	0.030 (3)	0.0174 (11)	0.0029 (10)	−0.0005 (9)	−0.0003 (12)
C3	0.048 (3)	0.042 (3)	0.0229 (15)	−0.0027 (12)	−0.0001 (12)	−0.0016 (13)
N1	0.0290 (14)	0.034 (2)	0.0185 (8)	−0.0013 (9)	−0.0001 (8)	0.0013 (9)

Geometric parameters (Å, º)

O2—C1	1.244 (4)	C3—H3B	0.9600
O1—C1	1.258 (3)	C3—H3C	0.9600
C1—C2	1.540 (3)	C3—H3A	0.9600
C2—N1	1.489 (3)	N1—H1C	0.8900
C2—C3	1.504 (4)	N1—H1B	0.8900
C2—H2	0.9800	N1—H1A	0.8900
O2—C1—O1	125.9 (2)	H3B—C3—H3C	109.5
O2—C1—C2	118.9 (2)	C2—C3—H3A	109.5
O1—C1—C2	115.1 (2)	H3B—C3—H3A	109.5
N1—C2—C3	109.7 (2)	H3C—C3—H3A	109.5
N1—C2—C1	109.7 (2)	C2—N1—H1C	109.5
C3—C2—C1	111.7 (2)	C2—N1—H1B	109.5
N1—C2—H2	108.6	H1C—N1—H1B	109.5
C3—C2—H2	108.6	C2—N1—H1A	109.5
C1—C2—H2	108.6	H1C—N1—H1A	109.5
C2—C3—H3B	109.5	H1B—N1—H1A	109.5
C2—C3—H3C	109.5
O2—C1—C2—N1	16.8 (4)	O2—C1—C2—C3	−105.1 (4)
O1—C1—C2—N1	−165.1 (2)	O1—C1—C2—C3	73.1 (4)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1B···O2^i	0.89	1.98	2.845 (3)	162
N1—H1A···O1^ii	0.89	1.90	2.788 (2)	174
N1—H1A···O2^ii	0.89	2.71	3.368 (3)	132
N1—H1C···O1^iii	0.89	1.94	2.801 (2)	163

Symmetry codes: (i) −x+1, −y+1, z−1/2; (ii) x, y, z−1; (iii) −x+3/2, y+1/2, z−1/2.

(dlala_10kbar) DL-2-Aminopropionic Acid

Crystal data

C3H7NO2	F(000) = 192
Mr = 89.10	Dx = 1.465 Mg m^−3
Orthorhombic, Pna21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2n	Cell parameters from 1471 reflections
a = 11.852 (2) Å	θ = 3.5–30.9°
b = 5.8715 (14) Å	µ = 0.12 mm^−1
c = 5.8057 (5) Å	T = 293 K
V = 404.02 (12) Å^3	Plate, colorless
Z = 4	0.16 × 0.10 × 0.06 mm

Data collection

Oxford Diffraction Gemini Ultra R diffractometer	607 independent reflections
Graphite monochromator	472 reflections with I > 2σ(I)
Detector resolution: 10.3457 pixels mm^-1	Rint = 0.060
ω scans	θmax = 31.0°, θmin = 3.9°
Absorption correction: gaussian Absorb6.1 (R. J. Angel, 2004)	h = −13→13
Tmin = 0.406, Tmax = 0.478	k = −6→6
3497 measured reflections	l = −8→8

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.039	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.069	H-atom parameters constrained
S = 1.02	w = 1/[σ^2(Fo^2) + (0.0291P)^2] where P = (Fo^2 + 2Fc^2)/3
607 reflections	(Δ/σ)max < 0.001
57 parameters	Δρmax = 0.14 e Å^−3
1 restraint	Δρmin = −0.14 e Å^−3

Special details

Experimental. high pressure measurement at 1.0 GPa in the DAC

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O2	0.58909 (17)	0.4840 (4)	0.6036 (3)	0.0351 (6)
O1	0.68502 (16)	0.1863 (3)	0.7419 (2)	0.0346 (5)
C1	0.6447 (2)	0.3069 (6)	0.5812 (4)	0.0272 (7)
C2	0.6630 (2)	0.2073 (6)	0.3378 (3)	0.0226 (7)
H2	0.7423	0.1625	0.3230	0.027*
C3	0.5910 (2)	0.0025 (7)	0.2938 (4)	0.0349 (9)
H3B	0.6086	−0.0594	0.1450	0.042*
H3C	0.5129	0.0456	0.2982	0.042*
H3A	0.6052	−0.1102	0.4100	0.042*
N1	0.63855 (16)	0.3871 (4)	0.1632 (3)	0.0256 (5)
H1C	0.6827	0.5070	0.1886	0.031*
H1B	0.5666	0.4290	0.1741	0.031*
H1A	0.6518	0.3324	0.0228	0.031*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O2	0.0380 (16)	0.042 (2)	0.0256 (10)	0.0148 (9)	0.0030 (9)	−0.0053 (8)
O1	0.0394 (16)	0.047 (2)	0.0168 (6)	0.0077 (9)	0.0000 (9)	0.0028 (10)
C1	0.016 (2)	0.050 (3)	0.0157 (11)	−0.0086 (11)	0.0045 (10)	−0.0021 (14)
C2	0.017 (2)	0.033 (3)	0.0181 (11)	−0.0003 (10)	0.0000 (10)	0.0010 (12)
C3	0.041 (3)	0.040 (3)	0.0231 (15)	−0.0050 (12)	−0.0008 (12)	0.0002 (13)
N1	0.0293 (15)	0.032 (2)	0.0159 (8)	−0.0037 (9)	0.0004 (9)	0.0007 (9)

Geometric parameters (Å, º)

O2—C1	1.238 (4)	C3—H3B	0.9600
O1—C1	1.265 (3)	C3—H3C	0.9600
C1—C2	1.545 (3)	C3—H3A	0.9600
C2—N1	1.492 (3)	N1—H1C	0.8900
C2—C3	1.497 (4)	N1—H1B	0.8900
C2—H2	0.9800	N1—H1A	0.8900
O2—C1—O1	126.4 (2)	H3B—C3—H3C	109.5
O2—C1—C2	119.3 (2)	C2—C3—H3A	109.5
O1—C1—C2	114.2 (2)	H3B—C3—H3A	109.5
N1—C2—C3	110.0 (2)	H3C—C3—H3A	109.5
N1—C2—C1	109.0 (2)	C2—N1—H1C	109.5
C3—C2—C1	112.4 (2)	C2—N1—H1B	109.5
N1—C2—H2	108.5	H1C—N1—H1B	109.5
C3—C2—H2	108.5	C2—N1—H1A	109.5
C1—C2—H2	108.5	H1C—N1—H1A	109.5
C2—C3—H3B	109.5	H1B—N1—H1A	109.5
C2—C3—H3C	109.5
O2—C1—C2—N1	17.6 (4)	O2—C1—C2—C3	−104.6 (4)
O1—C1—C2—N1	−166.0 (2)	O1—C1—C2—C3	71.8 (4)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1B···O2^i	0.89	1.96	2.824 (3)	164
N1—H1A···O1^ii	0.89	1.88	2.770 (2)	174
N1—H1A···O2^ii	0.89	2.70	3.350 (3)	131
N1—H1C···O1^iii	0.89	1.91	2.769 (2)	161

Symmetry codes: (i) −x+1, −y+1, z−1/2; (ii) x, y, z−1; (iii) −x+3/2, y+1/2, z−1/2.

(dlala_15kbar) DL-2-Aminopropionic Acid

Crystal data

C3H7NO2	F(000) = 192
Mr = 89.10	Dx = 1.496 Mg m^−3
Orthorhombic, Pna21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2n	Cell parameters from 1215 reflections
a = 11.7991 (15) Å	θ = 3.9–26.8°
b = 5.7917 (15) Å	µ = 0.13 mm^−1
c = 5.7900 (4) Å	T = 293 K
V = 395.67 (12) Å^3	Plate, colorless
Z = 4	0.16 × 0.10 × 0.06 mm

Data collection

Oxford Diffraction Gemini Ultra R diffractometer	462 independent reflections
Graphite monochromator	385 reflections with I > 2σ(I)
Detector resolution: 10.3457 pixels mm^-1	Rint = 0.056
ω scans	θmax = 26.8°, θmin = 3.9°
Absorption correction: gaussian Absorb6.1 (R. J. Angel, 2004)	h = −13→13
Tmin = 0.417, Tmax = 0.476	k = −5→5
2319 measured reflections	l = −7→7

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.037	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.067	H-atom parameters constrained
S = 1.05	w = 1/[σ^2(Fo^2) + (0.0287P)^2] where P = (Fo^2 + 2Fc^2)/3
462 reflections	(Δ/σ)max < 0.001
57 parameters	Δρmax = 0.13 e Å^−3
1 restraint	Δρmin = −0.14 e Å^−3

Special details

Experimental. high pressure measurement at 1.5 GPa in the DAC

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O2	0.5900 (2)	0.4842 (6)	0.6033 (4)	0.0366 (9)
O1	0.68410 (17)	0.1800 (4)	0.7435 (3)	0.0359 (9)
C1	0.6444 (2)	0.3010 (8)	0.5813 (5)	0.0261 (13)
C2	0.6622 (2)	0.2024 (8)	0.3370 (4)	0.0232 (13)
H2	0.7420	0.1578	0.3213	0.028*
C3	0.5907 (3)	−0.0055 (10)	0.2930 (6)	0.0350 (13)
H3B	0.6080	−0.0668	0.1430	0.042*
H3C	0.5121	0.0369	0.2992	0.042*
H3A	0.6061	−0.1203	0.4084	0.042*
N1	0.63742 (19)	0.3853 (6)	0.1637 (3)	0.0302 (9)
H1C	0.6819	0.5067	0.1895	0.036*
H1B	0.5652	0.4278	0.1755	0.036*
H1A	0.6504	0.3308	0.0224	0.036*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O2	0.0392 (15)	0.042 (3)	0.0285 (15)	0.0104 (11)	0.0007 (11)	−0.0047 (12)
O1	0.0384 (14)	0.053 (3)	0.0161 (8)	0.0082 (12)	−0.0029 (10)	0.0005 (14)
C1	0.016 (2)	0.043 (5)	0.0197 (16)	−0.0063 (14)	0.0033 (13)	−0.001 (2)
C2	0.030 (2)	0.024 (5)	0.0150 (14)	−0.0009 (15)	−0.0018 (11)	0.001 (2)
C3	0.043 (3)	0.042 (5)	0.019 (2)	−0.0054 (17)	−0.0006 (13)	−0.0031 (16)
N1	0.0334 (16)	0.039 (4)	0.0180 (11)	−0.0024 (13)	0.0027 (10)	−0.0030 (16)

Geometric parameters (Å, º)

O2—C1	1.246 (5)	C3—H3B	0.9600
O1—C1	1.262 (4)	C3—H3C	0.9600
C1—C2	1.540 (4)	C3—H3A	0.9600
C2—N1	1.488 (4)	N1—H1C	0.8900
C2—C3	1.492 (6)	N1—H1B	0.8900
C2—H2	0.9800	N1—H1A	0.8900
O2—C1—O1	126.0 (3)	H3B—C3—H3C	109.5
O2—C1—C2	118.7 (3)	C2—C3—H3A	109.5
O1—C1—C2	115.3 (3)	H3B—C3—H3A	109.5
N1—C2—C3	110.4 (3)	H3C—C3—H3A	109.5
N1—C2—C1	109.2 (3)	C2—N1—H1C	109.5
C3—C2—C1	112.3 (3)	C2—N1—H1B	109.5
N1—C2—H2	108.3	H1C—N1—H1B	109.5
C3—C2—H2	108.3	C2—N1—H1A	109.5
C1—C2—H2	108.3	H1C—N1—H1A	109.5
C2—C3—H3B	109.5	H1B—N1—H1A	109.5
C2—C3—H3C	109.5
O2—C1—C2—N1	16.2 (5)	O2—C1—C2—C3	−106.5 (5)
O1—C1—C2—N1	−166.3 (3)	O1—C1—C2—C3	71.0 (5)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1B···O2^i	0.89	1.95	2.810 (3)	163
N1—H1A···O1^ii	0.89	1.88	2.763 (3)	173
N1—H1A···O2^ii	0.89	2.68	3.342 (3)	132
N1—H1C···O1^iii	0.89	1.90	2.750 (3)	159

Symmetry codes: (i) −x+1, −y+1, z−1/2; (ii) x, y, z−1; (iii) −x+3/2, y+1/2, z−1/2.

(dlala_20kbar) DL-2-Aminopropionic Acid

Crystal data

C3H7NO2	F(000) = 192
Mr = 89.10	Dx = 1.514 Mg m^−3
Orthorhombic, Pna21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2n	Cell parameters from 1447 reflections
a = 11.770 (3) Å	θ = 3.5–31.0°
b = 5.751 (4) Å	µ = 0.13 mm^−1
c = 5.7748 (8) Å	T = 293 K
V = 390.9 (3) Å^3	Plate, colorless
Z = 4	0.16 × 0.10 × 0.06 mm

Data collection

Oxford Diffraction Gemini Ultra R diffractometer	564 independent reflections
Graphite monochromator	432 reflections with I > 2σ(I)
Detector resolution: 10.3457 pixels mm^-1	Rint = 0.079
ω scans	θmax = 31.1°, θmin = 3.5°
Absorption correction: gaussian Absorb6.1 (R. J. Angel, 2004)	h = −15→15
Tmin = 0.410, Tmax = 0.478	k = −4→4
3228 measured reflections	l = −8→8

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.046	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.081	H-atom parameters constrained
S = 1.06	w = 1/[σ^2(Fo^2) + (0.0294P)^2] where P = (Fo^2 + 2Fc^2)/3
564 reflections	(Δ/σ)max < 0.001
57 parameters	Δρmax = 0.13 e Å^−3
1 restraint	Δρmin = −0.15 e Å^−3

Special details

Experimental. high pressure measurement at 2.0 GPa in the DAC

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O2	0.59149 (18)	0.4868 (7)	0.6048 (4)	0.0312 (15)
O1	0.68432 (15)	0.1767 (5)	0.7437 (3)	0.0328 (11)
C1	0.6438 (2)	0.2952 (10)	0.5814 (5)	0.0234 (17)
C2	0.6623 (2)	0.1998 (10)	0.3362 (4)	0.0213 (19)
H2	0.7423	0.1558	0.3204	0.026*
C3	0.5907 (2)	−0.0120 (12)	0.2937 (6)	0.036 (3)
H3B	0.6075	−0.0738	0.1431	0.043*
H3C	0.5118	0.0296	0.3013	0.043*
H3A	0.6070	−0.1271	0.4093	0.043*
N1	0.63680 (19)	0.3836 (7)	0.1627 (3)	0.0282 (12)
H1C	0.6826	0.5046	0.1856	0.034*
H1B	0.5649	0.4288	0.1778	0.034*
H1A	0.6477	0.3275	0.0208	0.034*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O2	0.0392 (13)	0.028 (5)	0.0263 (13)	0.0055 (11)	0.0007 (9)	−0.0037 (14)
O1	0.0378 (12)	0.042 (4)	0.0191 (8)	0.0066 (13)	−0.0013 (9)	0.0032 (15)
C1	0.0231 (17)	0.027 (6)	0.0198 (14)	−0.0039 (14)	0.0013 (11)	−0.003 (2)
C2	0.0266 (18)	0.022 (7)	0.0156 (13)	0.0002 (15)	0.0014 (9)	0.002 (2)
C3	0.039 (2)	0.044 (9)	0.023 (2)	−0.0040 (17)	−0.0016 (12)	−0.001 (2)
N1	0.0294 (14)	0.041 (5)	0.0145 (10)	−0.0025 (13)	0.0011 (9)	0.0001 (16)

Geometric parameters (Å, º)

O2—C1	1.270 (7)	C3—H3B	0.9600
O1—C1	1.253 (4)	C3—H3C	0.9600
C1—C2	1.534 (4)	C3—H3A	0.9600
C2—N1	1.487 (5)	N1—H1C	0.8900
C2—C3	1.501 (8)	N1—H1B	0.8900
C2—H2	0.9800	N1—H1A	0.8900
O1—C1—O2	125.2 (3)	H3B—C3—H3C	109.5
O1—C1—C2	116.2 (4)	C2—C3—H3A	109.5
O2—C1—C2	118.5 (3)	H3B—C3—H3A	109.5
N1—C2—C3	110.7 (3)	H3C—C3—H3A	109.5
N1—C2—C1	109.8 (4)	C2—N1—H1C	109.5
C3—C2—C1	111.2 (3)	C2—N1—H1B	109.5
N1—C2—H2	108.3	H1C—N1—H1B	109.5
C3—C2—H2	108.3	C2—N1—H1A	109.5
C1—C2—H2	108.3	H1C—N1—H1A	109.5
C2—C3—H3B	109.5	H1B—N1—H1A	109.5
C2—C3—H3C	109.5
O1—C1—C2—N1	−165.6 (4)	O1—C1—C2—C3	71.6 (4)
O2—C1—C2—N1	13.1 (5)	O2—C1—C2—C3	−109.8 (5)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1B···O2^i	0.89	1.95	2.808 (3)	162
N1—H1A···O1^ii	0.89	1.87	2.754 (3)	172
N1—H1A···O2^ii	0.89	2.66	3.319 (3)	132
N1—H1C···O1^iii	0.89	1.88	2.737 (4)	160

Symmetry codes: (i) −x+1, −y+1, z−1/2; (ii) x, y, z−1; (iii) −x+3/2, y+1/2, z−1/2.

(dlala_25kbar) DL-2-Aminopropionic Acid

Crystal data

C3H7NO2	F(000) = 192
Mr = 89.10	Dx = 1.550 Mg m^−3
Orthorhombic, Pna21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2n	Cell parameters from 1104 reflections
a = 11.677 (2) Å	θ = 3.6–31.2°
b = 5.705 (2) Å	µ = 0.13 mm^−1
c = 5.7311 (8) Å	T = 293 K
V = 381.76 (18) Å^3	Plate, colorless
Z = 4	0.16 × 0.10 × 0.06 mm

Data collection

Oxford Diffraction Gemini Ultra R diffractometer	428 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.063
Detector resolution: 10.3457 pixels mm^-1	θmax = 31.2°, θmin = 5.0°
ω scans	h = −15→14
2540 measured reflections	k = −5→5
571 independent reflections	l = −8→8

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.042	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.069	H-atom parameters constrained
S = 0.99	w = 1/[σ^2(Fo^2) + (0.0153P)^2] where P = (Fo^2 + 2Fc^2)/3
571 reflections	(Δ/σ)max < 0.001
57 parameters	Δρmax = 0.14 e Å^−3
1 restraint	Δρmin = −0.15 e Å^−3

Special details

Experimental. high pressure measurement at 2.5 GPa in the DAC

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O2	0.59113 (18)	0.4854 (6)	0.6056 (4)	0.0299 (9)
O1	0.68391 (17)	0.1718 (5)	0.7453 (3)	0.0316 (8)
C1	0.6445 (2)	0.2978 (8)	0.5819 (5)	0.0233 (12)
C2	0.6625 (2)	0.2001 (8)	0.3371 (5)	0.0205 (12)
H2	0.7433	0.1567	0.3206	0.025*
C3	0.5903 (3)	−0.0147 (9)	0.2902 (7)	0.0326 (14)
H3B	0.6072	−0.0740	0.1372	0.039*
H3C	0.5107	0.0263	0.2990	0.039*
H3A	0.6072	−0.1328	0.4044	0.039*
N1	0.63591 (19)	0.3813 (6)	0.1621 (3)	0.0273 (9)
H1C	0.6808	0.5053	0.1849	0.033*
H1B	0.5629	0.4240	0.1758	0.033*
H1A	0.6480	0.3240	0.0197	0.033*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O2	0.0351 (14)	0.032 (3)	0.0223 (13)	0.0097 (10)	0.0004 (11)	−0.0048 (13)
O1	0.0362 (13)	0.041 (3)	0.0176 (9)	0.0093 (10)	−0.0010 (10)	0.0027 (15)
C1	0.015 (2)	0.037 (5)	0.0176 (16)	−0.0054 (12)	0.0029 (12)	−0.003 (2)
C2	0.024 (2)	0.020 (5)	0.0169 (15)	0.0019 (12)	−0.0017 (11)	0.004 (2)
C3	0.039 (3)	0.030 (5)	0.028 (2)	−0.0020 (14)	−0.0002 (14)	0.0009 (19)
N1	0.0275 (16)	0.039 (4)	0.0159 (12)	−0.0029 (11)	0.0006 (10)	−0.0042 (16)

Geometric parameters (Å, º)

O2—C1	1.246 (5)	C3—H3B	0.9600
O1—C1	1.267 (4)	C3—H3C	0.9600
C1—C2	1.524 (4)	C3—H3A	0.9600
C2—N1	1.473 (4)	N1—H1C	0.8900
C2—C3	1.511 (6)	N1—H1B	0.8900
C2—H2	0.9800	N1—H1A	0.8900
O2—C1—O1	126.1 (3)	H3B—C3—H3C	109.5
O2—C1—C2	118.9 (3)	C2—C3—H3A	109.5
O1—C1—C2	115.0 (3)	H3B—C3—H3A	109.5
N1—C2—C3	109.3 (3)	H3C—C3—H3A	109.5
N1—C2—C1	110.0 (3)	C2—N1—H1C	109.5
C3—C2—C1	112.5 (3)	C2—N1—H1B	109.5
N1—C2—H2	108.3	H1C—N1—H1B	109.5
C3—C2—H2	108.3	C2—N1—H1A	109.5
C1—C2—H2	108.3	H1C—N1—H1A	109.5
C2—C3—H3B	109.5	H1B—N1—H1A	109.5
C2—C3—H3C	109.5
O2—C1—C2—N1	13.9 (5)	O2—C1—C2—C3	−108.2 (5)
O1—C1—C2—N1	−168.0 (3)	O1—C1—C2—C3	69.9 (4)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1B···O2^i	0.89	1.91	2.777 (3)	163
N1—H1A···O1^ii	0.89	1.84	2.729 (3)	172
N1—H1A···O2^ii	0.89	2.63	3.286 (3)	131
N1—H1C···O1^iii	0.89	1.88	2.721 (3)	158

Symmetry codes: (i) −x+1, −y+1, z−1/2; (ii) x, y, z−1; (iii) −x+3/2, y+1/2, z−1/2.

(dlala_30kbar) DL-2-Aminopropionic Acid

Crystal data

C3H7NO2	F(000) = 192
Mr = 89.10	Dx = 1.562 Mg m^−3
Orthorhombic, Pna21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2n	Cell parameters from 1377 reflections
a = 11.6535 (18) Å	θ = 3.5–31.0°
b = 5.681 (3) Å	µ = 0.13 mm^−1
c = 5.7217 (6) Å	T = 293 K
V = 378.8 (2) Å^3	Plate, colorless
Z = 4	0.16 × 0.10 × 0.06 mm

Data collection

Oxford Diffraction Gemini Ultra R diffractometer	399 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.070
Detector resolution: 10.3457 pixels mm^-1	θmax = 31.0°, θmin = 3.5°
ω scans	h = −16→16
3073 measured reflections	k = −4→4
510 independent reflections	l = −8→8

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.037	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.059	H-atom parameters constrained
S = 1.00	w = 1/[σ^2(Fo^2) + (0.0188P)^2] where P = (Fo^2 + 2Fc^2)/3
510 reflections	(Δ/σ)max < 0.001
57 parameters	Δρmax = 0.13 e Å^−3
1 restraint	Δρmin = −0.14 e Å^−3

Special details

Experimental. high pressure measurement at 3.0 GPa in the DAC

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O2	0.59156 (15)	0.4875 (7)	0.6056 (4)	0.0297 (15)
O1	0.68403 (12)	0.1671 (6)	0.7456 (3)	0.0339 (13)
C1	0.6443 (2)	0.2950 (10)	0.5841 (5)	0.031 (2)
C2	0.66270 (18)	0.1982 (10)	0.3361 (4)	0.023 (2)
H2	0.7436	0.1544	0.3188	0.027*
C3	0.58968 (19)	−0.0173 (12)	0.2908 (5)	0.032 (3)
H3B	0.6038	−0.0738	0.1353	0.038*
H3C	0.5101	0.0232	0.3067	0.038*
H3A	0.6089	−0.1379	0.4016	0.038*
N1	0.63525 (16)	0.3800 (8)	0.1610 (2)	0.0290 (15)
H1C	0.6800	0.5049	0.1836	0.035*
H1B	0.5620	0.4221	0.1755	0.035*
H1A	0.6471	0.3227	0.0183	0.035*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O2	0.0369 (11)	0.027 (5)	0.0251 (11)	0.0031 (13)	−0.0025 (9)	−0.0020 (13)
O1	0.0375 (10)	0.048 (4)	0.0160 (7)	0.0097 (12)	−0.0010 (8)	0.0086 (15)
C1	0.0174 (15)	0.059 (8)	0.0176 (13)	−0.0100 (16)	0.0011 (10)	−0.006 (3)
C2	0.0225 (14)	0.030 (7)	0.0146 (12)	−0.0022 (16)	−0.0007 (8)	0.008 (2)
C3	0.0397 (15)	0.035 (9)	0.0210 (16)	−0.0023 (18)	−0.0026 (10)	−0.0007 (19)
N1	0.0307 (12)	0.043 (5)	0.0133 (9)	−0.0038 (13)	0.0014 (8)	−0.0042 (18)

Geometric parameters (Å, º)

O2—C1	1.260 (6)	C3—H3B	0.9600
O1—C1	1.264 (5)	C3—H3C	0.9600
C1—C2	1.537 (4)	C3—H3A	0.9600
C2—N1	1.474 (6)	N1—H1C	0.8900
C2—C3	1.513 (8)	N1—H1B	0.8900
C2—H2	0.9800	N1—H1A	0.8900
O2—C1—O1	127.3 (3)	H3B—C3—H3C	109.5
O2—C1—C2	118.0 (3)	C2—C3—H3A	109.5
O1—C1—C2	114.7 (4)	H3B—C3—H3A	109.5
N1—C2—C3	109.2 (3)	H3C—C3—H3A	109.5
N1—C2—C1	110.3 (4)	C2—N1—H1C	109.5
C3—C2—C1	111.7 (3)	C2—N1—H1B	109.5
N1—C2—H2	108.6	H1C—N1—H1B	109.5
C3—C2—H2	108.6	C2—N1—H1A	109.5
C1—C2—H2	108.6	H1C—N1—H1A	109.5
C2—C3—H3B	109.5	H1B—N1—H1A	109.5
C2—C3—H3C	109.5
O2—C1—C2—N1	12.2 (4)	O2—C1—C2—C3	−109.3 (5)
O1—C1—C2—N1	−168.4 (4)	O1—C1—C2—C3	70.1 (4)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1B···O2^i	0.89	1.90	2.767 (3)	163
N1—H1A···O1^ii	0.89	1.84	2.727 (3)	171
N1—H1A···O2^ii	0.89	2.62	3.276 (3)	131
N1—H1C···O1^iii	0.89	1.87	2.708 (4)	157

Symmetry codes: (i) −x+1, −y+1, z−1/2; (ii) x, y, z−1; (iii) −x+3/2, y+1/2, z−1/2.

(dlala_36kbar) DL-2-Aminopropionic Acid

Crystal data

C3H7NO2	F(000) = 192
Mr = 89.10	Dx = 1.588 Mg m^−3
Orthorhombic, Pna21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2n	Cell parameters from 711 reflections
a = 11.617 (3) Å	θ = 3.6–30.6°
b = 5.611 (4) Å	µ = 0.13 mm^−1
c = 5.7156 (15) Å	T = 293 K
V = 372.6 (3) Å^3	Plate, colorless
Z = 4	0.16 × 0.10 × 0.06 mm

Data collection

Oxford Diffraction Gemini Ultra R diffractometer	359 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.062
Detector resolution: 10.3457 pixels mm^-1	θmax = 30.7°, θmin = 5.0°
ω scans	h = −15→15
1714 measured reflections	k = −4→4
477 independent reflections	l = −7→7

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.040	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.073	H-atom parameters constrained
S = 1.00	w = 1/[σ^2(Fo^2) + (0.0276P)^2] where P = (Fo^2 + 2Fc^2)/3
477 reflections	(Δ/σ)max < 0.001
57 parameters	Δρmax = 0.15 e Å^−3
1 restraint	Δρmin = −0.15 e Å^−3

Special details

Experimental. high pressure measurement at 3.6 GPa in the DAC

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O2	0.59274 (19)	0.4843 (8)	0.6076 (5)	0.0306 (14)
O1	0.68409 (17)	0.1645 (6)	0.7455 (4)	0.0282 (10)
C1	0.6445 (2)	0.2921 (10)	0.5818 (6)	0.0215 (17)
C2	0.6623 (2)	0.1965 (10)	0.3351 (5)	0.0177 (16)
H2	0.7436	0.1531	0.3171	0.021*
C3	0.5897 (3)	−0.0235 (12)	0.2904 (7)	0.029 (2)
H3B	0.6073	−0.0864	0.1384	0.035*
H3A	0.5097	0.0183	0.2974	0.035*
H3C	0.6063	−0.1415	0.4073	0.035*
N1	0.6344 (2)	0.3796 (8)	0.1609 (4)	0.0243 (13)
H1C	0.6808	0.5042	0.1799	0.029*
H1A	0.5616	0.4256	0.1793	0.029*
H1B	0.6437	0.3200	0.0179	0.029*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O2	0.0325 (12)	0.036 (5)	0.0233 (17)	0.0062 (11)	−0.0001 (11)	−0.0023 (17)
O1	0.0358 (12)	0.033 (3)	0.0160 (12)	0.0068 (11)	−0.0005 (9)	0.0037 (19)
C1	0.0138 (16)	0.031 (6)	0.020 (2)	−0.0038 (13)	0.0030 (14)	0.002 (3)
C2	0.0209 (17)	0.019 (6)	0.013 (2)	0.0020 (15)	0.0003 (11)	0.001 (2)
C3	0.0365 (19)	0.027 (7)	0.025 (3)	−0.0029 (16)	−0.0014 (13)	0.002 (2)
N1	0.0279 (15)	0.030 (5)	0.0147 (17)	−0.0028 (12)	0.0007 (10)	−0.003 (2)

Geometric parameters (Å, º)

O2—C1	1.244 (7)	C3—H3B	0.9600
O1—C1	1.265 (5)	C3—H3A	0.9600
C1—C2	1.523 (5)	C3—H3C	0.9600
C2—N1	1.467 (5)	N1—H1C	0.8900
C2—C3	1.516 (8)	N1—H1A	0.8900
C2—H2	0.9800	N1—H1B	0.8900
O2—C1—O1	125.4 (4)	H3B—C3—H3A	109.5
O2—C1—C2	118.8 (4)	C2—C3—H3C	109.5
O1—C1—C2	115.9 (4)	H3B—C3—H3C	109.5
N1—C2—C3	109.4 (3)	H3A—C3—H3C	109.5
N1—C2—C1	110.6 (4)	C2—N1—H1C	109.5
C3—C2—C1	111.5 (3)	C2—N1—H1A	109.5
N1—C2—H2	108.4	H1C—N1—H1A	109.5
C3—C2—H2	108.4	C2—N1—H1B	109.5
C1—C2—H2	108.4	H1C—N1—H1B	109.5
C2—C3—H3B	109.5	H1A—N1—H1B	109.5
C2—C3—H3A	109.5
O2—C1—C2—N1	11.9 (5)	O2—C1—C2—C3	−110.1 (6)
O1—C1—C2—N1	−168.5 (4)	O1—C1—C2—C3	69.4 (4)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O2^i	0.89	1.91	2.764 (3)	161
N1—H1B···O1^ii	0.89	1.85	2.725 (4)	170
N1—H1B···O2^ii	0.89	2.59	3.253 (4)	132
N1—H1C···O1^iii	0.89	1.85	2.690 (4)	157

Symmetry codes: (i) −x+1, −y+1, z−1/2; (ii) x, y, z−1; (iii) −x+3/2, y+1/2, z−1/2.

(dlala_41kbar) DL-2-Aminopropionic Acid

Crystal data

C3H7NO2	F(000) = 192
Mr = 89.10	Dx = 1.598 Mg m^−3
Orthorhombic, Pna21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2n	Cell parameters from 1389 reflections
a = 11.5877 (17) Å	θ = 3.5–31.1°
b = 5.617 (3) Å	µ = 0.13 mm^−1
c = 5.6894 (5) Å	T = 293 K
V = 370.3 (2) Å^3	Plate, colorless
Z = 4	0.16 × 0.10 × 0.06 mm

Data collection

Oxford Diffraction Gemini Ultra R diffractometer	528 independent reflections
Graphite monochromator	420 reflections with I > 2σ(I)
Detector resolution: 10.3457 pixels mm^-1	Rint = 0.064
ω scans	θmax = 31.1°, θmin = 3.5°
Absorption correction: gaussian Absorb6.1 (R. J. Angel, 2004)	h = −16→15
Tmin = 0.407, Tmax = 0.478	k = −4→4
3067 measured reflections	l = −8→8

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.040	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.063	H-atom parameters constrained
S = 1.03	w = 1/[σ^2(Fo^2) + (0.0226P)^2] where P = (Fo^2 + 2Fc^2)/3
528 reflections	(Δ/σ)max = 0.040
57 parameters	Δρmax = 0.14 e Å^−3
1 restraint	Δρmin = −0.12 e Å^−3

Special details

Experimental. high pressure measurement at 4.1 GPa in the DAC

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O2	0.59313 (16)	0.4854 (7)	0.6080 (3)	0.0269 (12)
O1	0.68393 (12)	0.1626 (6)	0.7461 (3)	0.0291 (11)
C1	0.6451 (2)	0.2911 (10)	0.5840 (4)	0.0253 (18)
C2	0.66259 (17)	0.1938 (9)	0.3346 (4)	0.0193 (17)
H2	0.7440	0.1507	0.3155	0.023*
C3	0.5899 (2)	−0.0244 (11)	0.2899 (5)	0.029 (2)
H3B	0.6044	−0.0821	0.1338	0.035*
H3A	0.5098	0.0158	0.3054	0.035*
H3C	0.6094	−0.1457	0.4019	0.035*
N1	0.63363 (16)	0.3793 (7)	0.1597 (3)	0.0230 (13)
H1C	0.6793	0.5050	0.1807	0.028*
H1A	0.5603	0.4230	0.1776	0.028*
H1B	0.6439	0.3217	0.0155	0.028*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O2	0.0326 (10)	0.025 (4)	0.0228 (11)	0.0041 (10)	−0.0002 (8)	−0.0031 (13)
O1	0.0312 (10)	0.039 (4)	0.0166 (7)	0.0083 (10)	0.0001 (7)	0.0057 (14)
C1	0.0138 (13)	0.045 (6)	0.0169 (14)	−0.0065 (13)	0.0009 (10)	−0.005 (2)
C2	0.0180 (14)	0.025 (6)	0.0149 (12)	0.0034 (14)	−0.0008 (8)	0.0043 (19)
C3	0.0326 (15)	0.036 (7)	0.0196 (15)	−0.0011 (15)	−0.0021 (9)	0.0029 (18)
N1	0.0278 (13)	0.028 (4)	0.0138 (10)	−0.0037 (11)	0.0009 (7)	−0.0083 (17)

Geometric parameters (Å, º)

O2—C1	1.254 (6)	C3—H3B	0.9600
O1—C1	1.254 (4)	C3—H3A	0.9600
C1—C2	1.534 (3)	C3—H3C	0.9600
C2—N1	1.480 (5)	N1—H1C	0.8900
C2—C3	1.508 (7)	N1—H1A	0.8900
C2—H2	0.9800	N1—H1B	0.8900
O2—C1—O1	126.4 (3)	H3B—C3—H3A	109.5
O2—C1—C2	118.3 (3)	C2—C3—H3C	109.5
O1—C1—C2	115.3 (4)	H3B—C3—H3C	109.5
N1—C2—C3	109.4 (2)	H3A—C3—H3C	109.5
N1—C2—C1	110.0 (4)	C2—N1—H1C	109.5
C3—C2—C1	111.8 (3)	C2—N1—H1A	109.5
N1—C2—H2	108.5	H1C—N1—H1A	109.5
C3—C2—H2	108.5	C2—N1—H1B	109.5
C1—C2—H2	108.5	H1C—N1—H1B	109.5
C2—C3—H3B	109.5	H1A—N1—H1B	109.5
C2—C3—H3A	109.5
O2—C1—C2—N1	11.6 (4)	O2—C1—C2—C3	−110.1 (5)
O1—C1—C2—N1	−169.4 (3)	O1—C1—C2—C3	68.9 (4)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O2^i	0.89	1.89	2.751 (3)	161
N1—H1B···O1^ii	0.89	1.83	2.713 (3)	169
N1—H1B···O2^ii	0.89	2.56	3.229 (3)	132
N1—H1C···O1^iii	0.89	1.85	2.691 (3)	156

Symmetry codes: (i) −x+1, −y+1, z−1/2; (ii) x, y, z−1; (iii) −x+3/2, y+1/2, z−1/2.

(dlala_45kbar) DL-2-Aminopropionic Acid

Crystal data

C3H7NO2	F(000) = 192
Mr = 89.10	Dx = 1.620 Mg m^−3
Orthorhombic, Pna21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2n	Cell parameters from 988 reflections
a = 11.572 (4) Å	θ = 3.6–31.0°
b = 5.567 (5) Å	µ = 0.14 mm^−1
c = 5.6710 (11) Å	T = 293 K
V = 365.4 (3) Å^3	Plate, colorless
Z = 4	0.16 × 0.10 × 0.06 mm

Data collection

Oxford Diffraction Gemini Ultra R diffractometer	529 independent reflections
Graphite monochromator	385 reflections with I > 2σ(I)
Detector resolution: 10.3457 pixels mm^-1	Rint = 0.078
ω scans	θmax = 31.0°, θmin = 5.0°
Absorption correction: gaussian Absorb6.1 (R. J. Angel, 2004)	h = −15→15
Tmin = 0.408, Tmax = 0.478	k = −4→4
2420 measured reflections	l = −8→8

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.041	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.078	H-atom parameters constrained
S = 0.95	w = 1/[σ^2(Fo^2) + (0.0259P)^2] where P = (Fo^2 + 2Fc^2)/3
529 reflections	(Δ/σ)max < 0.001
57 parameters	Δρmax = 0.15 e Å^−3
1 restraint	Δρmin = −0.14 e Å^−3

Special details

Experimental. high pressure measurement at 4.1 GPa in the DAC

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O2	0.5938 (2)	0.4859 (7)	0.6098 (4)	0.0296 (11)
O1	0.68400 (17)	0.1605 (6)	0.7463 (4)	0.0319 (10)
C1	0.6446 (3)	0.2888 (11)	0.5824 (6)	0.0297 (19)
C2	0.6620 (2)	0.1920 (9)	0.3323 (5)	0.0222 (16)
H2	0.7435	0.1487	0.3128	0.027*
C3	0.5897 (3)	−0.0282 (11)	0.2906 (7)	0.0320 (19)
H3B	0.6075	−0.0942	0.1385	0.038*
H3A	0.5093	0.0141	0.2965	0.038*
H3C	0.6060	−0.1454	0.4103	0.038*
N1	0.6333 (2)	0.3785 (7)	0.1596 (3)	0.0257 (12)
H1C	0.6781	0.5062	0.1833	0.031*
H1A	0.5595	0.4204	0.1760	0.031*
H1B	0.6449	0.3222	0.0146	0.031*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O2	0.0343 (13)	0.030 (4)	0.0247 (14)	0.0039 (11)	0.0004 (10)	−0.0029 (16)
O1	0.0333 (13)	0.043 (4)	0.0196 (10)	0.0066 (10)	−0.0012 (9)	0.0020 (17)
C1	0.0185 (19)	0.050 (7)	0.0210 (17)	−0.0046 (15)	0.0010 (14)	−0.002 (2)
C2	0.0221 (18)	0.032 (6)	0.0128 (16)	0.0012 (15)	0.0009 (10)	0.004 (2)
C3	0.034 (2)	0.038 (7)	0.024 (2)	−0.0028 (16)	−0.0030 (12)	0.003 (2)
N1	0.0328 (18)	0.031 (5)	0.0134 (12)	−0.0036 (12)	0.0009 (10)	−0.0050 (19)

Geometric parameters (Å, º)

O2—C1	1.255 (7)	C3—H3B	0.9600
O1—C1	1.258 (5)	C3—H3A	0.9600
C1—C2	1.531 (4)	C3—H3C	0.9600
C2—N1	1.465 (5)	N1—H1C	0.8900
C2—C3	1.503 (7)	N1—H1A	0.8900
C2—H2	0.9800	N1—H1B	0.8900
O2—C1—O1	125.1 (4)	H3B—C3—H3A	109.5
O2—C1—C2	119.0 (4)	C2—C3—H3C	109.5
O1—C1—C2	115.9 (4)	H3B—C3—H3C	109.5
N1—C2—C3	110.3 (3)	H3A—C3—H3C	109.5
N1—C2—C1	109.9 (4)	C2—N1—H1C	109.5
C3—C2—C1	111.1 (3)	C2—N1—H1A	109.5
N1—C2—H2	108.5	H1C—N1—H1A	109.5
C3—C2—H2	108.5	C2—N1—H1B	109.5
C1—C2—H2	108.5	H1C—N1—H1B	109.5
C2—C3—H3B	109.5	H1A—N1—H1B	109.5
C2—C3—H3A	109.5
O2—C1—C2—N1	10.9 (5)	O2—C1—C2—C3	−111.4 (6)
O1—C1—C2—N1	−168.9 (4)	O1—C1—C2—C3	68.8 (5)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O2^i	0.89	1.89	2.749 (3)	163
N1—H1B···O1^ii	0.89	1.83	2.704 (3)	169
N1—H1B···O2^ii	0.89	2.54	3.208 (3)	132
N1—H1C···O1^iii	0.89	1.85	2.679 (4)	155

Symmetry codes: (i) −x+1, −y+1, z−1/2; (ii) x, y, z−1; (iii) −x+3/2, y+1/2, z−1/2.

(dlala_50kbar) DL-2-Aminopropionic Acid

Crystal data

C3H7NO2	F(000) = 192
Mr = 89.10	Dx = 1.636 Mg m^−3
Orthorhombic, Pna21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2n	Cell parameters from 1408 reflections
a = 11.537 (3) Å	θ = 3.6–31.0°
b = 5.554 (3) Å	µ = 0.14 mm^−1
c = 5.6456 (8) Å	T = 293 K
V = 361.7 (2) Å^3	Plate, colorless
Z = 4	0.16 × 0.10 × 0.06 mm

Data collection

Oxford Diffraction Gemini Ultra R diffractometer	499 independent reflections
Graphite monochromator	396 reflections with I > 2σ(I)
Detector resolution: 10.3457 pixels mm^-1	Rint = 0.075
ω scans	θmax = 31.1°, θmin = 5.1°
Absorption correction: gaussian Absorb6.1 (R. J. Angel, 2004)	h = −14→14
Tmin = 0.408, Tmax = 0.478	k = −4→4
3018 measured reflections	l = −8→8

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.042	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.079	H-atom parameters constrained
S = 1.05	w = 1/[σ^2(Fo^2) + (0.0327P)^2] where P = (Fo^2 + 2Fc^2)/3
499 reflections	(Δ/σ)max < 0.001
57 parameters	Δρmax = 0.16 e Å^−3
1 restraint	Δρmin = −0.15 e Å^−3

Special details

Experimental. high pressure measurement at 5.0 GPa in the DAC

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O2	0.5940 (2)	0.4834 (7)	0.6102 (3)	0.0278 (9)
O1	0.68384 (16)	0.1575 (5)	0.7474 (3)	0.0261 (8)
C1	0.6452 (2)	0.2890 (9)	0.5832 (5)	0.0218 (14)
C2	0.6624 (2)	0.1900 (9)	0.3325 (4)	0.0211 (14)
H2	0.7442	0.1468	0.3121	0.025*
C3	0.5895 (3)	−0.0286 (11)	0.2882 (6)	0.0318 (17)
H3B	0.6080	−0.0943	0.1355	0.038*
H3A	0.5091	0.0152	0.2924	0.038*
H3C	0.6048	−0.1468	0.4082	0.038*
N1	0.6323 (2)	0.3778 (7)	0.1586 (3)	0.0251 (11)
H1C	0.6772	0.5061	0.1814	0.030*
H1A	0.5584	0.4194	0.1766	0.030*
H1B	0.6433	0.3213	0.0128	0.030*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O2	0.0315 (13)	0.031 (3)	0.0209 (11)	0.0059 (11)	0.0003 (9)	−0.0014 (13)
O1	0.0335 (14)	0.027 (3)	0.0177 (9)	0.0078 (9)	−0.0004 (8)	0.0030 (14)
C1	0.0113 (19)	0.033 (5)	0.0214 (16)	−0.0017 (12)	0.0021 (12)	0.0029 (19)
C2	0.0203 (19)	0.029 (5)	0.0139 (14)	−0.0001 (14)	−0.0011 (9)	0.0009 (18)
C3	0.035 (2)	0.038 (6)	0.0222 (17)	−0.0029 (15)	−0.0030 (12)	0.002 (2)
N1	0.0246 (16)	0.036 (4)	0.0144 (12)	−0.0041 (11)	0.0005 (9)	−0.0016 (16)

Geometric parameters (Å, º)

O2—C1	1.240 (6)	C3—H3B	0.9600
O1—C1	1.262 (4)	C3—H3A	0.9600
C1—C2	1.531 (4)	C3—H3C	0.9600
C2—N1	1.474 (5)	N1—H1C	0.8900
C2—C3	1.498 (7)	N1—H1A	0.8900
C2—H2	0.9800	N1—H1B	0.8900
O2—C1—O1	125.6 (3)	H3B—C3—H3A	109.5
O2—C1—C2	119.2 (3)	C2—C3—H3C	109.5
O1—C1—C2	115.2 (3)	H3B—C3—H3C	109.5
N1—C2—C3	109.3 (3)	H3A—C3—H3C	109.5
N1—C2—C1	109.3 (3)	C2—N1—H1C	109.5
C3—C2—C1	111.9 (3)	C2—N1—H1A	109.5
N1—C2—H2	108.8	H1C—N1—H1A	109.5
C3—C2—H2	108.8	C2—N1—H1B	109.5
C1—C2—H2	108.8	H1C—N1—H1B	109.5
C2—C3—H3B	109.5	H1A—N1—H1B	109.5
C2—C3—H3A	109.5
O2—C1—C2—N1	11.1 (5)	O2—C1—C2—C3	−110.0 (5)
O1—C1—C2—N1	−170.2 (3)	O1—C1—C2—C3	68.6 (4)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O2^i	0.89	1.88	2.737 (3)	162
N1—H1B···O1^ii	0.89	1.81	2.691 (3)	168
N1—H1B···O2^ii	0.89	2.51	3.182 (3)	133
N1—H1C···O1^iii	0.89	1.85	2.676 (4)	154

Symmetry codes: (i) −x+1, −y+1, z−1/2; (ii) x, y, z−1; (iii) −x+3/2, y+1/2, z−1/2.

(dlala_55kbar) DL-2-Aminopropionic Acid

Crystal data

C3H7NO2	F(000) = 192
Mr = 89.10	Dx = 1.657 Mg m^−3
Orthorhombic, Pna21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2n	Cell parameters from 1339 reflections
a = 11.4915 (17) Å	θ = 3.6–30.6°
b = 5.5249 (18) Å	µ = 0.14 mm^−1
c = 5.6262 (5) Å	T = 293 K
V = 357.21 (13) Å^3	Plate, colorless
Z = 4	0.16 × 0.10 × 0.06 mm

Data collection

Oxford Diffraction Gemini Ultra R diffractometer	512 independent reflections
Graphite monochromator	425 reflections with I > 2σ(I)
Detector resolution: 10.3457 pixels mm^-1	Rint = 0.068
ω scans	θmax = 30.7°, θmin = 4.1°
Absorption correction: gaussian Absorb6.1 (R. J. Angel, 2004)	h = −14→14
Tmin = 0.409, Tmax = 0.478	k = −5→5
2999 measured reflections	l = −8→8

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.041	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.071	H-atom parameters constrained
S = 1.09	w = 1/[σ^2(Fo^2) + (0.0256P)^2] where P = (Fo^2 + 2Fc^2)/3
512 reflections	(Δ/σ)max < 0.001
57 parameters	Δρmax = 0.15 e Å^−3
1 restraint	Δρmin = −0.13 e Å^−3

Special details

Experimental. high pressure measurement at 5.5 GPa in the DAC

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O2	0.59485 (19)	0.4835 (6)	0.6110 (3)	0.0282 (9)
O1	0.68382 (16)	0.1534 (5)	0.7477 (3)	0.0271 (7)
C1	0.6451 (2)	0.2889 (8)	0.5829 (4)	0.0215 (12)
C2	0.6621 (2)	0.1901 (8)	0.3317 (4)	0.0187 (11)
H2	0.7442	0.1476	0.3108	0.022*
C3	0.5899 (3)	−0.0305 (9)	0.2881 (5)	0.0259 (12)
H3B	0.6094	−0.0980	0.1360	0.031*
H3A	0.5090	0.0127	0.2900	0.031*
H3C	0.6048	−0.1478	0.4102	0.031*
N1	0.63158 (19)	0.3770 (6)	0.1585 (3)	0.0260 (10)
H1C	0.6764	0.5063	0.1810	0.031*
H1A	0.5573	0.4183	0.1769	0.031*
H1B	0.6425	0.3202	0.0122	0.031*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O2	0.0298 (13)	0.032 (3)	0.0225 (11)	0.0070 (10)	0.0012 (8)	−0.0035 (12)
O1	0.0318 (13)	0.034 (3)	0.0157 (8)	0.0075 (9)	−0.0011 (8)	−0.0003 (12)
C1	0.0101 (17)	0.037 (5)	0.0180 (14)	−0.0040 (11)	0.0018 (11)	0.0005 (17)
C2	0.0203 (18)	0.023 (4)	0.0132 (13)	0.0004 (12)	−0.0017 (9)	0.0013 (16)
C3	0.035 (2)	0.022 (4)	0.0206 (16)	−0.0025 (13)	0.0001 (11)	0.0002 (17)
N1	0.0255 (16)	0.037 (4)	0.0159 (11)	−0.0037 (10)	0.0006 (8)	−0.0017 (16)

Geometric parameters (Å, º)

O2—C1	1.231 (5)	C3—H3B	0.9600
O1—C1	1.272 (4)	C3—H3A	0.9600
C1—C2	1.528 (3)	C3—H3C	0.9600
C2—N1	1.463 (5)	N1—H1C	0.8900
C2—C3	1.495 (6)	N1—H1A	0.8900
C2—H2	0.9800	N1—H1B	0.8900
O2—C1—O1	125.8 (3)	H3B—C3—H3A	109.5
O2—C1—C2	119.4 (3)	C2—C3—H3C	109.5
O1—C1—C2	114.8 (3)	H3B—C3—H3C	109.5
N1—C2—C3	109.5 (2)	H3A—C3—H3C	109.5
N1—C2—C1	109.5 (3)	C2—N1—H1C	109.5
C3—C2—C1	111.9 (3)	C2—N1—H1A	109.5
N1—C2—H2	108.7	H1C—N1—H1A	109.5
C3—C2—H2	108.7	C2—N1—H1B	109.5
C1—C2—H2	108.7	H1C—N1—H1B	109.5
C2—C3—H3B	109.5	H1A—N1—H1B	109.5
C2—C3—H3A	109.5
O2—C1—C2—N1	10.5 (4)	O2—C1—C2—C3	−111.0 (5)
O1—C1—C2—N1	−170.9 (3)	O1—C1—C2—C3	67.5 (4)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O2^i	0.89	1.87	2.727 (3)	162
N1—H1B···O1^ii	0.89	1.81	2.689 (3)	167
N1—H1B···O2^ii	0.89	2.49	3.164 (3)	133
N1—H1C···O1^iii	0.89	1.84	2.662 (3)	153

Symmetry codes: (i) −x+1, −y+1, z−1/2; (ii) x, y, z−1; (iii) −x+3/2, y+1/2, z−1/2.

(dlala_60kbar) DL-2-Aminopropionic Acid

Crystal data

C3H7NO2	F(000) = 192
Mr = 89.10	Dx = 1.671 Mg m^−3
Orthorhombic, Pna21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2n	Cell parameters from 1267 reflections
a = 11.452 (3) Å	θ = 3.6–30.9°
b = 5.516 (3) Å	µ = 0.14 mm^−1
c = 5.6060 (7) Å	T = 293 K
V = 354.10 (19) Å^3	Plate, colorless
Z = 4	0.16 × 0.10 × 0.06 mm

Data collection

Oxford Diffraction Gemini Ultra R diffractometer	511 independent reflections
Graphite monochromator	387 reflections with I > 2σ(I)
Detector resolution: 10.3457 pixels mm^-1	Rint = 0.072
ω scans	θmax = 31.0°, θmin = 4.1°
Absorption correction: gaussian Absorb6.1 (R. J. Angel, 2004)	h = −14→14
Tmin = 0.410, Tmax = 0.478	k = −5→5
2988 measured reflections	l = −8→8

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.040	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.071	H-atom parameters constrained
S = 1.00	w = 1/[σ^2(Fo^2) + (0.0244P)^2] where P = (Fo^2 + 2Fc^2)/3
511 reflections	(Δ/σ)max < 0.001
57 parameters	Δρmax = 0.14 e Å^−3
1 restraint	Δρmin = −0.13 e Å^−3

Special details

Experimental. high pressure measurement at 6.0 GPa in the DAC

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O2	0.5952 (2)	0.4837 (6)	0.6131 (4)	0.0261 (9)
O1	0.68412 (17)	0.1506 (5)	0.7476 (3)	0.0279 (8)
C1	0.6452 (2)	0.2841 (8)	0.5824 (5)	0.0209 (12)
C2	0.6621 (2)	0.1898 (8)	0.3312 (4)	0.0195 (12)
H2	0.7446	0.1481	0.3097	0.023*
C3	0.5895 (3)	−0.0342 (10)	0.2874 (6)	0.0284 (12)
H3B	0.6077	−0.0994	0.1331	0.034*
H3A	0.5081	0.0074	0.2935	0.034*
H3C	0.6063	−0.1530	0.4077	0.034*
N1	0.63087 (19)	0.3762 (6)	0.1576 (3)	0.0248 (10)
H1C	0.6752	0.5066	0.1804	0.030*
H1A	0.5561	0.4160	0.1756	0.030*
H1B	0.6423	0.3195	0.0108	0.030*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O2	0.0318 (14)	0.026 (3)	0.0206 (12)	0.0043 (10)	−0.0007 (9)	−0.0019 (12)
O1	0.0312 (14)	0.033 (3)	0.0195 (9)	0.0065 (9)	0.0002 (9)	0.0035 (13)
C1	0.016 (2)	0.024 (5)	0.0225 (17)	−0.0022 (13)	0.0031 (12)	0.0001 (19)
C2	0.018 (2)	0.027 (5)	0.0135 (15)	0.0007 (13)	−0.0006 (10)	0.0027 (17)
C3	0.035 (2)	0.023 (5)	0.0267 (18)	−0.0022 (14)	−0.0035 (13)	−0.0021 (18)
N1	0.0268 (17)	0.035 (4)	0.0123 (11)	−0.0026 (10)	−0.0015 (9)	−0.0001 (16)

Geometric parameters (Å, º)

O2—C1	1.253 (5)	C3—H3B	0.9600
O1—C1	1.264 (4)	C3—H3A	0.9600
C1—C2	1.513 (4)	C3—H3C	0.9600
C2—N1	1.460 (5)	N1—H1C	0.8900
C2—C3	1.510 (6)	N1—H1A	0.8900
C2—H2	0.9800	N1—H1B	0.8900
O2—C1—O1	124.9 (3)	H3B—C3—H3A	109.5
O2—C1—C2	119.2 (3)	C2—C3—H3C	109.5
O1—C1—C2	115.9 (3)	H3B—C3—H3C	109.5
N1—C2—C3	109.4 (3)	H3A—C3—H3C	109.5
N1—C2—C1	110.3 (3)	C2—N1—H1C	109.5
C3—C2—C1	111.2 (3)	C2—N1—H1A	109.5
N1—C2—H2	108.6	H1C—N1—H1A	109.5
C3—C2—H2	108.6	C2—N1—H1B	109.5
C1—C2—H2	108.6	H1C—N1—H1B	109.5
C2—C3—H3B	109.5	H1A—N1—H1B	109.5
C2—C3—H3A	109.5
O2—C1—C2—N1	9.0 (5)	O2—C1—C2—C3	−112.6 (5)
O1—C1—C2—N1	−170.9 (3)	O1—C1—C2—C3	67.5 (5)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O2^i	0.89	1.85	2.713 (3)	162
N1—H1B···O1^ii	0.89	1.81	2.684 (3)	167
N1—H1B···O2^ii	0.89	2.47	3.136 (3)	132
N1—H1C···O1^iii	0.89	1.84	2.652 (4)	152

Symmetry codes: (i) −x+1, −y+1, z−1/2; (ii) x, y, z−1; (iii) −x+3/2, y+1/2, z−1/2.