Protonated crystals of glycine silver nitrate (C4H10Ag2N4O10) undergo a displacive kind of structural phase transition to a ferroelectric phase at 218 K. Glycine silver nitrate (GSN) is a light-sensitive crystal. Single-crystal X-ray diffraction investigations are difficult to perform on these crystals due to the problem of crystal deterioration on prolonged exposure to X-rays. To circumvent this problem, single-crystal neutron diffraction investigations were performed. We report here the crystal structure of GSN in a ferroelectric phase. The final R value for the refined structure at 150 K is 0.059. A comparison of the low-temperature structure with the room-temperature structure throws some light on the mechanism of the structural phase change in this crystal. We have attempted to explain the structural transition in GSN within the framework of the vibronic theory of ferroelectricity, suggesting that the second-order Jahn-Teller (pseudo-Jahn-Teller) behavior of the Ag+ ion in GSN leads to structural distortion at low temperature (218 K).
Supporting information
Crystal data, data collection and structure refinement details are summarized in Table 1.
S2. Results and discussion
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For both compounds, data collection: HKLgen; cell refinement: Rafin; data reduction: TriCs_ccl. Program(s) used to solve structure: SHELXL97 (Sheldrick, 1997) for gsnltc; SHELXS97 (Sheldrick, 1990) for gsnrt. For both compounds, program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP; software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).
(gsnltc) Glycine Silver Nitrate
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Crystal data top
C4H10Ag2N2O4·2(NO3) | F(000) = 24 |
Mr = 489.90 | Dx = 2.858 Mg m−3 |
Monoclinic, P21 | Neutron radiation, λ = 1.17610 Å |
a = 5.451 (2) Å | Cell parameters from 25 reflections |
b = 19.493 (1) Å | θ = 6.3–30° |
c = 5.441 (2) Å | µ = 13.50 mm−1 |
β = 100.12 (5)° | T = 150 K |
V = 569.1 (3) Å3 | Transparent, transparent |
Z = 2 | 6 × 2 × 1 mm |
Data collection top
Four circle diffractometer | 1090 reflections with I > 2σ(I) |
Radiation source: spalation source | Rint = 0.013 |
Graphite monochromator | θmax = 47.8°, θmin = 6.3° |
Absorption correction: integration ? | h = −6→6 |
Tmin = ?, Tmax = ? | k = −22→0 |
1116 measured reflections | l = −6→0 |
1093 independent reflections | |
Refinement top
Refinement on F2 | Hydrogen site location: inferred from neighbouring sites |
Least-squares matrix: full | H atoms treated by a mixture of independent and constrained refinement |
R[F2 > 2σ(F2)] = 0.059 | w = 1/[σ2(Fo2) + (0.1358P)2 + 0.0119P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.157 | (Δ/σ)max = 0.001 |
S = 1.20 | Δρmax = 0.16 e Å−3 |
1093 reflections | Δρmin = −0.13 e Å−3 |
272 parameters | Extinction correction: SHELXL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
1 restraint | Extinction coefficient: 6.0 (7) |
Primary atom site location: structure-invariant direct methods | Absolute structure: Flack H D (1983), Acta Cryst. A39, 876-881 |
Secondary atom site location: difference Fourier map | Absolute structure parameter: −10 (10) |
Crystal data top
C4H10Ag2N2O4·2(NO3) | V = 569.1 (3) Å3 |
Mr = 489.90 | Z = 2 |
Monoclinic, P21 | Neutron radiation, λ = 1.17610 Å |
a = 5.451 (2) Å | µ = 13.50 mm−1 |
b = 19.493 (1) Å | T = 150 K |
c = 5.441 (2) Å | 6 × 2 × 1 mm |
β = 100.12 (5)° | |
Data collection top
Four circle diffractometer | 1093 independent reflections |
Absorption correction: integration ? | 1090 reflections with I > 2σ(I) |
Tmin = ?, Tmax = ? | Rint = 0.013 |
1116 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.059 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.157 | Δρmax = 0.16 e Å−3 |
S = 1.20 | Δρmin = −0.13 e Å−3 |
1093 reflections | Absolute structure: Flack H D (1983), Acta Cryst. A39, 876-881 |
272 parameters | Absolute structure parameter: −10 (10) |
1 restraint | |
Special details top
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 (Å2) top | x | y | z | Uiso*/Ueq | |
O1 | 0.4213 (10) | 0.4128 (3) | 0.9219 (9) | 0.0173 (11) | |
O2 | 0.6744 (9) | 0.4337 (3) | 0.6494 (8) | 0.0149 (11) | |
C1 | 0.6096 (8) | 0.4403 (2) | 0.8509 (8) | 0.0137 (9) | |
H1C2 | 0.6658 (16) | 0.5161 (6) | 1.1435 (17) | 0.031 (2) | |
H2C2 | 0.891 (2) | 0.4495 (6) | 1.1705 (19) | 0.035 (2) | |
C2 | 0.7804 (8) | 0.4851 (2) | 1.0399 (7) | 0.0150 (10) | |
N1 | 0.9492 (6) | 0.52952 (17) | 0.9293 (6) | 0.0161 (8) | |
H1N1 | 1.0309 (17) | 0.5055 (5) | 0.800 (2) | 0.028 (2) | |
H2N1 | 0.855 (2) | 0.5710 (6) | 0.8394 (18) | 0.034 (2) | |
H3N1 | 1.0926 (16) | 0.5500 (5) | 1.0633 (16) | 0.027 (2) | |
N2 | −0.4523 (6) | 0.21014 (16) | 0.1072 (6) | 0.0151 (8) | |
H1N2 | −0.5975 (18) | 0.1944 (6) | −0.0251 (19) | 0.035 (2) | |
H2N2 | −0.526 (2) | 0.2357 (6) | 0.238 (2) | 0.038 (2) | |
H3N2 | −0.3671 (17) | 0.1668 (5) | 0.196 (2) | 0.034 (2) | |
C4 | −0.2702 (7) | 0.2534 (2) | −0.0023 (7) | 0.0130 (9) | |
H1C4 | −0.377 (2) | 0.2865 (6) | −0.137 (2) | 0.037 (3) | |
H2C4 | −0.1585 (19) | 0.2191 (6) | −0.0988 (18) | 0.033 (2) | |
C3 | −0.1033 (7) | 0.2961 (2) | 0.1868 (8) | 0.0119 (9) | |
O3 | −0.1684 (9) | 0.3055 (2) | 0.3919 (9) | 0.0148 (10) | |
O4 | 0.0830 (9) | 0.3227 (3) | 0.1148 (9) | 0.0189 (12) | |
N3 | 0.1853 (5) | 0.18050 (17) | −0.4537 (5) | 0.0149 (7) | |
O5 | 0.3390 (9) | 0.2305 (3) | −0.4465 (10) | 0.0208 (11) | |
O6 | 0.1381 (10) | 0.1557 (3) | −0.2572 (11) | 0.0225 (11) | |
O7 | 0.0767 (10) | 0.1576 (3) | −0.6523 (12) | 0.0261 (12) | |
N4 | 0.6826 (6) | 0.05352 (16) | −0.4977 (6) | 0.0161 (7) | |
O8 | 0.5817 (9) | 0.0744 (3) | −0.7049 (10) | 0.0191 (11) | |
O9 | 0.8376 (9) | 0.0052 (3) | −0.4837 (9) | 0.0185 (11) | |
O10 | 0.6294 (9) | 0.0789 (3) | −0.3088 (10) | 0.0236 (13) | |
Ag1 | 0.1053 (9) | 0.3514 (3) | 0.6960 (9) | 0.0178 (11) | |
Ag2 | 0.4037 (8) | 0.3856 (3) | 0.3437 (9) | 0.0168 (11) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O1 | 0.020 (2) | 0.018 (3) | 0.015 (2) | −0.0120 (19) | 0.0068 (17) | −0.0007 (19) |
O2 | 0.016 (2) | 0.020 (3) | 0.010 (2) | −0.0082 (19) | 0.0079 (16) | −0.0078 (18) |
C1 | 0.0174 (19) | 0.011 (2) | 0.0106 (18) | −0.0031 (15) | −0.0037 (14) | −0.0012 (15) |
H1C2 | 0.023 (4) | 0.046 (7) | 0.028 (5) | −0.013 (4) | 0.016 (4) | −0.016 (4) |
H2C2 | 0.031 (5) | 0.044 (6) | 0.027 (5) | −0.001 (4) | −0.006 (4) | 0.013 (5) |
C2 | 0.021 (2) | 0.019 (2) | 0.0040 (17) | −0.0036 (17) | −0.0008 (16) | −0.0039 (17) |
N1 | 0.0241 (16) | 0.0108 (17) | 0.0127 (15) | −0.0022 (14) | 0.0010 (13) | −0.0009 (14) |
H1N1 | 0.029 (5) | 0.021 (5) | 0.038 (6) | −0.007 (4) | 0.014 (4) | −0.006 (4) |
H2N1 | 0.053 (6) | 0.025 (5) | 0.023 (4) | 0.001 (5) | 0.006 (4) | 0.016 (4) |
H3N1 | 0.026 (4) | 0.032 (5) | 0.021 (4) | −0.016 (4) | 0.001 (3) | −0.012 (4) |
N2 | 0.0150 (14) | 0.0128 (17) | 0.0179 (16) | −0.0080 (13) | 0.0040 (14) | 0.0022 (14) |
H1N2 | 0.036 (5) | 0.035 (6) | 0.028 (5) | −0.008 (4) | −0.011 (4) | 0.001 (4) |
H2N2 | 0.048 (6) | 0.028 (5) | 0.044 (6) | 0.004 (5) | 0.022 (5) | −0.009 (5) |
H3N2 | 0.033 (5) | 0.024 (6) | 0.042 (6) | 0.001 (4) | −0.002 (4) | 0.003 (4) |
C4 | 0.0140 (18) | 0.011 (2) | 0.0128 (19) | −0.0084 (16) | −0.0006 (15) | 0.0011 (17) |
H1C4 | 0.045 (6) | 0.032 (6) | 0.027 (5) | −0.011 (5) | −0.011 (4) | 0.009 (5) |
H2C4 | 0.039 (5) | 0.037 (6) | 0.023 (4) | −0.005 (5) | 0.005 (4) | −0.014 (4) |
C3 | 0.0123 (18) | 0.012 (2) | 0.0109 (19) | −0.0033 (15) | 0.0008 (13) | 0.0001 (15) |
O3 | 0.018 (2) | 0.011 (2) | 0.015 (2) | 0.0025 (17) | 0.0002 (17) | −0.0043 (18) |
O4 | 0.021 (2) | 0.021 (3) | 0.013 (2) | −0.007 (2) | −0.0020 (17) | −0.001 (2) |
N3 | 0.0110 (12) | 0.0179 (15) | 0.0153 (14) | 0.0010 (11) | 0.0009 (10) | −0.0034 (12) |
O5 | 0.017 (2) | 0.019 (3) | 0.024 (3) | −0.005 (2) | −0.0023 (17) | 0.000 (2) |
O6 | 0.032 (3) | 0.020 (3) | 0.016 (2) | −0.005 (2) | 0.0066 (19) | −0.002 (2) |
O7 | 0.026 (2) | 0.023 (3) | 0.028 (3) | −0.001 (2) | 0.003 (2) | −0.012 (2) |
N4 | 0.0198 (14) | 0.0145 (16) | 0.0128 (14) | 0.0009 (10) | −0.0006 (11) | 0.0013 (11) |
O8 | 0.020 (2) | 0.014 (2) | 0.021 (3) | −0.0015 (18) | −0.0018 (18) | 0.0061 (19) |
O9 | 0.020 (2) | 0.023 (3) | 0.010 (2) | 0.005 (2) | −0.0043 (15) | 0.0031 (19) |
O10 | 0.017 (2) | 0.035 (3) | 0.019 (3) | 0.000 (2) | 0.0038 (19) | −0.003 (2) |
Ag1 | 0.021 (2) | 0.021 (3) | 0.012 (2) | −0.0084 (19) | 0.0027 (18) | −0.0036 (19) |
Ag2 | 0.012 (2) | 0.022 (3) | 0.016 (2) | −0.0037 (19) | 0.0026 (15) | −0.0017 (19) |
Geometric parameters (Å, º) top
O1—C1 | 1.276 (7) | O4—Ag2 | 2.313 (7) |
O1—Ag1 | 2.273 (7) | O4—Ag1ii | 2.370 (7) |
O1—Ag2i | 2.373 (6) | N3—O7 | 1.222 (7) |
O2—C1 | 1.216 (6) | N3—O6 | 1.241 (7) |
O2—Ag2 | 2.227 (7) | N3—O5 | 1.281 (7) |
C1—C2 | 1.534 (5) | N4—O10 | 1.220 (7) |
C2—N1 | 1.467 (5) | N4—O8 | 1.234 (6) |
N2—C4 | 1.503 (5) | N4—O9 | 1.258 (6) |
C4—C3 | 1.500 (5) | Ag1—O4i | 2.370 (7) |
C3—O3 | 1.243 (7) | Ag1—Ag2 | 2.804 (6) |
C3—O4 | 1.262 (7) | Ag2—O1ii | 2.373 (6) |
O3—Ag1 | 2.213 (7) | | |
| | | |
C1—O1—Ag1 | 129.1 (4) | O7—N3—O5 | 121.2 (5) |
C1—O1—Ag2i | 123.9 (4) | O6—N3—O5 | 120.3 (4) |
Ag1—O1—Ag2i | 104.5 (3) | O10—N4—O8 | 120.1 (5) |
C1—O2—Ag2 | 117.3 (4) | O10—N4—O9 | 120.5 (4) |
O2—C1—O1 | 127.2 (5) | O8—N4—O9 | 119.3 (4) |
O2—C1—C2 | 115.2 (4) | O3—Ag1—O1 | 164.7 (3) |
O1—C1—C2 | 117.5 (4) | O3—Ag1—O4i | 118.8 (3) |
N1—C2—C1 | 114.3 (3) | O1—Ag1—O4i | 76.5 (2) |
C3—C4—N2 | 113.7 (3) | O3—Ag1—Ag2 | 88.9 (2) |
O3—C3—O4 | 126.2 (5) | O1—Ag1—Ag2 | 76.64 (18) |
O3—C3—C4 | 117.6 (4) | O4i—Ag1—Ag2 | 147.9 (2) |
O4—C3—C4 | 116.1 (4) | O2—Ag2—O4 | 164.7 (3) |
C3—O3—Ag1 | 118.0 (4) | O2—Ag2—O1ii | 119.6 (3) |
C3—O4—Ag2 | 128.6 (4) | O4—Ag2—O1ii | 75.7 (2) |
C3—O4—Ag1ii | 125.1 (4) | O2—Ag2—Ag1 | 88.7 (2) |
Ag2—O4—Ag1ii | 103.3 (3) | O4—Ag2—Ag1 | 76.56 (19) |
O7—N3—O6 | 118.5 (5) | O1ii—Ag2—Ag1 | 147.2 (2) |
Symmetry codes: (i) x, y, z+1; (ii) x, y, z−1. |
(gsnrt) Glycine Silver Nitrate
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Crystal data top
C4H10Ag2N2O4·2(NO3) | F(000) = 19 |
Mr = 244.95 | Dx = 2.861 Mg m−3 |
Monoclinic, P21/a | Neutron radiation, λ = 1.17610 Å |
a = 5.451 (5) Å | Cell parameters from 25 reflections |
b = 19.493 (9) Å | θ = 3.4–28.6° |
c = 5.541 (2) Å | µ = 13.38 mm−1 |
β = 100.20 (6)° | T = 293 K |
V = 579.5 (6) Å3 | Transparent, transparent |
Z = 4 | 6 × 2 × 1 mm |
Data collection top
Four circle diffractometer | Rint = 0.028 |
Radiation source: spallation source | θmax = 28.7°, θmin = 3.5° |
Graphite monochromator | h = −2→4 |
333 measured reflections | k = 0→15 |
224 independent reflections | l = −4→4 |
210 reflections with I > 2σ(I) | |
Refinement top
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.158 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.406 | w = 1/[σ2(Fo2) + (0.2P)2] where P = (Fo2 + 2Fc2)/3 |
S = 2.17 | (Δ/σ)max < 0.001 |
224 reflections | Δρmax = 0.10 e Å−3 |
62 parameters | Δρmin = −0.09 e Å−3 |
12 restraints | Extinction correction: SHELXL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 11 (6) |
Crystal data top
C4H10Ag2N2O4·2(NO3) | V = 579.5 (6) Å3 |
Mr = 244.95 | Z = 4 |
Monoclinic, P21/a | Neutron radiation, λ = 1.17610 Å |
a = 5.451 (5) Å | µ = 13.38 mm−1 |
b = 19.493 (9) Å | T = 293 K |
c = 5.541 (2) Å | 6 × 2 × 1 mm |
β = 100.20 (6)° | |
Data collection top
Four circle diffractometer | 210 reflections with I > 2σ(I) |
333 measured reflections | Rint = 0.028 |
224 independent reflections | θmax = 28.7° |
Refinement top
R[F2 > 2σ(F2)] = 0.158 | 12 restraints |
wR(F2) = 0.406 | H atoms treated by a mixture of independent and constrained refinement |
S = 2.17 | Δρmax = 0.10 e Å−3 |
224 reflections | Δρmin = −0.09 e Å−3 |
62 parameters | |
Special details top
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 (Å2) top | x | y | z | Uiso*/Ueq | |
Ag | 0.160 (5) | 0.0164 (10) | −0.175 (4) | 0.062 (9)* | |
O1 | 0.174 (5) | 0.0475 (10) | 0.390 (4) | 0.056 (9)* | |
O2 | 0.424 (5) | 0.0626 (11) | 0.124 (5) | 0.073 (10)* | |
N1 | 0.687 (3) | 0.1603 (6) | 0.406 (2) | 0.062 (8)* | |
C1 | 0.358 (5) | 0.0736 (10) | 0.323 (4) | 0.078 (10)* | |
C2 | 0.523 (4) | 0.1146 (8) | 0.524 (3) | 0.055 (8)* | |
O3 | 0.164 (7) | 0.2098 (12) | 0.171 (5) | 0.085 (11)* | |
O4 | 0.080 (7) | 0.2132 (13) | −0.229 (5) | 0.100 (11)* | |
O5 | −0.097 (6) | 0.1358 (12) | −0.034 (5) | 0.083 (10)* | |
N2 | 0.051 (5) | 0.1851 (8) | −0.033 (4) | 0.085 (9)* | |
H1N | 0.615 (15) | 0.199 (2) | 0.295 (10) | 0.14 (2)* | |
H2N | 0.819 (9) | 0.1812 (18) | 0.538 (8) | 0.084 (15)* | |
H3N | 0.795 (7) | 0.139 (2) | 0.297 (6) | 0.079 (14)* | |
H1C | 0.401 (10) | 0.138 (3) | 0.613 (10) | 0.14 (2)* | |
H2C | 0.589 (15) | 0.081 (2) | 0.657 (9) | 0.14 (2)* | |
Geometric parameters (Å, º) top
Ag—O2 | 2.16 (3) | O2—C1 | 1.24 (2) |
Ag—O1i | 2.32 (3) | N1—C2 | 1.491 (17) |
Ag—O1ii | 2.49 (3) | C1—C2 | 1.512 (19) |
Ag—Agi | 2.89 (6) | O3—N2 | 1.269 (18) |
O1—C1 | 1.233 (19) | O4—N2 | 1.25 (2) |
O1—Agi | 2.32 (3) | O5—N2 | 1.246 (18) |
O1—Agiii | 2.49 (3) | | |
| | | |
O2—Ag—O1i | 161.7 (16) | C1—O2—Ag | 119 (2) |
O2—Ag—O1ii | 119.9 (15) | O1—C1—O2 | 125 (2) |
O1i—Ag—O1ii | 78.3 (12) | O1—C1—C2 | 113 (2) |
O2—Ag—Agi | 88.3 (13) | O2—C1—C2 | 121 (2) |
O1i—Ag—Agi | 74.0 (11) | C1—C2—N1 | 107.7 (14) |
O1ii—Ag—Agi | 146.0 (15) | O5—N2—O4 | 121 (3) |
C1—O1—Agi | 131.0 (19) | O5—N2—O3 | 120 (2) |
C1—O1—Agiii | 124.3 (19) | O4—N2—O3 | 119 (2) |
Agi—O1—Agiii | 101.7 (12) | | |
Symmetry codes: (i) −x, −y, −z; (ii) x, y, z−1; (iii) x, y, z+1. |
Experimental details
| (gsnltc) | (gsnrt) |
Crystal data |
Chemical formula | C4H10Ag2N2O4·2(NO3) | C4H10Ag2N2O4·2(NO3) |
Mr | 489.90 | 244.95 |
Crystal system, space group | Monoclinic, P21 | Monoclinic, P21/a |
Temperature (K) | 150 | 293 |
a, b, c (Å) | 5.451 (2), 19.493 (1), 5.441 (2) | 5.451 (5), 19.493 (9), 5.541 (2) |
β (°) | 100.12 (5) | 100.20 (6) |
V (Å3) | 569.1 (3) | 579.5 (6) |
Z | 2 | 4 |
Radiation type | Neutron, λ = 1.17610 Å | Neutron, λ = 1.17610 Å |
µ (mm−1) | 13.50 | 13.38 |
Crystal size (mm) | 6 × 2 × 1 | 6 × 2 × 1 |
|
Data collection |
Diffractometer | Four circle diffractometer | Four circle diffractometer |
Absorption correction | Integration | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 1116, 1093, 1090 | 333, 224, 210 |
Rint | 0.013 | 0.028 |
θmax (°) | 47.8 | 28.7 |
(sin θ/λ)max (Å−1) | 0.630 | 0.408 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.059, 0.157, 1.20 | 0.158, 0.406, 2.17 |
No. of reflections | 1093 | 224 |
No. of parameters | 272 | 62 |
No. of restraints | 1 | 12 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.16, −0.13 | 0.10, −0.09 |
Absolute structure | Flack H D (1983), Acta Cryst. A39, 876-881 | ? |
Absolute structure parameter | −10 (10) | ? |