Most halogenoacetates of alkali salts readily undergo a thermally induced polymerization reaction to poly-(hydroxyacetic acid) in the solid state. The lithium salts represent a remarkable exception. The crystal structures of lithium chloroacetate, lithium bromoacetate and lithium iodoacetate were determined ab initio from synchrotron powder diffraction data. The three compounds are isostructural and differ considerably from the structures of sodium chloroacetate and silver chloroacetate, two compounds that undergo polymerization. Most likely, the strong polarizing effect of the small lithium cation is responsible for the unfavorable crystal structure in which each lithium cation is coordinated to four O atoms from four different halogenoacetate molecules. Lithium chloroacetate: a = 9.3882 (9), b = 4.8452 (4), c = 9.0119 (7) Å, β = 94.330 (5)°; lithium bromoacetate: a = 9.7165 (11), b = 4.8610 (6), c = 9.0228 (11) Å, β = 93.946 (5)°; lithium iodoacetate: a = 10.1812 (10), b = 4.8922 (8), c = 9.0468 (10) Å, β = 93.251 (5)°, all crystallizing in space group P21/c with Z = 4.
Supporting information
| Crystallographic Information File (CIF) Contains datablocks global, cl, br, i |
| Rietveld powder data file (CIF format) Contains datablock br |
| Rietveld powder data file (CIF format) Contains datablock cl |
| Rietveld powder data file (CIF format) Contains datablock i |
CCDC references: 134773; 134774; 134775
For all compounds, cell refinement: FULLPROF; program(s) used to refine structure: FULLPROF.
(cl) chloroacetic acid, lithium salt
top
Crystal data top
C2H2ClLiO2 | Z = 4 |
Mr = 100.43 | Melting point: 483.7 K |
Monoclinic, P21/c | Synchrotron radiation, λ = 1.2841 Å |
a = 9.3882 (9) Å | T = 298 K |
b = 4.8452 (4) Å | Particle morphology: platelets |
c = 9.0119 (7) Å | colorless |
β = 94.330 (5)° | cylinder, ? × ? × ? mm |
V = 408.76 (6) Å3 | |
Data collection top
HASYLAB (Hamburg, Germany), Beamline B2 diffractometer | Scan method: step |
Germanium monochromator | 2θmin = 6°, 2θmax = 60°, 2θstep = 0.01° |
Refinement top
Rp = 3.25 | Profile function: Pseudo-Voigt |
Rwp = 4.21 | |
Rexp = 1.88 | Background function: Fixed background |
χ2 = 5.018 | Preferred orientation correction: March's function |
5938 data points | |
Crystal data top
C2H2ClLiO2 | β = 94.330 (5)° |
Mr = 100.43 | V = 408.76 (6) Å3 |
Monoclinic, P21/c | Z = 4 |
a = 9.3882 (9) Å | Synchrotron radiation, λ = 1.2841 Å |
b = 4.8452 (4) Å | T = 298 K |
c = 9.0119 (7) Å | cylinder, ? × ? × ? mm |
Data collection top
HASYLAB (Hamburg, Germany), Beamline B2 diffractometer | 2θmin = 6°, 2θmax = 60°, 2θstep = 0.01° |
Scan method: step | |
Refinement top
Rp = 3.25 | χ2 = 5.018 |
Rwp = 4.21 | 5938 data points |
Rexp = 1.88 | |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
Cl(1) | 0.3600 (7) | 0.139 (1) | 0.1519 (7) | 0.108 | |
O(1) | 0.112 (1) | 0.316 (2) | 0.962 (1) | 0.005 | |
O(2) | 0.098 (2) | −0.051 (3) | 0.826 (1) | 0.005 | |
C(1) | 0.148 (2) | 0.089 (3) | 0.933 (2) | 0.005 | |
C(2) | 0.279 (2) | −0.093 (3) | 0.008 (2) | 0.005 | |
Li(1) | −0.007 (4) | 0.583 (7) | 0.856 (4) | 0.005 | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Cl(1) | 0.026 (1) | 0.097 (2) | 0.021 (1) | 0.022 (1) | −0.008 (1) | −0.014 (1) |
Geometric parameters (Å, º) top
Cl(1)—C(2) | 1.84 | Li(1)—O(1) | 1.91 |
C(1)—C(2)i | 1.62 | Li(1)—O(1)ii | 2.03 |
C(1)—O(1) | 1.19 | Li(1)—O(2)iii | 1.91 |
C(1)—O(2) | 1.24 | Li(1)—O(2)iv | 2.06 |
| | | |
C(1)i—C(2)i—C(1) | 102.7 | O(1)—Li(1)—O(1)ii | 93.5 |
O(1)—C(1)—O(2) | 125.5 | O(2)iii—Li(1)—O(2)iv | 111.7 |
C(2)i—C(1)—O(1) | 129.6 | O(1)—Li(1)—O(2)iii | 113.9 |
C(2)i—C(1)—O(2) | 104.7 | O(1)—Li(1)—O(2)iv | 112.3 |
Symmetry codes: (i) x, y, z+1; (ii) −x, −y+1, −z+2; (iii) −x, y+1/2, −z+3/2; (iv) x, y+1, z. |
(br) bromoacetic acid, lithium salt
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Crystal data top
C2H2BrLiO2 | Z = 4 |
Mr = 144.88 | Melting point: 478.5 K |
Monoclinic, P21/c | Synchrotron radiation, λ = 1.2841 Å |
a = 9.7165 (11) Å | T = 298 K |
b = 4.8610 (6) Å | Particle morphology: platelets |
c = 9.0228 (11) Å | colorless |
β = 93.946 (5)° | cylinder, ? × ? × ? mm |
V = 425.15 (9) Å3 | |
Data collection top
HASYLAB (Hamburg, Germany), Beamline B2 diffractometer | Scan method: step |
Germanium monochromator | 2θmin = 6°, 2θmax = 61°, 2θstep = 0.01° |
Refinement top
Rp = 4.76 | Profile function: Pseudo-Voigt |
Rwp = 6.18 | |
Rexp = 2.76 | Background function: Fixed background |
χ2 = 5.018 | Preferred orientation correction: March's function |
6701 data points | |
Crystal data top
C2H2BrLiO2 | β = 93.946 (5)° |
Mr = 144.88 | V = 425.15 (9) Å3 |
Monoclinic, P21/c | Z = 4 |
a = 9.7165 (11) Å | Synchrotron radiation, λ = 1.2841 Å |
b = 4.8610 (6) Å | T = 298 K |
c = 9.0228 (11) Å | cylinder, ? × ? × ? mm |
Data collection top
HASYLAB (Hamburg, Germany), Beamline B2 diffractometer | 2θmin = 6°, 2θmax = 61°, 2θstep = 0.01° |
Scan method: step | |
Refinement top
Rp = 4.76 | χ2 = 5.018 |
Rwp = 6.18 | 6701 data points |
Rexp = 2.76 | |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
Br(1) | 0.3679 (3) | 0.1644 (7) | 0.1544 (5) | 0.058 | |
O(1) | 0.102 (1) | 0.305 (4) | 0.969 (2) | 0.004 | |
O(2) | 0.089 (2) | −0.067 (3) | 0.824 (2) | 0.004 | |
C(1) | 0.140 (3) | 0.070 (5) | 0.921 (3) | 0.004 | |
C(2) | 0.269 (2) | −0.083 (5) | 0.010 (3) | 0.004 | |
Li(1) | 0.000 (5) | 0.60 (1) | 0.858 (6) | 0.004 | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Br(1) | 0.009 (1) | 0.051 (1) | 0.016 (1) | 0.009 (1) | −0.009 (1) | −0.009 (1) |
Geometric parameters (Å, º) top
Br(1)—C(2) | 1.97 | Li(1)—O(1) | 1.99 |
C(1)—C(2)i | 1.62 | Li(1)—O(1)ii | 1.97 |
C(1)—O(1) | 1.29 | Li(1)—O(2)iii | 1.99 |
C(1)—O(2) | 1.18 | Li(1)—O(2)iv | 1.85 |
| | | |
Br(1)i—C(2)i—C(1) | 111.9 | O(1)—Li(1)—O(1)ii | 91.4 |
O(1)—C(1)—O(2) | 129.7 | O(2)iii—Li(1)—O(2)iv | 114.1 |
C(2)i—C(1)—O(1) | 117.8 | O(1)—Li(1)—O(2)iii | 119.6 |
C(2)i—C(1)—O(2) | 112.3 | O(1)—Li(1)—O(2)iv | 106.5 |
Symmetry codes: (i) x, y, z+1; (ii) −x, −y+1, −z+2; (iii) −x, y+1/2, −z+3/2; (iv) x, y+1, z. |
(i) iodoacetic acid, lithium salt
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Crystal data top
C2H2ILiO(2) | Z = 4 |
Mr = 191.88 | Melting point: 530.2 K |
Monoclinic, P21/c | Synchrotron radiation, λ = 1.2006 Å |
a = 10.1812 (10) Å | T = 298 K |
b = 4.8922 (8) Å | Particle morphology: platelets |
c = 9.0468 (10) Å | colorless |
β = 93.251 (5)° | cylinder, ? × ? × ? mm |
V = 449.89 (10) Å3 | |
Data collection top
HASYLAB (Hamburg, Germany), Beamline B2 diffractometer | Scan method: step |
Germanium monochromator | 2θmin = 6°, 2θmax = 50°, 2θstep = 0.01° |
Refinement top
Rp = 5.64 | Profile function: Pseudo-Voigt |
Rwp = 7.40 | |
Rexp = 3.65 | Background function: Fixed background |
χ2 = 4.121 | Preferred orientation correction: March's function |
4401 data points | |
Crystal data top
C2H2ILiO(2) | β = 93.251 (5)° |
Mr = 191.88 | V = 449.89 (10) Å3 |
Monoclinic, P21/c | Z = 4 |
a = 10.1812 (10) Å | Synchrotron radiation, λ = 1.2006 Å |
b = 4.8922 (8) Å | T = 298 K |
c = 9.0468 (10) Å | cylinder, ? × ? × ? mm |
Data collection top
HASYLAB (Hamburg, Germany), Beamline B2 diffractometer | 2θmin = 6°, 2θmax = 50°, 2θstep = 0.01° |
Scan method: step | |
Refinement top
Rp = 5.64 | χ2 = 4.121 |
Rwp = 7.40 | 4401 data points |
Rexp = 3.65 | |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
I(1) | 0.3739 (4) | 0.181 (2) | 0.1504 (8) | 0.120 | |
O(1) | 0.106 (5) | 0.32 (1) | 0.953 (7) | 0.038 | |
O(2) | 0.078 (3) | −0.07 (1) | 0.831 (6) | 0.038 | |
C(1) | 0.127 (8) | 0.07 (2) | 0.94 (1) | 0.038 | |
C(2) | 0.249 (5) | −0.09 (1) | 0.039 (9) | 0.038 | |
Li(1) | 0.01 (1) | 0.51 (4) | 0.81 (2) | 0.038 | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
I(1) | 0.006 (1) | 0.28 (1) | −0.004 (1) | 0.012 (4) | −0.009 (1) | −0.013 (6) |
Geometric parameters (Å, º) top
I(1)—C(2) | 2.07 | Li(1)—O(1) | 1.78 |
C(1)—C(2)i | 1.68 | Li(1)—O(1)ii | 2.63 |
C(1)—O(1) | 1.21 | Li(1)—O(2)iii | 1.63 |
C(1)—O(2) | 1.33 | Li(1)—O(2)iv | 2.14 |
| | | |
I(1)i—C(2)i—C(1) | 110.2 | O(1)—Li(1)—O(1)ii | 82.0 |
O(1)—C(1)—O(2) | 121.7 | O(2)iii—Li(1)—O(2)iv | 116.9 |
C(2)i—C(1)—O(1) | 125.0 | O(1)—Li(1)—O(2)iii | 133.9 |
C(2)i—C(1)—O(2) | 111.1 | O(1)—Li(1)—O(2)iv | 107.8 |
Symmetry codes: (i) x, y, z+1; (ii) −x, −y+1, −z+2; (iii) −x, y+1/2, −z+3/2; (iv) x, y+1, z. |
Experimental details
| (cl) | (br) | (i) |
Crystal data |
Chemical formula | C2H2ClLiO2 | C2H2BrLiO2 | C2H2ILiO(2) |
Mr | 100.43 | 144.88 | 191.88 |
Crystal system, space group | Monoclinic, P21/c | Monoclinic, P21/c | Monoclinic, P21/c |
Temperature (K) | 298 | 298 | 298 |
a, b, c (Å) | 9.3882 (9), 4.8452 (4), 9.0119 (7) | 9.7165 (11), 4.8610 (6), 9.0228 (11) | 10.1812 (10), 4.8922 (8), 9.0468 (10) |
β (°) | 94.330 (5) | 93.946 (5) | 93.251 (5) |
V (Å3) | 408.76 (6) | 425.15 (9) | 449.89 (10) |
Z | 4 | 4 | 4 |
Radiation type | Synchrotron, λ = 1.2841 Å | Synchrotron, λ = 1.2841 Å | Synchrotron, λ = 1.2006 Å |
Specimen shape, size (mm) | Cylinder, ? × ? × ? | Cylinder, ? × ? × ? | Cylinder, ? × ? × ? |
|
Data collection |
Data collection method | HASYLAB (Hamburg, Germany), Beamline B2 | HASYLAB (Hamburg, Germany), Beamline B2 | HASYLAB (Hamburg, Germany), Beamline B2 |
Specimen mounting | ? | ? | ? |
Data collection mode | ? | ? | ? |
Scan method | Step | Step | Step |
2θ values (°) | 2θmin = 6 2θmax = 60 2θstep = 0.01 | 2θmin = 6 2θmax = 61 2θstep = 0.01 | 2θmin = 6 2θmax = 50 2θstep = 0.01 |
|
Refinement |
R factors and goodness of fit | Rp = 3.25, Rwp = 4.21, Rexp = 1.88, χ2 = 5.018 | Rp = 4.76, Rwp = 6.18, Rexp = 2.76, χ2 = 5.018 | Rp = 5.64, Rwp = 7.40, Rexp = 3.65, χ2 = 4.121 |
No. of data points | 5938 | 6701 | 4401 |
No. of parameters | ? | ? | ? |
No. of restraints | ? | ? | ? |
Selected geometric parameters (Å, º) for (cl) topCl(1)—C(2) | 1.84 | Li(1)—O(1) | 1.91 |
C(1)—C(2)i | 1.62 | Li(1)—O(1)ii | 2.03 |
C(1)—O(1) | 1.19 | Li(1)—O(2)iii | 1.91 |
C(1)—O(2) | 1.24 | Li(1)—O(2)iv | 2.06 |
| | | |
C(1)i—C(2)i—C(1) | 102.7 | O(1)—Li(1)—O(1)ii | 93.5 |
O(1)—C(1)—O(2) | 125.5 | O(2)iii—Li(1)—O(2)iv | 111.7 |
C(2)i—C(1)—O(1) | 129.6 | O(1)—Li(1)—O(2)iii | 113.9 |
C(2)i—C(1)—O(2) | 104.7 | O(1)—Li(1)—O(2)iv | 112.3 |
Symmetry codes: (i) x, y, z+1; (ii) −x, −y+1, −z+2; (iii) −x, y+1/2, −z+3/2; (iv) x, y+1, z. |
Selected geometric parameters (Å, º) for (br) topBr(1)—C(2) | 1.97 | Li(1)—O(1) | 1.99 |
C(1)—C(2)i | 1.62 | Li(1)—O(1)ii | 1.97 |
C(1)—O(1) | 1.29 | Li(1)—O(2)iii | 1.99 |
C(1)—O(2) | 1.18 | Li(1)—O(2)iv | 1.85 |
| | | |
Br(1)i—C(2)i—C(1) | 111.9 | O(1)—Li(1)—O(1)ii | 91.4 |
O(1)—C(1)—O(2) | 129.7 | O(2)iii—Li(1)—O(2)iv | 114.1 |
C(2)i—C(1)—O(1) | 117.8 | O(1)—Li(1)—O(2)iii | 119.6 |
C(2)i—C(1)—O(2) | 112.3 | O(1)—Li(1)—O(2)iv | 106.5 |
Symmetry codes: (i) x, y, z+1; (ii) −x, −y+1, −z+2; (iii) −x, y+1/2, −z+3/2; (iv) x, y+1, z. |
Selected geometric parameters (Å, º) for (i) topI(1)—C(2) | 2.07 | Li(1)—O(1) | 1.78 |
C(1)—C(2)i | 1.68 | Li(1)—O(1)ii | 2.63 |
C(1)—O(1) | 1.21 | Li(1)—O(2)iii | 1.63 |
C(1)—O(2) | 1.33 | Li(1)—O(2)iv | 2.14 |
| | | |
I(1)i—C(2)i—C(1) | 110.2 | O(1)—Li(1)—O(1)ii | 82.0 |
O(1)—C(1)—O(2) | 121.7 | O(2)iii—Li(1)—O(2)iv | 116.9 |
C(2)i—C(1)—O(1) | 125.0 | O(1)—Li(1)—O(2)iii | 133.9 |
C(2)i—C(1)—O(2) | 111.1 | O(1)—Li(1)—O(2)iv | 107.8 |
Symmetry codes: (i) x, y, z+1; (ii) −x, −y+1, −z+2; (iii) −x, y+1/2, −z+3/2; (iv) x, y+1, z. |