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Title: Crystal chemistry of M[PO{sub 2}(OH){sub 2}]{sub 2}.2H{sub 2}O compounds (M=Mg, Mn, Fe, Co, Ni, Zn, Cd): Structural investigation of the Ni, Zn and Cd salts

Abstract

The compounds M[PO{sub 2}(OH){sub 2}]{sub 2}.2H{sub 2}O (M=Mg, Mn, Fe, Co, Ni, Zn, Cd) were prepared from super-saturated aqueous solutions at room temperature. Single-crystal X-ray structure investigations of members with M=Ni, Zn, Cd were performed at 295 and 120 K. The space-group symmetry is P2{sub 1}/n, Z=2. The unit-cell parameters are at 295/120 K for M=Ni: a=7.240(2)/7.202(2), b=9.794(2)/9.799(2), c=5.313(1)/5.285(1) A, {beta}=94.81(1)/94.38(1){sup o}, V=375.4/371.9 A{sup 3}; M=Zn: a=7.263(2)/7.221(2), b=9.893(2)/9.899(3), c=5.328(1)/5.296(2) A, {beta}=94.79(1)/94.31(2){sup o}, V=381.5/377.5 A{sup 3}; M=Cd: a=7.356(2)/7.319(2), b=10.416(2)/10.423(3), c=5.407(1)/5.371(2) A, {beta}=93.85(1)/93.30(2){sup o}, V=413.4/409.1 A{sup 3}. Layers of corner-shared MO{sub 6} octahedra and phosphate tetrahedra are linked by three of the four crystallographically different hydrogen bonds. The fourth hydrogen bond (located within the layer) is worth mentioning because of the short O{sub h}...O bond distance of 2.57-2.61 A at room temperature (2.56-2.57 A at 120 K); only for M=Mg it is increased to 2.65 A. Any marked temperature-dependent variation of the unit-cell dimension is observed only vertical to the layers. The analysis of the infrared (IR) spectroscopy data evidences that the internal PO{sub 4} vibrations are insensitive to the size and the electronic configuration of the M {sup 2+} ions. The slight strengthening of the intra-molecular P-O bonds in the Mgmore » salt is caused by the more ionic character of the Mg-O bonds. All IR spectra exhibit the characteristic 'ABC trio' for acidic salts: 2900-3180 cm{sup -1} (A band), 2000-2450 cm{sup -1} (B band) and 1550-1750 cm{sup -1} (C band). Both the frequency and the intensity of the A band provide an evidence that the PO{sub 2}(OH){sub 2} groups in M[PO{sub 2}(OH){sub 2}]{sub 2}.2H{sub 2}O compounds form weaker hydrogen bonds as compared with other acidic salts with comparable O...O bond distances of about 2.60 A. The observed shift of the O-H stretching vibrations of the water molecule in the order M=Mg>Mn{approx}Fe{approx}Co>Ni>Zn{approx}Cd has been discussed with respect to the influence of both the character and the strength of M{r_reversible}H{sub 2}O interactions. - Graphical abstract: IR spectroscopy showed the internal PO{sub 4} vibrations to be insensitive to the size and the electronic configuration of the M {sup 2+} ions and reflect the more ionic character of the Mg-O bonds. The observed 'ABC trio' characteristic for acidic salts is discussed. Single-crystal X-ray investigations were performed at 120 and 295 K. One of the four hydrogen bonds is worth mentioning because of the short O{sub h}...O bond distance of 2.57-2.61 A at room temperature (2.56-2.57 A at 120 K)« less

Authors:
 [1];  [2]
  1. Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Bl.11, 1113 Sofia (Bulgaria), E-mail: vkoleva@svr.igic.bas.bg
  2. Institut fuer Mineralogie und Kristallographie, Universitaet Wien, Althanstrasse 14, A-1090 Vienna (Austria), E-mail: herta.silvia.effenberger@univie.ac.at
Publication Date:
OSTI Identifier:
21015734
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 180; Journal Issue: 3; Other Information: DOI: 10.1016/j.jssc.2006.12.024; PII: S0022-4596(07)00003-5; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; BOND LENGTHS; CADMIUM COMPOUNDS; COBALT COMPOUNDS; ELECTRONIC STRUCTURE; INFRARED SPECTRA; IONS; IRON COMPOUNDS; LATTICE PARAMETERS; LAYERS; MAGNESIUM COMPOUNDS; MANGANESE COMPOUNDS; MONOCLINIC LATTICES; MONOCRYSTALS; NICKEL COMPOUNDS; PHOSPHATES; SPACE GROUPS; TEMPERATURE DEPENDENCE; TEMPERATURE RANGE 0065-0273 K; TEMPERATURE RANGE 0273-0400 K; ZINC COMPOUNDS

Citation Formats

Koleva, Violeta, and Effenberger, Herta. Crystal chemistry of M[PO{sub 2}(OH){sub 2}]{sub 2}.2H{sub 2}O compounds (M=Mg, Mn, Fe, Co, Ni, Zn, Cd): Structural investigation of the Ni, Zn and Cd salts. United States: N. p., 2007. Web. doi:10.1016/j.jssc.2006.12.024.
Koleva, Violeta, & Effenberger, Herta. Crystal chemistry of M[PO{sub 2}(OH){sub 2}]{sub 2}.2H{sub 2}O compounds (M=Mg, Mn, Fe, Co, Ni, Zn, Cd): Structural investigation of the Ni, Zn and Cd salts. United States. doi:10.1016/j.jssc.2006.12.024.
Koleva, Violeta, and Effenberger, Herta. Thu . "Crystal chemistry of M[PO{sub 2}(OH){sub 2}]{sub 2}.2H{sub 2}O compounds (M=Mg, Mn, Fe, Co, Ni, Zn, Cd): Structural investigation of the Ni, Zn and Cd salts". United States. doi:10.1016/j.jssc.2006.12.024.
@article{osti_21015734,
title = {Crystal chemistry of M[PO{sub 2}(OH){sub 2}]{sub 2}.2H{sub 2}O compounds (M=Mg, Mn, Fe, Co, Ni, Zn, Cd): Structural investigation of the Ni, Zn and Cd salts},
author = {Koleva, Violeta and Effenberger, Herta},
abstractNote = {The compounds M[PO{sub 2}(OH){sub 2}]{sub 2}.2H{sub 2}O (M=Mg, Mn, Fe, Co, Ni, Zn, Cd) were prepared from super-saturated aqueous solutions at room temperature. Single-crystal X-ray structure investigations of members with M=Ni, Zn, Cd were performed at 295 and 120 K. The space-group symmetry is P2{sub 1}/n, Z=2. The unit-cell parameters are at 295/120 K for M=Ni: a=7.240(2)/7.202(2), b=9.794(2)/9.799(2), c=5.313(1)/5.285(1) A, {beta}=94.81(1)/94.38(1){sup o}, V=375.4/371.9 A{sup 3}; M=Zn: a=7.263(2)/7.221(2), b=9.893(2)/9.899(3), c=5.328(1)/5.296(2) A, {beta}=94.79(1)/94.31(2){sup o}, V=381.5/377.5 A{sup 3}; M=Cd: a=7.356(2)/7.319(2), b=10.416(2)/10.423(3), c=5.407(1)/5.371(2) A, {beta}=93.85(1)/93.30(2){sup o}, V=413.4/409.1 A{sup 3}. Layers of corner-shared MO{sub 6} octahedra and phosphate tetrahedra are linked by three of the four crystallographically different hydrogen bonds. The fourth hydrogen bond (located within the layer) is worth mentioning because of the short O{sub h}...O bond distance of 2.57-2.61 A at room temperature (2.56-2.57 A at 120 K); only for M=Mg it is increased to 2.65 A. Any marked temperature-dependent variation of the unit-cell dimension is observed only vertical to the layers. The analysis of the infrared (IR) spectroscopy data evidences that the internal PO{sub 4} vibrations are insensitive to the size and the electronic configuration of the M {sup 2+} ions. The slight strengthening of the intra-molecular P-O bonds in the Mg salt is caused by the more ionic character of the Mg-O bonds. All IR spectra exhibit the characteristic 'ABC trio' for acidic salts: 2900-3180 cm{sup -1} (A band), 2000-2450 cm{sup -1} (B band) and 1550-1750 cm{sup -1} (C band). Both the frequency and the intensity of the A band provide an evidence that the PO{sub 2}(OH){sub 2} groups in M[PO{sub 2}(OH){sub 2}]{sub 2}.2H{sub 2}O compounds form weaker hydrogen bonds as compared with other acidic salts with comparable O...O bond distances of about 2.60 A. The observed shift of the O-H stretching vibrations of the water molecule in the order M=Mg>Mn{approx}Fe{approx}Co>Ni>Zn{approx}Cd has been discussed with respect to the influence of both the character and the strength of M{r_reversible}H{sub 2}O interactions. - Graphical abstract: IR spectroscopy showed the internal PO{sub 4} vibrations to be insensitive to the size and the electronic configuration of the M {sup 2+} ions and reflect the more ionic character of the Mg-O bonds. The observed 'ABC trio' characteristic for acidic salts is discussed. Single-crystal X-ray investigations were performed at 120 and 295 K. One of the four hydrogen bonds is worth mentioning because of the short O{sub h}...O bond distance of 2.57-2.61 A at room temperature (2.56-2.57 A at 120 K)},
doi = {10.1016/j.jssc.2006.12.024},
journal = {Journal of Solid State Chemistry},
number = 3,
volume = 180,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}