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Title: Vibrational spectra and H-bondings in anhydrous and monohydrate {alpha}-Zr phosphates

Abstract

A new FTIR and FT-Raman investigation on {alpha}-zirconium phosphate (Zr(HPO{sub 4}){sub 2}.H{sub 2}O) and its anhydrous form has been performed in order to obtain an affordable assignment of their vibrational spectra as well as to highlight the hydrogen bonding structure formed by the P-OH groups and the intercalated water molecules. To this end the spectral changes induced by both temperature and isotopic exchange were observed on several high-purity grade samples of different morphology especially prepared and well characterized by SEM, RX, DSC and TGA. In particular, it is also presented as a detailed discussion of the results obtained by FTIR-PAS for different sample morphology. The observed spectra have been analyzed and interpreted according to the {alpha}-Zr(HPO{sub 4}){sub 2}.H{sub 2}O crystal structure and H-bond geometry. The obtained results allowed to clarify the mechanism of the {alpha}-Zr(HPO{sub 4}){sub 2}.H{sub 2}O{sup {yields}}{alpha}-Zr(HPO{sub 4}){sub 2} dehydration process as well as the H-bonding changes involved in the high temperature phase transition of anhydrous {alpha}-Zr(HPO{sub 4}){sub 2}. - Graphical abstract: A detailed analysis of the vibrational spectra of {alpha}-zirconium phosphates allowed to obtain an affordable band assignment highlighting the hydrogen bonding structure formed by the P-OH groups and the intercalated water molecules, the dehydration mechanism andmore » the changes in the interlayer region induced by the {alpha} to {beta} phase transition.« less

Authors:
 [1];  [1];  [1];  [2];  [3]
  1. Dipartimento di Chimica and CEMIN, Centro di Eccellenza Materiali Innovativi Nanostrutturati, Universita di Perugia, Via Elce di Sotto, 8. 06123 Perugia (Italy)
  2. Dipartimento di Chimica e Chimica Industriale, Universita di Genova, Via Dodecaneso 31. 16146 Genova (Italy), E-mail: piaggio@chimica.unige.it
  3. Dipartimento di Chimica e Chimica Industriale, Universita di Genova, Via Dodecaneso 31. 16146 Genova (Italy)
Publication Date:
OSTI Identifier:
21015765
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 180; Journal Issue: 4; Other Information: DOI: 10.1016/j.jssc.2007.01.016; PII: S0022-4596(07)00035-7; 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; AMINO ACIDS; CALORIMETRY; CRYSTAL STRUCTURE; FOURIER TRANSFORMATION; HYDRATES; INFRARED SPECTRA; ISOTOPIC EXCHANGE; MORPHOLOGY; PHASE TRANSFORMATIONS; SCANNING ELECTRON MICROSCOPY; THERMAL GRAVIMETRIC ANALYSIS; ZIRCONIUM PHOSPHATES; ZIRCONIUM-ALPHA

Citation Formats

Casciola, Mario, Donnadio, Anna, Montanari, Francesca, Piaggio, Paolo, and Valentini, Valeria. Vibrational spectra and H-bondings in anhydrous and monohydrate {alpha}-Zr phosphates. United States: N. p., 2007. Web. doi:10.1016/j.jssc.2007.01.016.
Casciola, Mario, Donnadio, Anna, Montanari, Francesca, Piaggio, Paolo, & Valentini, Valeria. Vibrational spectra and H-bondings in anhydrous and monohydrate {alpha}-Zr phosphates. United States. doi:10.1016/j.jssc.2007.01.016.
Casciola, Mario, Donnadio, Anna, Montanari, Francesca, Piaggio, Paolo, and Valentini, Valeria. Sun . "Vibrational spectra and H-bondings in anhydrous and monohydrate {alpha}-Zr phosphates". United States. doi:10.1016/j.jssc.2007.01.016.
@article{osti_21015765,
title = {Vibrational spectra and H-bondings in anhydrous and monohydrate {alpha}-Zr phosphates},
author = {Casciola, Mario and Donnadio, Anna and Montanari, Francesca and Piaggio, Paolo and Valentini, Valeria},
abstractNote = {A new FTIR and FT-Raman investigation on {alpha}-zirconium phosphate (Zr(HPO{sub 4}){sub 2}.H{sub 2}O) and its anhydrous form has been performed in order to obtain an affordable assignment of their vibrational spectra as well as to highlight the hydrogen bonding structure formed by the P-OH groups and the intercalated water molecules. To this end the spectral changes induced by both temperature and isotopic exchange were observed on several high-purity grade samples of different morphology especially prepared and well characterized by SEM, RX, DSC and TGA. In particular, it is also presented as a detailed discussion of the results obtained by FTIR-PAS for different sample morphology. The observed spectra have been analyzed and interpreted according to the {alpha}-Zr(HPO{sub 4}){sub 2}.H{sub 2}O crystal structure and H-bond geometry. The obtained results allowed to clarify the mechanism of the {alpha}-Zr(HPO{sub 4}){sub 2}.H{sub 2}O{sup {yields}}{alpha}-Zr(HPO{sub 4}){sub 2} dehydration process as well as the H-bonding changes involved in the high temperature phase transition of anhydrous {alpha}-Zr(HPO{sub 4}){sub 2}. - Graphical abstract: A detailed analysis of the vibrational spectra of {alpha}-zirconium phosphates allowed to obtain an affordable band assignment highlighting the hydrogen bonding structure formed by the P-OH groups and the intercalated water molecules, the dehydration mechanism and the changes in the interlayer region induced by the {alpha} to {beta} phase transition.},
doi = {10.1016/j.jssc.2007.01.016},
journal = {Journal of Solid State Chemistry},
number = 4,
volume = 180,
place = {United States},
year = {Sun Apr 15 00:00:00 EDT 2007},
month = {Sun Apr 15 00:00:00 EDT 2007}
}
  • Four new Li uranyl phosphates and arsenates have been prepared by high-temperature solid-state reactions: {alpha}-Li[(UO{sub 2})(PO{sub 4})] (1), {alpha}-Li[(UO{sub 2})(AsO{sub 4})] (2), {beta}-Li[(UO{sub 2})(AsO{sub 4})] (3) and Li{sub 2}[(UO{sub 2}){sub 3}(P{sub 2}O{sub 7}){sub 2}] (4). The structures of the compounds have been solved by direct methods: 1-triclinic, P1-bar, a=5.0271(1) A, b=9.8799(2) A, c=10.8920(2) A, {alpha}=108.282(9){sup o}, {beta}=102.993(8){sup o}, {gamma}=104.13(1){sup o}, V=470.69(2) A{sup 3}, Z=4, R{sub 1}=0.0415 for 2786 unique reflections with |F{sub 0}|{>=}4{sigma}{sub F}; 2-triclinic, P1-bar, a=5.129(2) A, b=10.105(3) A, c=11.080(3) A, {alpha}=107.70(2){sup o}, {beta}=102.53(3){sup o}, {gamma}=104.74(3){sup o}, V=501.4(3) A{sup 3}, Z=4, R{sub 1}=0.055 for 1431 unique reflections with |F{submore » 0}|{>=}4{sigma}{sub F}; 3-triclinic, P1-bar, a=5.051(1) A, b=5.303(1) A, c=10.101(1) A, {alpha}=90.31(1){sup o}, {beta}=97.49(1){sup o}, {gamma}=105.08(1){sup o}, V=258.80(8) A{sup 3}, Z=2, R{sub 1}=0.0339 for 2055 unique reflections with |F{sub 0}|{>=}4{sigma}{sub F}; 4-triclinic, P1-bar, a=5.312(1) A, b=6.696(1) A, c=12.542(1) A, {alpha}=94.532(9){sup o}, {beta}=99.059(8){sup o}, {gamma}=110.189(7){sup o}, V=409.17(10) A{sup 3}, Z=2, R{sub 1}=0.0565 for 1355 unique reflections with |F{sub 0}|{>=}4{sigma}{sub F}. The structures of all four compounds are based upon 3-D frameworks of U and T polyhedra (T=P, As). Phases 1 and 2 are isostructural and consist of U{sub 2}O{sub 12} dimers and UO{sub 6} square bipyramids linked by single TO{sub 4} tetrahedra. The structure of 3 consists of 3-D framework of corner-sharing UO{sub 6} bipyramids and AsO{sub 4} tetrahedra. In the structure of 4, the framework is composed of U{sub 2}O{sub 12} dimers, UO{sub 6} bipyramids and P{sub 2}O{sub 7} dimers. In all the compounds, Li{sup +} cations reside in framework cavities. The topologies of the 3-D frameworks can be described as derivatives of the PtS (cooperite) network. - Graphical abstract: Polyhedral and topological presentation of Li{sub 2}[(UO{sub 2}){sub 3}(P{sub 2}O{sub 7}){sub 2}] crystal structure.« less
  • Phase transitions and the mobility of proton-containing groups in hydrogen zirconium phosphate HZr{sub 2}(PO{sub 4}){sub 3}.nH{sub 2}O with the NASICON structure were studied by X-ray powder diffraction, {sup 1}H, {sup 31}P NMR, IR spectroscopy and TG analysis. Heating HZr{sub 2}(PO{sub 4}){sub 3}.H{sub 2}O above 420 K results in dehydration and in a rhombohedral-triclinic phase transition. Continued heating to about 490 K results in the thermal activation of cation disordering and phase transition of HZr{sub 2}(PO{sub 4}){sub 3} from triclinic to rhombohedral phase. Parameter 'a' of HZr{sub 2}(PO{sub 4}){sub 3} lattice decreases during the heating. It is shown that oxonium ionsmore » in HZr{sub 2}(PO{sub 4}){sub 3}.H{sub 2}O are characterized by high rotation and translation mobility. Rotation mobility of oxonium ions can be increased by the substitution of zirconium by yttrium or niobium.« less
  • Structure transformations and proton conductivity of hydrogen zirconium phosphates with the NASICON structure, H{sub 1{+-}X}Zr{sub 2-X}M{sub X}(PO{sub 4}){sub 3}.H{sub 2}O (X = 0, 0.02 and 0.1, M = Nb, Y), were studied by X-ray powder diffraction, calorimetry, IR- and impedance spectroscopy. Substitution of zirconium by niobium leads to decrease of the lattice parameters, while yttrium doping leads to their increase. H{sub 0.9}Zr{sub 1.9}Nb{sub 0.1}(PO{sub 4}){sub 3} structure was determined at 493 and 733 K. This phase crystallizes in rhombohedral space group R3-bar c with lattice parameters a = 8.8564(5) A, c = 22.700(1) A at 493 K and a =more » 8.8470(2) A, c = 22.7141(9) A at 733 K. The a parameter and lattice volume were found to decrease with temperature increasing. Structure transformations upon heating are caused mainly by the decrease of the M1 site and C cavities. Ion conductivity of obtained materials was found to increase in humid atmosphere. Activation energies of conductivity were calculated. Rhombohedral-triclinic phase transition found by X-ray powder diffraction was proved by calorimetry data. According to XRD and IR spectroscopy data hydrogen bond in HZr{sub 2}(PO{sub 4}){sub 3} was found to be weaker than in hydrated material.« less
  • Ammonium pertechnetate dissolves slightly in anhydrous hydrogen fluoride to give solutions of pertechnetyl fluoride. Raman spectra of the solutions as well as infrared and Raman spectra of the pure compound indicate that TcO/sub 3/F has symmetry C/sub 3v/ with the following assignments (in cm/sup -1): (a/sub 1/) 696, 962, 317; (e) 951, 347, 231. A comparison with other MO/sub 3/X compounds indicates a necessity to reverse some of the original assignments. (auth)