Crystal structure of a new polytype in the V-P-O system:: is ω-VOPO4 a dynamically stabilised metastable network?

被引:24
作者
Amorós, P
Marcos, MD
Roca, M
Alamo, J
Beltrán-Porter, A
Beltrán-Porter, D
机构
[1] Univ Valencia, Inst Ciencia Mat, ICMUV, Valencia 46071, Spain
[2] Univ Politecn Valencia, Dept Quim, Valencia 46071, Spain
关键词
D O I
10.1016/S0022-3697(01)00054-3
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
omega -VOPO4 has been prepared by thermal decomposition of different oxovanadium hydrogen phosphates, namely VO(HPO4) nH(2)O (n = 2(alpha), 2(beta) and 4) and beta -NH4(VO2)(HPO4). The omega -VOPO4 phase only remains well crystallised at relatively high temperatures. Its crystal structure has been determined ab initio from X-ray powder diffraction data collected at 4750C. The cell is tetragonal (space group P4(2)/mmc) with a = 4.8552(3) Angstrom and c = 8.4301(6) Angstrom. Starting positional parameters were obtained by direct methods, and the structure was refined using Rietveld profile refinement principles. Disorder of two oxygen sublattices is observed. To rationalise some features of the crystal structure of this new phase, a dynamic model is proposed and discussed. (C) 2001 Elsevier Science Ltd. All rights reserved.
引用
收藏
页码:1393 / 1399
页数:7
相关论文
共 20 条
[1]   OXOVANADIUM(IV) HYDROGEN PHOSPHATE HYDRATES - A TIME-RESOLVED NEUTRON POWDER DIFFRACTION STUDY [J].
AMOROS, P ;
IBANEZ, R ;
BELTRAN, A ;
BELTRAN, D ;
FUERTES, A ;
GOMEZROMERO, P ;
HERNANDEZ, E ;
RODRIGUEZCARVAJAL, J .
CHEMISTRY OF MATERIALS, 1991, 3 (03) :407-413
[2]  
AMOROS P, 1988, EUR J SOL STATE INOR, V25, P599
[3]   New trends in V-P-O solids [J].
Amorós, P ;
Marcos, MD ;
Beltrán-Porter, A ;
Beltrán-Porter, D .
CURRENT OPINION IN SOLID STATE & MATERIALS SCIENCE, 1999, 4 (02) :123-131
[4]   NEW VANADYL HYDROGENPHOSPHATE HYDRATES - ELECTRONIC-SPECTRA OF THE VO2+ ION IN THE VO(HXPO4)XYH2O SYSTEM [J].
AMOROS, P ;
IBANEZ, R ;
MARTINEZTAMAYO, E ;
BELTRANPORTER, A ;
BELTRANPORTER, D ;
VILLENEUVE, G .
MATERIALS RESEARCH BULLETIN, 1989, 24 (11) :1347-1360
[5]  
AMOROS P, 1994, MRS SERIES, V346, P811
[6]  
BELTRANPORTER D, 1991, EUR J SOL STATE INOR, V28, P131
[7]  
CASACARANO G, 1992, ACTA CRYSTALLAOGR A, V48, P859
[8]   VANADYL PYROPHOSPHATE - A CRITICAL OVERVIEW [J].
CENTI, G .
CATALYSIS TODAY, 1993, 16 (01) :5-26
[9]   MECHANISTIC ASPECTS OF MALEIC-ANHYDRIDE SYNTHESIS FROM C4-HYDROCARBONS OVER PHOSPHORUS VANADIUM-OXIDE [J].
CENTI, G ;
TRIFIRO, F ;
EBNER, JR ;
FRANCHETTI, VM .
CHEMICAL REVIEWS, 1988, 88 (01) :55-80
[10]   ROLE OF ION-EXCHANGE IN SOLID-STATE CHEMISTRY [J].
CLEARFIELD, A .
CHEMICAL REVIEWS, 1988, 88 (01) :125-148