STUDY OF ACID PYRIDINE-3-CARBOXYLIC ACID DODECATUNGSTENPHOSPHATE OF THE COMPOSITION (C
6NO
2H
5)
2Н[PW
12O
40]Г—2Н
2О
G.Z. Kaziev1, O.A. Kirichenko1, A.I. Stash2, H. Quinones Saul3, E.A. Solov’eva1, Y.S. Chen4
1Moscow State Pedagogical University, Moscow, Russia
2L.Ya. Karpov Institute of Physical Chemistry, Moscow, Russia
3UAM, Ascapotzalco, Mexico
4The University of Chicago, Chicago, Illinois, United States
Keywords: гетерополисоединения, рентгеноструктурный анализ, физико-химические свойства, heteropolycompounds, X-ray crystallography, physicochemical properties
Abstract
Acid pyridine-3-carboxylic acid dodecatungstenphosphate (С
6NO
2H
5)
2H[PW
12O
40]×2Н
2О is synthesized. The compound is studied by chemical analysis, IR spectroscopy, X-ray crystallography, and thermogravimetry. The compound is found to crystallize at 290 K in a hexagonal crystal system (sp. gr. R -3) (I) with the unit cell parameters: а = 33.015(6) Å, с = 12.010(2) Å, g = 120°, V = 11337(4) Å
3, Z = 9. When the temperature decreases to 100 K, a phase transition is observed leading to an increase in symmetry to R -3 m (II), with the unit cell parameters: а = 33.072(1) Å, с = 24.234(1) Å, g = 120°, V = 22955(2) Å
3, Z = 18.
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