STUDY OF ACID PYRIDINE-3-CARBOXYLIC ACID DODECATUNGSTENPHOSPHATE OF THE COMPOSITION (C
6NO
2H
5)
2Н[PW
12O
40]×2Н
2О
a:2:{s:4:"TYPE";s:4:"HTML";s:4:"TEXT";s:157:"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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