Quantum chemical study and low-temperature calorimetry of phase transition in V{sub 4}S{sub 9}Br{sub 4}

• Published in: Journal of solid state chemistry Vol. 181; no. 10
• Main Authors: Kozlova, S.G., Boreskov Institute of Catalysis SB RAS, Novosibirsk 630090, Gabuda, S.P., Berezovskii, G.A., Pischur, D.P., Mironov, Y.V., Simon, A., Fedorov, V.E.
• Format: Journal Article
• Language: English
• Published: United States 15-10-2008
• Subjects: BROMIDES; CALORIMETRY; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; INTERACTIONS; PHASE TRANSFORMATIONS; SULFIDES; SYMMETRY; VANADIUM COMPOUNDS
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/j.jssc.2008.07.013

The phase transition in a mixed-valence tetranuclear compound V{sub 4}S{sub 9}Br{sub 4} was studied by DFT calculations and low-temperature high-precision calorimetry. According to DFT data, the phase transition of the low-temperature modification may be accompanied by C{sub 4v}{yields}C{sub 2v} symmetry lowering and electron spin pairing. A weak exchange-correlation interaction discovered between {mu}{sub 4}-S{sup 2-} and S{sup 2-} ions in V{sub 4}S{sub 9}Br{sub 4} may play an important part in multicentered interactions. Experimental calorimetric data show that the phase transition is a displacive phase transformation. - Graphical abstract: Dysinaptic basins of electron spin pairing in low-temperature phase V{sub 4}S{sub 9}Br{sub 4} (arrows)