Simple Binary and Related Compounds

Simple Binary and Related Compounds.—Oxides. The information presently available concerning the crystal structures and properties of vanadium oxides has been tabulated. 

A phase diagram has been proposed for the V-VO system from m.p., d.t.a., X-ray, and other studies. In this system V9O4, V2O, and V4O have been identified at 510. 1185. and 1665°C. respectively, and the m.p, of VO was determined as 1790 The cubic vanadium monoxide phase has been shown to exhibit two closely related phase sections. VO — 091 os— 1.25- 

The formation of gaseous VO by the flash photolysis of VOCI3 has been reported. and some new transitions have been identified in the electronic absorption spectrum of this oxide. 

Studies of the V20a-V204 system have confirmed that the phases V 02 i ( = 2—9) exist below 1400°C. ° The crystal structure of V4O7 has been shown to be based on the rutile lattice, the VOg octahedra being considerably distorted with V—O = 178—212 pm. The heat and entropy of formation of Vj Ojj at 1333 K have been determined as —373 kJmol and 146Jmol K respectively, by electrochemical measurements.  

Takada, Y. Bando, K. Kosuge, H. Okinaka, and K. Nagasawa, Proceedings of the International Conference on Ferrites, 1970, 563. 

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Simple Binary and Related Compounds.—Reviews have been published which describe crystal structures of, and chemical bonding in, the Ta-O system. Structural aspects of niobium and tantalum oxides and oxide fluorides have... 

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