Phase ratios in Na/sub 2/O-CaO-V/sub 2/O/sub 5/ system

The phase composition of the Na/sub 2/O-CaO-V/sub 2/O/sub 5/ system is studied. The existance of two new compounds - binary metavanadate Na/sub 2/Ca(VO/sub 3/)/sub 4/ and binary pyrovanadateNa/sub 4/Ca/sub 12/(V/sub 2/O/sub 7/)/sub 7/ is found. It is shown that Na/sub 4/Ca/sub 12/(V/sub 2/O/sub 7/)/sub 7/ and Ca/sub 2/V/sub 2/O/sub 7/ interaction brings about Na/sub 2/Ca(VO/sub 3/)/sub 4/ and Ca/sub 3/(VO/sub 4/)/sub 2/ formation. The mechanism of formation of solid solutions on the base of NaVO/sub 3/, Ca(VO/sub 3/)/sub 2/ and Ca/sub 3/(VO/sub 4/)/sub 2/ is considered.