Lead orthovanadate

Figure 35. Domain texture in /J-lead orthovanadate resulting from the ->P transformation...

The orthovanadate ion [V04]3- occurs only at very high pH. It is such a strong base that the first step in its protonation, forming [HV04]2 , is already complete at pH —12. When the pH is gradually lowered to —1 successive protonation ultimately leads to the formation of the pale yellow cationic species, usually formulated as V02... 

Lead Orthovanadaie, Pb3(V04)2, is precipitated as a white powder when sodium orthovanadate is treated with lead acetate solution.7... 

Formal substitution of three OH groups in hypothetical orthovanadic acid H3V04[0= V(0H)3] for halide leads to the trihalides VOX3 (X = F, Cl, Br). The corresponding nitrate V0(N03)3 is aiso known. The oxovanadium trihalides can add an additional... 

Triple orthovanadates containing a divalent cation, trivalent rare earth, and tetravalent thorium or cerium, have been studied by Nabar et al. (1981 and 1983). The samples were prepared by mixing soluble compounds of the corresponding elements in water, evaporating the solution and heating at SOO C. The compounds MRTh(V04)3, where M = Ca, Cd, crystallize with the tetragonal zircon structure and those where M = Ba with the monoclinic monazite structure. Strontium and lead compounds show dimorphism (Nabar and Mhatre, 1982). 

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