Mercurous vanadate

Chemically pure vanadium pentoxide is alternatively prepared by precipitating insoluble mercurous vanadate, HgV03, from a neutral solution of a vanadate, and distilling off the mercury, or by ignition of vanadium salts of volatile acids, for example, vanadium oxytrichloride, VOCl3. The oxide also results from the oxidation of any of the lower oxides, or by the electrolysis of a solution of sodium vanadate or copper vanadate, using a divided cell the last method yields a product of 98 per cent, purity.2... 

Gravimetric Methods.—The vanadium compound is converted into sodium vanadate by fusion or other method, and after separation from other salts (e.g. arsenate, molybdate, phosphate, chromate, tungstate) is precipitated from nearly neutral solution either as (a) mercurous vanadate or (b) basic lead vanadate. In (a), mercurous... 

Aqueous Hg2 precipitates yellow mercurous vanadate, Hg2(V03)2. This has been used gravimetrically, with ignition to V2O5. 

Occluded hydrogen is more reactive chemically than the normal gas. Hydrogenated palladium precipitates mercury and mercurous chloride from an aqueous solution of the dichloride, without any evolution of hydrogen. It reduces ferric salts to ferrous potassium ferricyanide to ferrocyanide chlorine water to hydrochloric add iodine water to hydriodic acid 2 chromates to chromic salts ceric to cerous salts whilst cupric, stannic, arsenic, manganic, vanadic, and molybdic compounds are also partially reduced.3... 

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