Sodium Paramolybdate, Na₆Mo₇O₂₄.22H₂O

Sodium Paramolybdate, Na₆Mo₇O₂₄.22H₂O, obtained by dissolving molybdenum trioxide in a slight excess of sodium carbonate, by precipitating a saturated solution of molybdic anhydride in sodium carbonate solution by means of nitric acid, or by interaction of molybdic anhydride and borax solution, forms large efflorescent glassy crystals which readily fuse in their water of crystallisation and become anhydrous at 130° C. It is slightly soluble in cold water, but quite readily so in hot water.