Barium sulfate is a white powder in crystal shape.

Barium sulfate crystal hydrate should be barium sulfate pentahydrate, BaSO4 · 5H2O, gypsum is divided into two types, raw gypsum is 2caso4 · H2O, and anhydrite is CaSO4 · 2H2O.

Although barium sulfate is hardly soluble in water, this does not mean that there is no crystal and hydrate. The raw gypsum is CaSO4 · 2H2O. After heating for a period of time, part of the crystal water is lost to form mature gypsum: CaSO4 · 0.5h2o. Add water to restore CaSO4 · 2H2O.

Assay

Accurately weigh about 0.6g of this product, put it into a platinum crucible, add 10g of anhydrous sodium carbonate, mix it, burn it until it melts, continue to heat it for 30 minutes, cool it, put the crucible into a 400ml beaker, add 250ml of water, stir it with a glass rod, heat it until the melt elutes from the crucible. Remove the crucible from the beaker, wash it with water, put the washing solution into the beaker, continue to wash the inside of the crucible with 2ml of 6mol / L acetic acid solution, then wash it with water, and combine the washing solution into the beaker.