Barium iodide

Chemical Properties

Colorless crystals, decomposes and reddens on exposure to air.Soluble in water; slightly soluble in alcohol.

Physical properties

Barium iodide occurs in two forms, one anhydrous and the other as a dihydrate. Both are white solids. This salt is stable, but air and light sensitive. It is also hygroscopic and moisture sensitive. Barium iodide is incompatible with strong oxidizing agents.

Uses

Preparation of other iodides.

Preparation

Barium iodide is made by the neutralization of barium carbonate with HI in water:
BaCO3＋2HI (aq)→BaI2 (aq)
It is also made by the reaction of BaH2 with ammonium iodide in pyridine:
BaH2＋2NH4I (aq)→BaI2 (aq)＋ 2NH3 (gas)＋H2 (gas)
The product crystallizes as the hydrate BaI2·2H2O. If this heated, dehydration to anhydrous BaI2 occurs. The dihydrate dehydrates at 539°C to form BaI2.