Thorium(IV) nitrate tetrahydrate.

Chemical properties

white crystal(s); slightly deliquescent; used in thoriated tungsten filaments and as a reagent for fluoride determination [HAW93] [MER06]

Physical properties

The tetrahydrate is a white crystalline mass; hydgroscopic; decomposes at about 500°C; very soluble in water; soluble in ethanol.

The Uses of Thorium(IV) nitrate tetrahydrate.

Thorium nitrate is a reagent for measuring fluorine and for making thoriated tungsten filaments. Thorium nitrate containing 1% cerium nitrate is the impregnating liquid in making incandescent gas mantles.

Preparation

Thorium nitrate is obtained as an intermediate in making thorium metal from monazite sand. Also, the salt is prepared by heating thorium metal or its oxide or hydroxide with nitric acid, followed by evaporation of the solution and crystallization.

Hazard

Thorium nitrate is highly toxic by ingestion and other routes of exposure. The compound also is a radiation hazard.