Sodium selenite

Sodium selenite is a chemical compound. Its chemical formula is Na2SeO3. It contains sodium and selenite ions.
Properties.
Sodium selenite is a white solid. It dissolves in water. It is a weak oxidizing agent. It reacts with acids to make selenous acid. It can be oxidized by powerful oxidizing agents to make sodium selenate. 
Preparation.
It is made by reacting sodium hydroxide with selenium dioxide
Uses.
Sodium selenite is used to add a pink color to glass. It is also used in some vitamin supplements. 
Safety.
Eating of any more than a very tiny amount would give selenium poisoning.