Barium chloride

Barium chloride is a chemical substance. It is among the most important salts of barium. It is soluble in water. It is a poison. When it is heated, it gives a yellow or green color to the flame. It is hygroscopic, meaning that it attracts water from the air. It is mainly used to purify brine but applications include fireworks. 
Barium chloride is toxic. Sodium sulfate may be an antidote.