Mercury chloride
From PyroGuide
Synonyms Calomel, Mercurous chloride.
Formula: Hg2Cl2
Description: Mercury(I)chloride is a dense yellowish-white solid that was once used as a chlorine donor for enriching colour, but owing to it's high toxicity and relatively low chlorine content (15%) when compared to the likes of polyvinyl chloride and parlon, it hasn't been widely used in around 40 years.
Hazards: Mercury(I)chloride is toxic and precautions should be taken to minimise exposure by any route.
Hazard Symbols: Xn