1. A white crystalline compound of mercury and chlorine (mercurous chloride), formerly used as a laxative and in other medical applications.
Usage: chemistry; medicine; largely historical use

Examples

• Calomel was once a common ingredient in laxative medicines.
• The chemist identified the white powder as calomel based on its crystalline structure.
• Nineteenth-century physicians frequently prescribed calomel for digestive complaints.
• Calomel's use in medicine has declined due to concerns about mercury toxicity.
• The formula for calomel is Hg₂Cl₂.