Mercuric chloride, also known as mercury(II) chloride or calomel, is a chemical compound with the formula HgCl2. It appears as a white crystalline solid and is highly soluble in water. This compound is known for its toxic properties and has been used historically in various applications, including as a disinfectant and in the production of other mercury compounds. Due to its toxicity, exposure to mercuric chloride can lead to serious health issues, including damage to the kidneys and nervous system. Today, its use is highly regulated, and safer alternatives are often preferred in medical and industrial applications. Proper handling and disposal are essential to prevent environmental contamination.