Mercury(II) chloride, also known as mercuric chloride, 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 toxicity and is used in various applications, including as a disinfectant and in the preparation of other mercury compounds. In addition to its industrial uses, mercury(II) chloride has historical significance in medicine, although its use has declined due to safety concerns. It is important to handle this substance with care, as exposure can lead to serious health issues, including poisoning.