Mercury(II) iodide is a chemical compound with the molecular formula HgI?. It is typically produced synthetically but can also be found in nature as the extremely rare mineral coccinite. Unlike the related mercury(II) chloride it is hardly soluble in water. Wikipedia Formula: HgI2 Molar mass: 454.4 g/mol Melting point: 498.2°F (259°C) Boiling point: 662°F (350°C) Density: 6.36 g/cm³ Colors: scarlet-red Mercury(II) iodide is used for preparation of Nessler's reagent, used for detection of presence of ammonia. Mercury(II) iodide is a semiconductor material, used in some x-ray and gamma ray detection and imaging devices operating at room temperatures.[5] In veterinary medicine, mercury(II) iodide is used in blister ointments in exostoses, bursal enlargement,