I2 is a metallic gray solid at room temperature. It is slightly soluble in water. Its melting point is 113.7 ̊C (236.66 ̊F), boiling point 184.3 ̊C (363.74 ̊F), density 4.933 g/cm3. Iodine is an important nutrition. Iodine can also be used for sterilization. The iodine tincture which is made of iodine and potassium iodide solved in alcohol have a strong usage to kill pathogens. Iodine gas has a violet color.