Melamine is pure white monoclinic prism crystal, tasteless, with a density of 1.573g/cm3 (16 ℃). Atmospheric pressure melting point 354 ℃ (decomposition); Rapid heating sublimation, sublimation temperature 300 ℃. The solubility in water increases with the increase of temperature. At 20 ℃, it is about 3.3 g / L, which is slightly soluble in cold water, hot water, very slightly soluble in hot ethanol, insoluble in ether, benzene and carbon tetrachloride, and soluble in methanol, formaldehyde, hot ethylene glycol, acetic acid, glycerol, pyridine, etc. Low toxicity. It is generally stable, but it may decompose and release cyanide at high temperature, and release nitrogen that does not support combustion at the same time, so it can be used as a flame retardant.