Executive standard: Q/TYÂ·J08.04-2015 English alias: Boric oxide, Boron oxide, Boric anhydride CAS RN: 1303-86-2 1. Physical and chemical properties: 1.1 Molecular formula: B2O3 1.2 Molecular weight: 69.62 1.3 Melting point: 450â�� 1.4 Boiling point:1860â�� 1.5 Density: 1.085 g/mL (Amorphous) 1.6 Solubility: Dissolved in acid, ethanol, hot water, and slightly dissolved in cold water. 1.7 Properties: Colorless crystal powder. Be greasy in the surface. With strong hygroscopicity, it is easy to be hydrolysised to form boric acid. In high temperature, it can be reduced by alkali metal or magnesium to monocrystal boron. It can be completely mixed with the oxides of metal, copper, sliver, aluminum, tin, arsenic.