The powder is reddish brown powder. When the temperature is higher than 700 ℃, it is easy to oxidize, and the temperature below 700 ℃ is stable. It does not react with any acid except HF, and is insoluble in alkali and water. Soluble in a mixed acid of dilute hydrofluoric acid and nitric acid. The brittle structure of silicon monoxide is dense. When the temperature is higher than 1180 ℃, it is an unstable state and easily disproportionates into Si and SiO. When heated in the air, white silica powder is generated. Mixing silicon dioxide powder with a purity of 99.5% and coal pitch powder (or silicon powder) at a ratio of C/SiO2=1.3 or Si/SiO2=1.2, put them into an electrically heated vacuum furnace, and inject non-oxidizing gas (such as argon) , Hydrogen and other gases), react at high temperature to produce ultrafine (below 0.1/μm) amorphous silicon oxide. Very active. Solid silicon monoxide can be used as an insulating material. It has important value as a fine ceramic raw material. It can also be evaporated in a vacuum and coated on metal mirrors used in optical instruments as a protective film. It can also be used to make semiconductor materials. It is also used for optical glass.