Arsenic Suboxide, As₂O

Arsenic Suboxide (?), As₂O, was considered by Berzelius to constitute the superficial dark brown film which forms on arsenic owing to oxidation. Retgers stated that the brown deposit which accompanies the mirror formed by sublimation of commercial arsenic was the suboxide. It was looked upon as an intermediate product in the oxidation of arsenic, but the material so described was undoubtedly a mixture of arsenic and arsenious oxide or, in some cases, merely the amorphous variety of arsenic.