An oxoacid is an acid formed by the reaction of a non-metal oxide with water, in which the ionisable hydrogen is attached to oxygen. Such acids are very common and include many of the familiar mineral acids. Carbonic acid (H₂CO₃), formed when carbon dioxide dissolves in water, is an oxoacid.

含氧酸是由非金属氧化物与水反应生成的酸,其中可电离的氢与氧相连。这类酸非常普遍,包括许多常见的无机酸。二氧化碳溶于水生成的碳酸(H₂CO₃)就是一种含氧酸。