Acidic oxide

An acidic oxide (sometimes known as an acidic anhydride, but not to be confused with an acid anhydride) is an oxide that either

• reacts with water to form an acid; or
• reacts with a base to form a salt.

Examples include:

• Carbon dioxide which reacts with water to produce carbonic acid.
• Sulfur dioxide, which does not form the non-existent sulfurous acid but does react with bases to form sulfites.
• Silicon dioxide, which does not react with water but will react with bases to form silicates
• Chromium trioxide, which reacts with water to form chromic acid. Chromic acid is a hypothetical acid. The monomer and dimer would respectively have structures similar to sulfuric and disulfuric acids.

Acidic oxides are oxides of either nonmetals or of metals in high oxidation states.

References

• Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Oxford: Butterworth-Heinemann. ISBN 0080379419.