Acidic oxide

Acidic oxides are oxides of nonmetals. They can also be termed as inorganic chemicals that react with water to form an acid; or react with a base to form a salt. Acidic oxides are oxides of either nonmetals or of metals in high oxidation states. They are formed when a nonmetal burns. Their chemistry can be systematically understood by taking an oxoacid and removing water from it, until only the oxide is left. The resulting oxide belongs to this group of substances.

Acidic oxides are not Arrhenius acids, nor are they Brønsted–Lowry acids, since they neither accept protons, nor do they increase the hydrogen ion concentration of water. However, they are Lewis acids, since they accept electron pairs from certain Lewis bases, most notably Base anhydrides.^[1]

Examples

• Carbon dioxide, which reacts with water to form carbonic acid.
• Sulfur dioxide, which does not react with water to form the non-existent sulfurous acid but does react with bases to form sulfites.
• Silicon dioxide, which does not react with water but does react with bases to form silicates.
• Chromium trioxide, which reacts with water to form chromic acid.
• Phosphorus pentoxide, which reacts with water to form phosphoric acid.
• Dinitrogen pentoxide, which reacts with water to form nitric acid.
• Sulfur trioxide, which reacts with water to form sulfuric acid.
• Manganese heptoxide, which reacts with water to form permanganic acid.

See also

• Organic acid anhydride, similar compounds in organic chemistry
• Base anhydride

References

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