The Difference Between Oxide and Dioxide

Oxide and Dioxide are Chemical Compounds

An oxide is a chemical compound that contains at least one oxygen atom and one atom of another chemical element. Iron oxide (rust) is a chemical compound of iron and oxygen.

Oxides form when oxygen reacts with other chemical elements.  The reaction can be due to combustion, oxidation or another chemical process.

Dioxide is an oxide that contains two oxygen atoms plus an atom of another chemical element.  Carbon dioxide is a chemical compound of two oxygen atoms and one carbon atom.

Another example is silicon dioxide also known as silica.  Silicon dioxide is found in nature as the mineral quartz.