A bromate ion is represented by the chemical formula BrO3-, where the three is written in subscript and the minus sign is written above it in superscript. The ion contains one atom of bromine, as shown by the symbol Br, three atoms of oxygen and a charge of minus one.
A bromate ion is formed by the reaction between a bromide ion with a minus one charge and ozone, which is a molecule containing three atoms of oxygen. Bromate is considered a carcinogen and is dangerous when found in drinking water and other edible products. The bromate ion can combine with other ions to make a molecule such as barium bromate.