Perbromate ion is extremely unstable for quantum mechanical reasons. Nitrates are used in making rocket propellants, fertilizers, dynamite, and fireworks. Perchlorate compounds are used in explosives and jet fuels.
Hard water contains high concentrations of calcium ions.
Sodium aluminate is used in fabric printing processes. Hypobromite compounds are used to treat water supplies that are heavily contaminated with bacteria. Nitrite ion is used in bleaching, dyeing and printing fabrics. The NO 4 - ion exists in small quantities in the upper atmosphere.