A wide range of inorganic and mineral compounds are used as flame retardants or as elements of flame retardant systems in combination with bromine, phosphorus, or nitrogen.
The inorganic compounds include those based on nitrogen (melamine compounds), graphite (as used in pencils), silica (as in glass and sand), and inorganic phosphates (ammonium phosphate and polyphosphate).
Mineral compounds include certain phosphates, metal oxides, hydroxides, and other metal products (aluminum, zinc, magnesium, molybdenum, boron, antimony).
Some inorganic and mineral compounds can be used as part of a flame retardant system, in combination with other elements, to achieve fire safety in plastics, foams, textiles, and wood products.