Sulfur (S) powder molar mass 32.1 g/mol Also known as sulfur flowers, brimstone, flores sulphuris, flowers of brimstone A very fine, bright yellow sulfur powder that is produced by sublimation and deposition. Sulfur is a very important chemical as a fungicide, pesticide, bactericide, in pharmaceuticals, fertilizer and especially sulfuric acid, 85% of annual production. It is flammable and toxic. Found naturally in volcanically active areas.