A detergent is a surfactant or a mixture of surfactants with cleansing properties when in dilute solutions.[1] There are a large variety of detergents. A common family is the alkylbenzene sulfonates, which are soap-like compounds that are more soluble than soap in hard water, because the polar sulfonate is less likely than the polar carboxylate of soap to bind to calcium and other ions found in hard water.