sulph(o)- (US sulf(o)-).
[Latin sulfur, sulphur.]
Sulphurous acid forms sulphites, while sulphuric acid forms sulphates. Sulphonic acid is an organic acid containing the group -SO2OH, which forms sulphonates; the process of conversion of compounds into sulphonates is sulphonation. Sulphides are compounds of sulphur with another component, usually a metallic element. See also thio-.