Compounds having two
β-haloalkyl groups bound to a sulfur atom, as in
(XC2H2C2H2)2S, and their analogues, the nitrogen (and phosphorus) mustards,
(XC2H2C2H2)2NR.
Compounds having one β-haloalkyl group and one
β-hydroxyalkyl group on
S
are termed hemi- or semi-mustards by some chemists.
Source:
PAC, 1995, 67, 1307
(Glossary of class names of organic compounds and reactivity intermediates based on
structure (IUPAC Recommendations 1995))
on page 1350