Compounds having the structure RC(=S=O)H. (Also known by the disapproved term @S06108@ which includes thioaldehyde S-oxides and thioketone S-oxides).
Source: PAC, 1995, 67, 1307. (Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)) on page 1372 [Terms] [Paper]