polysulfides

https://doi.org/10.1351/goldbook.P04754
Compounds R–[S]n–R , with a chain of sulfur atoms (\(n\geq 2\)) and RH. Some chemists exclude disulfides, RS2R , from the class polysulfides.
Source:
PAC, 1995, 67, 1307. 'Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)' on page 1360 (https://doi.org/10.1351/pac199567081307)