Thiosulfoxides are orthogonally isomeric with disulfides, having the second sulfur branching from the first and not partaking in a continuous chain, i.e. >S=S rather than −S−S−.
Disulfide bonds are analogous but more common than related peroxide, thioselenide, and diselenide bonds. Intermediate compounds of these also exist, for example thioperoxides (also known as oxasulfides) such as hydrogen thioperoxide, have the formula ROSR (equivalently RSOR). These are isomeric to sulfoxides in a similar manner to the above; i.e. >S=O rather than −S−O−.
Thiuram disulfides, with the formula (RNCSS), are disulfides but they behave distinctly because of the thiocarbonyl group.
Compounds with three sulfur atoms, such as CHS−S−SCH, are called trisulfides, or trisulfide bonds.