Thiepane (also hexathiophane) is the organosulfur compound with the formula (CH<sub>2</sub>)<sub>6</sub>S. Thiepanes are seven-membered ring heterocycles that contains sulfide. The parent thiepane has seldom been studied.
A variety of derivatives are known. Hexathiathiepane (CAS RN 17233-71-5, m.p. 90 ðC) is CH<sub>2</sub>S<sub>6</sub>. A naturally occurring derivative is lenthionine, 1,4-(CH<sub>2</sub>)<sub>2</sub>S<sub>5</sub>.
Thiepane itself may be a product of spontaneous coal fires in post-mining waste heaps.