二硫化钼，化学式MoS₂。为带有银灰色光泽的黑色六方晶系结晶粉末。

二硫化钼不溶于水、稀酸和浓硫酸，一般不溶于其他酸、碱、有机溶剂中，但溶于热硫酸。400 °C缓慢发生氧化，生成三氧化钼。

可以用钛铁试剂来检验生成的三氧化钼，首先将产物用氢氧化钠或氢氧化钾溶液处理（原理是将三氧化钼转化为钼酸盐），然后滴加钛铁试剂溶液，会和生成的钼酸钠或钼酸钾反应，产生金黄色溶液。这种方法很灵敏，微量的钼酸盐都能被检测出来。而如果没有三氧化钼生成，溶液就不会产生金黄色，因为二硫化钼不和氢氧化钠或氢氧化钾溶液反应。

Molybdenum disulfide is the inorganic compound with the formula MoS
2.

The compound is classified as a metal dichalcogenide. It is a silvery black solid that occurs as the mineral molybdenite, the principal ore for molybdenum. MoS
2 is relatively unreactive. It is unaffected by dilute acids and oxygen. In appearance and feel, molybdenum disulfide is similar to graphite. It is widely used as a solid lubricant because of its low friction properties and robustness. Bulk MoS
2 is a diamagnetic, indirect bandgap semiconductor similar to silicon, with a bandgap of 1.23 eV.