Ammonium tetrathiomolybdate
（重定向自Ammonium thiomolybdate）
![The [MoS4]2− anion.](/Images/godic/202412/20/MoS41650.png")
Ammonium tetrathiomolybdate is the chemical compound with the formula [NH4]2MoS4. This bright red ammonium salt is an important reagent in the chemistry of molybdenum and has been used as a building block in bioinorganic chemistry. The thiometallate anion has the distinctive property of undergoing oxidation at the sulfur centers concomitant with reduction of the metal from Mo(VI) to Mo(IV).