Tungstates and molybdates are natural salts of tungstic and molybdic acids. Structurally, they are similar to phosphates and sulfates as their basic structural units are tetrahedral anionic groups that are not connected to each other. Since the ions of tungsten and molybdenum are similar in size, they can substitute for each other in the mineral structure, leading to the formation of solid solution series. Although these minerals are very rare in nature, they are an important source of tungsten and molybdenum.

Among tungstates, the most well-known are wolframite-a tungsten ore mineral and a mineral used in steel production, and scheelite-also a tungsten ore mineral, while among molybdates, the best known is wulfenite-a mineral important for obtaining molybdenum and steel production.