- a hydrate of tungsten trioxide, H2WO4⋅H2O, used in the manufacture of tungsten-lamp filaments.
- any of a group of acids derived from tungsten by the addition of acid to a soluble tungstate or to a mixture of a tungstate and a silicate, phosphate, etc.
- any of various oxyacids of tungsten obtained by neutralizing alkaline solutions of tungstates. They are often polymeric substances, typical examples being H 2 WO 4 (orthotungstic acid), H 2 W 4 O 13 (metatungstic acid), and H 10 W 12 O 14 (paratungstic acid)
