21. In 1841, a chemist named Robert Oxland gave the first procedures for preparing tungsten trioxide and sodium tungstate . 22. "' Sodium tungstate "'is the inorganic compound with the formula Na 2 WO 4. 23. The structure of cubic zirconium tungstate consists of corner-sharing ZrO 6 octahedral and WO 4 tetrahedral structural units. 24. "' Russellite "'is a bismuth tungstate mineral with the chemical formula Bi 2 WO 6. 25. Zirconium tungstate has the unusual property of shrinking in all dimensions when heated, whereas most other substances expand when heated. 26. In this respect vanadium shows similarities to tungstate and molybdate, whereas chromium however has a more limited range of ions. 27. When high energy photons strike lead tungstate , they make it glow, or scintillate, and this glow can be measured. 28. "' Raspite "'is a mineral, a lead tungstate ; with the dimorph of the tetragonal stolzite. 29. Double tungstates of the form A 2 B 2 ( WO 4 ) 3 are predicted to exist in the langbeinite form. 30. Predominance diagrams can become very complicated when many polymeric species can be formed, such as in vanadates, molybdates, and tungstates .
