Sodium molybdate, Na₂MoO₄, is useful as a source of molybdenum

Molybdenum

Molybdenum , is a Group 6 chemical element with the symbol Mo and atomic number 42. The name is from Neo-Latin Molybdaenum, from Ancient Greek , meaning lead, itself proposed as a loanword from Anatolian Luvian and Lydian languages, since its ores were confused with lead ores...

. It is often found as the dihydrate, Na₂MoO₄·2H₂O.

The molybdate(VI) anion is tetrahedral. Two sodium cations coordinate with every one anion.
Sodium molybdate was first synthesized by the method of hydration. A more convenient synthesis is done by dissolving MoO₃

Molybdenum(VI) oxide

Molybdenum trioxide is chemical compound with the formula MoO3. This compound is produced on the largest scale of any molybdenum compound. It occurs as the rare mineral molybdite...

 in sodium hydroxide at 50–70 °C and crystallizing the filtered product.