Sodium zincate refers to anionic zinc oxides or hydroxides, depending on conditions. In the applications of these materials, the exact formula is not necessarily important and it is likely that aqueous zincate solutions consist of mixtures.

Hydroxyzincates

Solutions of sodium zincate

Zincate

In chemistry the term zincate may refer to* a salt containing Zn42−,also called the tetrahydroxozincate ion. It is an ore of Zinc. Examples include calcium zincate CaZn4.2H2O or Na2Zn4 or the polymeric anion [Zn3−] in for example NaZn3· H2O * an alkali solution prepared from dissolving zinc...

 may be prepared by dissolving zinc

Zinc

Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...

, zinc hydroxide

Zinc hydroxide

Zinc hydroxide Zn2 is an inorganic chemical compound. It also occurs naturally as 3 rare minerals: wülfingite , ashoverite and sweetite ....

, or zinc oxide

Zinc oxide

Zinc oxide is an inorganic compound with the formula ZnO. It is a white powder that is insoluble in water. The powder is widely used as an additive into numerous materials and products including plastics, ceramics, glass, cement, rubber , lubricants, paints, ointments, adhesives, sealants,...

 in an aqueous solution of sodium hydroxide. Simplified equations for these complex processes are:

ZnO + H₂O + 2 NaOH → Na₂Zn(OH)₄

Zn + 2 H₂O + 2 NaOH → Na₂Zn(OH)₄ + H₂

From such solutions, one can crystallize salts of containing the anions Zn(OH)₄^2-, Zn₂(OH)₆^2-, and Zn(OH)₆^4-. Na₂Zn(OH)₄ consists of tetrahedral zincate ion and octahedral sodium cations.
The salt Sr₂Zn(OH)₆ features zinc in an octahedral coordination sphere.

Oxozincates

Related oxides are also known such as Na₂ZnO₂, Na₂Zn₂O₃,, Na₁₀Zn₄O₉.