Potassium chromate
Potassium chromate is the inorganic compound with the formula (K2CrO4. This yellow solid is the potassium salt of the chromate anion. It is a common laboratory chemical, whereas sodium chromate is important industrially. It is a class two carcinogen.
Structure
Two crystalline forms are known, both being very similar to the corresponding potassium sulfate. Orthorhombic β-K2CrO4 is the common form, but it converts to an α-form above 66 °C. These structures are complex, although the sulfate adopts the typical tetrahedral geometry.
Structure of β-K2CrO4.
Structure of β-K2CrO4.
Coordination sphere of one of two types of K+ site.
Coordination sphere of one of two types of K+ site.
The environment about the tetrahedral CrO42- center in β-K2CrO4.
The environment about the tetrahedral CrO42- center in β-K2CrO4.
Production and reactions
It is prepared by treating potassium dichromate with potassium hydroxide.
In solution, the behavior of potassium and sodium dichromates are very similar. When treated with lead(II) nitrate, it gives an orange-yellow precipitate, lead(II) chromate.
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