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Chromate Salt Chromate Minerals

Jun 08, 2017

Chromate Salt Chromate minerals

(Chromate) containing chromate CrO42- salts are generally yellow, silver dichromate was dark red. Alkali metal and magnesium chromate such as sodium chromate, potassium chromate, magnesium chromate and so are soluble in water, other alkaline earth metal and heavy metal chromate are not soluble in water. Have a strong oxidative effect. When acidified in solution, it is converted to dichromate and the color changes from yellow to orange. Barium chromate and lead chromate are used as yellow pigments. Soluble chromates are often used as oxidants and used as tanning agents. Can be prepared from chromite.

The chromate mineral is a salt of a metal element cation and a chromate compound. Chromium is a variable element that appears in nature in different valences and forms different minerals. due to

In nature, most of the chromium involved in the composition of oxides and chromium-containing silicate, and the composition of chromate minerals and the number of species are few. The current information has not yet more than ten kinds. The most significant feature of chromate minerals is the distinctive color. Usually yellow, orange or brown, and green in copper. Hardness is generally not high, between 2-3. The proportion is generally between 2-3. Chromate minerals are often formed under the weathering conditions of the product, found in the oxide zone of the deposit.

Material nature editor

1, chromate with oxidation, reduction CrVI often get blue and green CrIII.

2, aqueous solution, chromate ion (yellow) and dichromic acid

Chromate standard solution

Chromate standard solution

Root ions (orange) are in balance. Add acid to promote the formation of dichromate ions, the solution was red; plus alkali is to balance the left shift, the solution was yellow:

2 CrO42- + 2 H + ⇌ Cr2O72- + H2O

3, chromate can be used to determine the chemical oxygen demand in the water (COD).

4, heavy metals, lanthanides and alkaline earth metal chromate mostly soluble or insoluble in water, rarely used. The solubility of alkali metal chromates is relatively large.

5, chromate conversion film can be used to prevent metal corrosion and enhance the adhesion of the coating.

6, pyridinium chlorochromate in organic synthesis for the oxidation of alcohol for the aldehyde.

Long-term exposure to chromate in labor can lead to lung cancer.