Cobalt(II) hydroxide

Cobaltdihydroxid

Pink powder

Fixed

3.597 g · cm -3 ( 25 ° C)

• Sparingly soluble in water
• Soluble in concentrated alkaline solutions

Attention

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Cobalt ( II) hydroxide is a chemical compound of the cobalt from the group of the hydroxides.

Production and representation

Cobalt ( II ) hydroxide precipitates cobalt ( II) solutions by alkali solutions, depending on the water content than initially unstable blue, later reddish-pink precipitate.

Properties

Cobalt ( II ) hydroxide is not amphoteric, pink solid with a cadmium iodide crystal structure. It decomposes at 168 ° C in vacuum to cobalt (II ) oxide and is oxidized by air to cobalt (III ) hydroxide. Thermal decomposition in air at about 300 ° C yields cobalt ( II, III ) oxide. When stored in air, the brown cobalt ( III ) oxide hydrate forms. Cobalt ( II ) hydroxide is soluble in concentrated alkaline solutions, with deep blue Tetrahydroxo - cobaltate (II ) ions ( [ Co ( OH) 4] 2 - ) form.

With 3Co (OH ) 2.2 H2O, there is also a hydrate. This is a blue powder. Its crystal structure is a hydroxide of existing from the brucite type layers grating in which the layer spacing is expanded by adding an intermediate water layer.

Use

Cobalt (II ) hydroxide is used as an intermediate in the preparation of cobalt.