Strontium hydroxide

Strontianhydrat

Colorless and odorless crystals

Fixed

3.63 g · cm -3 ( anhydrous) 1.90 g · cm -3 ( octahydrate )

375 ° C ( anhydrous)

Decomposition at 710 ° C

• Poorly in water (20 g · l-1 at 20 ° C)
• Insoluble in acetone

Risk

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Strontium hydroxide is the hydroxide of alkaline earth metal strontium. The molecular formula is Sr (OH ) 2

Representation

Strontium hydroxide can be represented by the reaction of strontium with water. The result is strontium hydroxide and hydrogen.

In addition, strontium hydroxide is formed under excessive heat by the reaction of strontium with water.

Because of its poor solubility of the octahydrate can be (at best the nitrate or chloride salt because of their high solubility ) are shown from any strontium salt by the addition of a strong base such as sodium hydroxide or potassium hydroxide in an aqueous solution by precipitation.

Properties

The salt forms colorless, transparent crystals. In the crystal structure of strontium each Sr2 ion of seven OH - ions surrounded at an average distance of 2.6 angstroms.

When dissolved in water is a medium strong base strontium. It takes in this state, carbon dioxide ( CO2) from the air to form strontium carbonate. Strontium hydroxide is more soluble in water than the hydroxides of calcium and magnesium. It is less toxic than barium.

The octahydrate crystallizes in the tetragonal crystal system in space group P4/ncc with lattice constants a = 901.7 pm and c = 1160.3 pm. On heating, the output of the crystal water takes place in three stages - first it forms a hexahydrate, then a monohydrate and finally the anhydrate, which also crystallizes in the tetragonal crystal system.

Use

Strontium hydroxide is an agent for regulating the pH - value in depilatories. Strontium previously has been used in the sugar industry for cleaning of the molasses.