Is strontium hydroxide a solid?

Strontium hydroxide is an inorganic compound with the formula Sr(OH)₂ and a molecular weight of 121.63. It is a colorless square crystal system plate or columnar crystal. As an important strontium containing compound, it is very widely used.

Physicochemical properties of strontium hydroxide

Strontium hydroxide is a colorless crystal or white powder. Density is 1.9g/cm3, melting point is 375℃, boiling point is 710℃ (decomposition). It absorbs carbon dioxide into carbonates in the air and can lose seven molecules of crystalline water in dry air. Soluble in hot water and acid, also soluble in ammonium chloride solution, soluble in cold water.

Sr is an alkaline earth metal, and the solubility of strontium hydroxide in water is between calcium hydroxide and barium hydroxide. Although its solubility is not large, it is a strong base with the commonness of alkali. It is completely ionized in water and has corrosive properties. The alkalinity is between calcium hydroxide and barium hydroxide. Industrial and laboratory commonly used soluble salt of strontium (strontium chloride, strontium nitrate, etc.) and concentrated sodium hydroxide solution at room temperature, can precipitate colorless crystal of strontium hydroxide octahydrate.

There are three kinds of strontium hydroxide hydrates, monohydrate and octahydrate. Octhydrate is a colorless tetragonal transparent delix crystal, corrosive. Hydrates become anhydrous by heating and dehydration. When exposed to air, carbon dioxide is absorbed to form strontium carbonate and strontium bicarbonate.

Strontium hydroxide is slightly soluble in cold water and easily soluble in hot water. Its solubility in water varies greatly with temperature, so it can be separated from calcium hydroxide and barium hydroxide by crystallization in aqueous solution. It is soluble in acid and ammonium chloride solutions, but insoluble in acetone. It can form insoluble complexes with glycerol and sucrose and insoluble metal soaps with organic acids.

Preparation of strontium hydroxide

Strontium nitrate, strontium chloride or strontium sulfide react with sodium hydroxide saturated solution, cooling crystallization precipitation of octuhydrate, and then filtration, heating dehydration to obtain anhydrous strontium hydroxide.

When pure strontium oxide is moistened with a theoretical amount of water, it causes a violent reaction and gives off heat to produce white powdered strontium hydroxide. The addition of water forms strontium hydroxide monohydrate, heptahydrate and octahydrate. Strontium bishydrate is insoluble. It can also be prepared from a soluble strontium salt reinforced base. When heated to 100℃, it becomes anhydrous substance. Greater solubility than calcium hydroxide, especially at high temperatures. Anhydrous strontium hydroxide is a colorless powder with a relative density of 3.62. Strong hygroscopicity. Heat to 701℃ to transform into SrO. The solubility in 100g water is 0.8g (20℃), 17.4g (40℃), 21.8g (100℃). It absorbs CO2 in the air and turns it into carbonate.

Application of strontium hydroxide

1. Strontium hydroxide is widely used in the refining of beet sugar in Europe. It becomes an insoluble disaccharide salt, which is separated and refined.

2. Also used as a stabilizer of polyethylene plastic;

3. Can be used to improve the dryness of dry oil and paint;

4. Used for preparation of strontium lubricating wax and various strontium salts.