Strontium hydroxide, , is a caustic alkali composed of one strontium ion and two hydroxide ions. It is synthesized by combining a strontium salt with a strong base. exists in anhydrous, monohydrate, heptahydrate, and octahydrate form.

Preparation

Because is only slightly soluble in cold water, its preparation can be easily carried out by the addition of a strong base such as NaOH or KOH drop by drop to a solution of any soluble strontium salt, most commonly (strontium nitrate), which forms the octahydrate. This must be done in the absence of to prevent formation of the nearly insoluble carbonate which would complicate purification:

The will precipitate out as a fine white powder. From here, the solution is filtered, and the is washed with a large excess of ice cold water and dried.

The anhydrous form or any of the hydrates may be prepared by adding one molar equivalent of water to strontium oxide (SrO). The hydrates may be prepared by adding the required amount of water (one, seven, or eight more molar equivalents) to the anhydrous form.

Applications

Strontium hydroxide is used chiefly in the refining of beet sugar and as a stabilizer in plastic. It may be used as a source of strontium ions when the chlorine from strontium chloride () is undesirable. Strontium hydroxide absorbs carbon dioxide () from the air to form strontium carbonate ().

Safety

Strontium hydroxide is a severe skin, eye and respiratory irritant. It is harmful if swallowed.

References