Strontium hydroxide, Sr(OH)2, 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. Sr(OH)2 exists in anhydrous, monohydrate, or octahydrate form.
| |
| Identifiers | |
|---|---|
 Y | |
3D model (JSmol) |
|
| ChEBI | |
| ChemSpider |
|
| ECHA InfoCard | 100.038.501 
|
| EC Number |
|
| 847042 | |
PubChem CID |
|
| UNII |
Y |
CompTox Dashboard (EPA) |
|
| |
| |
| Properties | |
| Sr(OH)2 | |
| Molar mass | 121.63 g/mol (anhydrous) 139.65 g/mol (monohydrate) 265.76 g/mol (octahydrate) |
| Appearance | prismatic colourless crystals deliquescent |
| Density | 3.625 g/cm3 (anhydrous) 1.90 g/cm3 (octahydrate) |
| Melting point | 535 °C (995 °F; 808 K) (anhydrous, 375K for octahydrate) |
| Boiling point | 710 °C (1,310 °F; 983 K) decomposes (anhydrous) |
| 0.41 g/100 mL (0 °C) 1.77 g/100 mL (40 °C) 21.83 g/100 mL (100 °C) [1] | |
| Solubility | insoluble in acetone soluble in acid, NH4Cl |
| Basicity (pKb) | 0.3 (first OH–), 0.83 (second OH–)[2] |
| −40.0·10−6cm3/mol | |
| Structure | |
| tetragonal (octahydrate) | |
| Hazards | |
| NFPA 704 (fire diamond) | |
| Flash point | Non-flammable |
| Related compounds | |
Other anions |
Strontium oxide Strontium peroxide |
Other cations |
Beryllium hydroxide Magnesium hydroxide Calcium hydroxide Barium hydroxide |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
Because Sr(OH)2 is slightly soluble in cold water, its preparation can be easily carried out by the addition of a strong base such as NaOHorKOH, drop by drop to a solution of any soluble strontium salt, most commonly Sr(NO3)2 (strontium nitrate). The Sr(OH)2 will precipitate out as a fine white powder. From here, the solution is filtered, and the Sr(OH)2 is washed with cold water and dried.[3]
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.
Strontium hydroxide is a severe skin, eye and respiratory irritant. It is harmful if swallowed.
