Strontium hydroxide
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.
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| ECHA InfoCard | 100.038.501 |
| EC Number |
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| 847042 | |
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CompTox Dashboard (EPA) |
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| 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] |
| −40.0·10−6 cm3/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). | |
Preparation Edit
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 NaOH or KOH, 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]
Applications Edit
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 Edit
Strontium hydroxide is a severe skin, eye and respiratory irritant. It is harmful if swallowed.
References Edit
- ^ Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0-07-049439-8
- ^ "Sortierte Liste: pKb-Werte, nach Ordnungszahl sortiert. - Das Periodensystem online" (in German).
- ^ Brauer, Georg (1963). Handbook Of Preparative Inorganic Chemistry. Academic Press. p. 935.