Strontium hydroxide, Sr(OH)₂, is a caustic

alkali In chemistry, an alkali (; from the Arabic word , ) is a basic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a soluble base has a pH greater than 7.0. The a ...

composed of one

strontium Strontium is a chemical element; it has symbol Sr and atomic number 38. An alkaline earth metal, it is a soft silver-white yellowish metallic element that is highly chemically reactive. The metal forms a dark oxide layer when it is exposed to ...

ion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convent ...

and two

hydroxide Hydroxide is a diatomic anion with chemical formula OH−. It consists of an oxygen and hydrogen atom held together by a single covalent bond, and carries a negative electric charge. It is an important but usually minor constituent of water. It ...

ions. It is synthesized by combining a strontium

salt In common usage, salt is a mineral composed primarily of sodium chloride (NaCl). When used in food, especially in granulated form, it is more formally called table salt. In the form of a natural crystalline mineral, salt is also known as r ...

with a

strong base In chemistry, there are three definitions in common use of the word "base": '' Arrhenius bases'', '' Brønsted bases'', and '' Lewis bases''. All definitions agree that bases are substances that react with acids, as originally proposed by G. ...

. Sr(OH)₂ exists in

anhydrous A substance is anhydrous if it contains no water. Many processes in chemistry can be impeded by the presence of water; therefore, it is important that water-free reagents and techniques are used. In practice, however, it is very difficult to achie ...

, monohydrate, or octahydrate form.

Preparation

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 Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula . It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly corrosive base and alkali t ...

or KOH, drop by drop to a solution of any soluble strontium salt, most commonly Sr(NO₃)₂ (

strontium nitrate Strontium nitrate is an inorganic compound composed of the elements strontium, nitrogen and oxygen with the formula Sr( NO3)2. This colorless solid is used as a red colorant and oxidizer in pyrotechnics. Preparation Strontium nitrate is typica ...

). 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.

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 Chlorine is a chemical element; it has Symbol (chemistry), symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between ...

from

strontium chloride Strontium chloride (SrCl2) is a salt of strontium and chloride. It is a "typical" salt, forming neutral aqueous solutions. As with all compounds of strontium, this salt emits a bright red colour in flame, and is commonly used in fireworks to that ...

is undesirable. Strontium hydroxide absorbs

carbon dioxide Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at norma ...

from the air to form

strontium carbonate Strontium carbonate (SrCO3) is the carbonate salt of strontium that has the appearance of a white or grey powder. It occurs in nature as the mineral strontianite. Chemical properties Strontium carbonate is a white, odorless, tasteless powder ...

Safety

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

References

External links

*http://www.chemicalland21.com/industrialchem/inorganic/STRONTIUM%20HYDROXIDE.htm {{Authority control Strontium compounds Hydroxides