strontium hydroxide



Strontium hydroxide, Sr(OH)2, is a caustic
alkali In chemistry, an alkali (; from ar, القلوي, al-qaly, lit=ashes of the saltwort) is a basic, ionic 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 s ...
composed of one
strontium Strontium is the chemical element with the symbol Sr and atomic number 38. An alkaline earth metal, strontium is a soft silver-white yellowish metallic element that is highly chemically reactive. The metal forms a dark oxide layer when it is e ...
ion 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 wate ...
ions. It is synthesized by combining a strontium
salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quantiti ...
with a
strong base In chemistry, there are three definitions in common use of the word base, known as Arrhenius bases, Brønsted bases, and Lewis bases. All definitions agree that bases are substances that react with acids, as originally proposed by G.-F. R ...
. 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 achi ...
, monohydrate, or octahydrate form.


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 NaOH. It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly caustic base and alkali ...
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.


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 with the 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 them. Chlorine ...
from strontium chloride is undesirable. Strontium hydroxide absorbs
carbon dioxide Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is tr ...
from the air to form strontium carbonate.


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


External links

* {{Authority control Strontium compounds Hydroxides