Strontium chloride

Strontium chloride

Names
IUPAC name Strontium chloride
Other names Strontium(II) chloride
Identifiers
CAS Number	10476-85-4 Y 10025-70-4 (hexahydrate) Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:36383 Y
ChEMBL	ChEMBL2219640 N
ChemSpider	55440 Y
ECHA InfoCard	100.030.870
EC Number	233-971-6
PubChem CID	61520
UNII	EKE8PS9J6Z Y O09USB7Z44 (hexahydrate) Y
CompTox Dashboard (EPA)	DTXSID6040616
InChI InChI=1S/2ClH.Sr/h2*1H;/q;;+2/p-2 Y Key: AHBGXTDRMVNFER-UHFFFAOYSA-L Y InChI=1S/2ClH.Sr/h2*1H;/q;;+2/p-2 Key: AHBGXTDRMVNFER-UHFFFAOYSA-L
SMILES [Sr+2].[Cl-].[Cl-]
Properties
Chemical formula	SrCl2
Molar mass	158.53 g/mol (anhydrous) 266.62 g/mol (hexahydrate)
Appearance	White crystalline solid
Density	3.052 g/cm3 (anhydrous, monoclinic form) 2.672 g/cm3 (dihydrate) 1.930 g/cm3 (hexahydrate)
Melting point	874 °C (1,605 °F; 1,147 K) (anhydrous) 61 °C (hexahydrate)
Boiling point	1,250 °C (2,280 °F; 1,520 K) (anhydrous)
Solubility in water	anhydrous: 53.8 g/100 mL (20 °C) hexahydrate: 106 g/100 mL (0 °C) 206 g/100 mL (40 °C)
Solubility	ethanol: very slightly soluble acetone: very slightly soluble ammonia: insoluble
Magnetic susceptibility (χ)	−63.0·10−6 cm3/mol
Refractive index (nD)	1.650 (anhydrous) 1.594 (dihydrate) 1.536 (hexahydrate)[1]
Structure
Crystal structure	Deformed rutile structure
Coordination geometry	octahedral (six-coordinate)
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	Irritant
NFPA 704 (fire diamond)	2 0 0
Flash point	N/A
Related compounds
Other anions	Strontium fluoride Strontium bromide Strontium iodide
Other cations	Beryllium chloride Magnesium chloride Calcium chloride Barium chloride Radium chloride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

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 effect. Its properties are intermediate between those for barium chloride, which is more toxic, and calcium chloride.

Strontium chloride can be prepared by treating aqueous strontium hydroxide or strontium carbonate with hydrochloric acid:

Sr(OH)₂ + 2 HCl → SrCl₂ + 2 H₂O

Crystallization from cold aqueous solution gives the hexahydrate, SrCl₂·6H₂O. Dehydration of this salt occurs in stages, commencing above 61 °C (142 °F). Full dehydration occurs at 320 °C (608 °F).^[2]

In the solid state, SrCl₂ adopts a fluorite structure.^[3][4][5] In the vapour phase the SrCl₂ molecule is non-linear with a Cl-Sr-Cl angle of approximately 130°.^[6] This is an exception to VSEPR theory which would predict a linear structure. Ab initio calculations have been cited to propose that contributions from d orbitals in the shell below the valence shell are responsible.^[7] Another proposal is that polarisation of the electron core of the strontium atom causes a distortion of the core electron density that interacts with the Sr-Cl bonds.^[8]

Strontium chloride is a precursor to other compounds of strontium, such as yellow strontium chromate, strontium carbonate, and strontium sulfate. Exposure of aqueous solutions of strontium chloride to the sodium salt of the desired anion often leads to formation of the solid precipitate:^[9][2]

SrCl₂ + Na₂CrO₄ → SrCrO₄ + 2 NaCl

SrCl₂ + Na₂CO₃ → SrCO₃ + 2 NaCl

SrCl₂ + Na₂SO₄ → SrSO₄ + 2 NaCl

Strontium chloride is often used as a red colouring agent in pyrotechnics. It imparts a much more intense red colour to the flames than most alternatives. It is employed in small quantities in glass-making and metallurgy. The radioactive isotope strontium-89, used for the treatment of bone cancer, is usually administered in the form of strontium chloride. Seawater aquaria require small amounts of strontium chloride, which is consumed during the growth of certain plankton.

SrCl₂ is useful in reducing tooth sensitivity by forming a barrier over microscopic tubules in the dentin containing nerve endings that have become exposed by gum recession. Known in the U.S. as Elecol and Sensodyne, these products are called "strontium chloride toothpastes", although most now use saltpeter (KNO₃) instead which works as an analgesic rather than a barrier.^[10]

Brief strontium chloride exposure induces parthenogenetic activation of oocytes^[11] which is used in developmental biological research.

A commercial company is using a strontium chloride-based artificial solid called AdAmmine as a means to store ammonia at low pressure, mainly for use in NO_x emission reduction on Diesel vehicles. They claim that their patented material can also be made from some other salts, but they have chosen strontium chloride for mass production.^[12] Earlier company research also considered using the stored ammonia as a means to store synthetic ammonia fuel under the trademark HydrAmmine and the press name "hydrogen tablet", however, this aspect has not been commercialized.^[13] Their processes and materials are patented. Their early experiments used magnesium chloride, and is also mentioned in that article.

Strontium chloride is used with citric acid in soil testing as a universal extractant of plant nutrients.^[14]