Strontium chloride

Strontium chloride
Strontium chloride hexahydrate
Strontium chloride hexahydrate
Names
IUPAC name
Strontium chloride
Other names
Strontium(II) chloride
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.030.870 Edit this at Wikidata
EC Number
  • 233-971-6
UNII
  • InChI=1S/2ClH.Sr/h2*1H;/q;;+2/p-2 checkY
    Key: AHBGXTDRMVNFER-UHFFFAOYSA-L checkY
  • InChI=1S/2ClH.Sr/h2*1H;/q;;+2/p-2
  • Key: AHBGXTDRMVNFER-UHFFFAOYSA-L
  • [Sr+2].[Cl-].[Cl-]
Properties
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) (anhydrous)
  • 61 °C (142 °F) (hexahydrate, decomposes)
[citation needed]
Boiling point 1,250 °C (2,280 °F; 1,520 K) (anhydrous)
  • anhydrous:
  • 53.8 g/100mL (20 °C (68 °F))
  • hexahydrate:
  • 106 g/100mL (0 °C (32 °F))
  • 206 g/100mL (40 °C (104 °F))
Solubility in ethanol very slight
Solubility in acetone very slight
Band gap 5.23 eV
−63.0×10−6 cm3/mol
  • 1.650 (anhydrous)
  • 1.594 (dihydrate)
  • 1.536 (hexahydrate)
Structure
Fluorite structure
Fm3m
m3m
a = 7.00 Å, b = 7.00 Å, c = 7.00 Å
α = 90°, β = 90°, γ = 90°
342.93 Å3
4
  • Body-centered cubic at Sr2+ to 8 equivalent Cl−
  • Tetrahedral at Cl− to 4 equivalent Sr2+
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
 Irritant
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
2
0
0
Related compounds
Other anions
Other cations
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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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. Its properties are intermediate between those for barium chloride, which is more toxic, and calcium chloride.

Preparation

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).

Structure

In the solid state, SrCl2 adopts a fluorite structure. In the vapour phase the SrCl2 molecule is non-linear with a Cl−Sr−Cl angle of approximately 130°. 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. 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.

Uses

Strontium chloride is a precursor to other compounds of strontium, such as yellow strontium chromate (SrCrO4, strontium carbonate (SrCO3), and strontium sulfate (SrSO4). Exposure of aqueous solutions of strontium chloride to the sodium salt of the desired anion often leads to formation of the solid precipitate:

SrCl2 + Na2CrO4 → SrCrO4 + 2 NaCl
SrCl2 + Na2CO3 → SrCO3 + 2 NaCl
SrCl2 + Na2SO4 → SrSO4 + 2 NaCl

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.[citation needed]

Seawater aquariums require small amounts of strontium chloride, which is consumed during the growth of certain plankton.[citation needed]

Dental care

SrCl2 is marketed as being useful for 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 strontium acetate (Sr(CH3COO)2) or potassium nitrate (KNO3) instead which works as an analgesic rather than a barrier. A literature review of studies which met criteria found that neither is very effective at reducing dentine hypersensitivity.

Biological research

Brief strontium chloride exposure induces parthenogenetic activation of oocytes. This property is used in developmental biological research.

Ammonia storage

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 NOx emission reduction in vehicles with diesel engines. They claim that their patented material can also be made from some other salts, but they have chosen strontium chloride for mass production. 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. Their processes and materials are patented. Their early experiments used magnesium chloride (MgCl2).

Soil testing

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

References

  1. 1 2 3 Persson, Kristin (2020), Materials Data on SrCl2 by Materials Project, Materials Project, LBNL Materials Project; Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States), doi:10.17188/1199327, retrieved 2020-10-10
  2. ↑ Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0-07-049439-8
  3. ↑ "Strontium - ISALTIS". 2019-05-14. Retrieved 2026-04-29.
  4. 1 2 MacMillan, J. Paul; Park, Jai Won; Gerstenberg, Rolf; Wagner, Heinz; Köhler, Karl; Wallbrecht, Peter (2000). "Strontium and Strontium Compounds". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a25_321. ISBN 978-3-527-30673-2.
  5. ↑ Mark, H.; Tolksdorf, S. (1925). "Ueber das Beugungsvermoegen der Atome fuer Roentgenstrahlen". www.crystallography.net. Retrieved 2020-10-10.
  6. ↑ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. doi:10.1016/C2009-0-30414-6. ISBN 978-0-08-037941-8.
  7. ↑ Seijo, Luis; Barandiarán, Zoila; Huzinaga, Sigeru (1 March 1991). "Ab initio model potential study of the equilibrium geometry of alkaline earth dihalides: MX2 (M=Mg, Ca, Sr, Ba; X=F, Cl, Br, I)". The Journal of Chemical Physics. 94 (5): 3762–3773. doi:10.1063/1.459748.
  8. ↑ Guido, M.; Gigli, G. (15 August 1976). "Ion model and equilibrium configuration of the gaseous alkaline-earth dihalides". The Journal of Chemical Physics. 65 (4): 1397–1402. doi:10.1063/1.433247.
  9. ↑ Aydoğan, Salih; Erdemoğlu, Murat; Aras, Ali; Uçar, Gökhan; Özkan, Alper (2006). "Dissolution kinetics of celestite (SrSO4) in HCl solution with BaCl2". Hydrometallurgy. 84 (3–4): 239–246. Bibcode:2006HydMe..84..239A. doi:10.1016/j.hydromet.2006.06.001.
  10. ↑ "Sensodyne". www.sensodyne.co.uk. Sensodyne. Archived from the original on 2008-09-18. Retrieved 2008-09-05.
  11. ↑ Karim, B. F. A.; Gillam, D. G. (2013). "The Efficacy of Strontium and Potassium Toothpastes in Treating Dentine Hypersensitivity: A Systematic Review". International Journal of Dentistry. 2013: 1–13. doi:10.1155/2013/573258. PMC 3638644. PMID 23653647.
  12. ↑ O'Neill, G. T.; Rolfe, L. R.; Kaufman, M. H. (November 1991). "Developmental potential and chromosome constitution of strontium‐induced mouse parthenogenones". Molecular Reproduction and Development. 30 (3): 214–219. doi:10.1002/mrd.1080300308. PMID 1793599.
  13. ↑ "AdAmmine™". Amminex A/S. Archived from the original on 2013-08-01. Retrieved 2013-06-12.
  14. ↑ Tue Johannesen (May 2012). 'Solidified' ammonia as an energy storage material for fuel cell applications (PDF). 2006 Annual NH3 Fuel Conference, October 9 – 10, 2006, Golden, CO. nh3fuelassociation.org. Amminex. Retrieved 2022-11-16 – via NH3 Fuel Association.
  15. ↑ Simard, R. R. (1 March 1991). "Strontium Chloride-Citric Acid Extraction Evaluated as a Soil-Testing Procedure for Phosphorus". Soil Science Society of America Journal. 55 (2): 414. Bibcode:1991SSASJ..55..414S. doi:10.2136/sssaj1991.03615995005500020021x.