Editing Strontium chloride

{{chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 470471352
| Name = 
| ImageFile = Strontium chloride hexahydrate.jpg
| ImageSize = 
| ImageName = Strontium chloride hexahydrate
| IUPACName = Strontium chloride
| SystematicName = 
| OtherNames = Strontium(II) chloride
| Section1 = {{Chembox Identifiers
| Abbreviations = 
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 55440
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = EKE8PS9J6Z
| UNII1_Ref = {{fdacite|correct|FDA}}
| UNII1 = O09USB7Z44
| UNII1_Comment = (hexahydrate)
| ChEBI_Ref = {{ebicite|correct|EBI}}
| ChEBI = 36383
| ChEMBL_Ref = {{ebicite|changed|EBI}}
| ChEMBL = 2219640
| SMILES = [Sr+2].[Cl-].[Cl-]
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/2ClH.Sr/h2*1H;/q;;+2/p-2
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = AHBGXTDRMVNFER-UHFFFAOYSA-L
| InChIKey1 = AHBGXTDRMVNFER-UHFFFAOYSA-L
| CASNo = 10476-85-4
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo1_Ref = {{cascite|correct|CAS}}
| CASNo1 = 10025-70-4
| CASNo1_Comment = (hexahydrate)
| EINECS = 233-971-6
| PubChem = 61520
| InChI = 1S/2ClH.Sr/h2*1H;/q;;+2/p-2
| RTECS = 
  }}
| Section2 = {{Chembox Properties
| Formula = SrCl<sub>2</sub>
| MolarMass = 158.53&nbsp;g/mol (anhydrous)<br/>266.62&nbsp;g/mol (hexahydrate) 
| Appearance = White crystalline solid
| Density = 3.052&nbsp;g/cm<sup>3</sup> (anhydrous, monoclinic form)<br/>2.672&nbsp;g/cm<sup>3</sup> (dihydrate)<br />1.930&nbsp;g/cm<sup>3</sup> (hexahydrate)
| MeltingPtC = 874
| MeltingPt_notes = (anhydrous) <br/> 61&nbsp;°C (hexahydrate) 
| BoilingPtC = 1250
| BoilingPt_notes = (anhydrous) 
| Solubility = ''anhydrous:'' <br/> 53.8&nbsp;g/100&nbsp;mL (20&nbsp;°C) <hr/> ''hexahydrate:'' <br/> 106&nbsp;g/100&nbsp;mL (0&nbsp;°C) <br/> 206&nbsp;g/100&nbsp;mL (40&nbsp;°C)
| SolubleOther = [[ethanol]]: very slightly soluble<br/>[[acetone]]: very slightly soluble <br/> [[ammonia]]: insoluble
| Solvent = 
| LogP = 
| HenryConstant = 
| pKa = 
| pKb = 
| RefractIndex = 1.650 (anhydrous) <br/> 1.594 (dihydrate) <br/> 1.536 (hexahydrate)<ref>Pradyot Patnaik. ''Handbook of Inorganic Chemicals''. McGraw-Hill, 2002, {{ISBN|0-07-049439-8}}</ref>
| MagSus = &minus;63.0·10<sup>−6</sup> cm<sup>3</sup>/mol
  }}
| Section3 = {{Chembox Structure
| CrystalStruct = Deformed [[rutile]] structure
| Coordination = octahedral (six-coordinate)
| MolShape = 
  }}
| Section4 = {{Chembox Thermochemistry
| DeltaHf = 
| DeltaHc = 
| Entropy = 
| HeatCapacity = }}
| Section5 = {{Chembox Pharmacology
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| Section6 = 
| Section7 = {{Chembox Hazards
| ExternalSDS = 
| MainHazards = Irritant
| NFPA-H = 2
| NFPA-F = 0
| NFPA-R = 0
| NFPA-S = 
| HPhrases = 
| PPhrases = 
| GHS_ref  = 
| FlashPt = N/A
| LD50 =
| PEL = 
  }}
| Section8 = {{Chembox Related
| OtherAnions = [[Strontium fluoride]]<br/>[[Strontium bromide]]<br/>[[Strontium iodide]]
| OtherCations = [[Beryllium chloride]]<br/>[[Magnesium chloride]]<br/>[[Calcium chloride]]<br/>[[Barium chloride]]<br/>[[Radium chloride]]
| OtherFunction = 
| OtherFunction_label = 
| OtherCompounds = 
 }}
}}

'''Strontium chloride''' (SrCl<sub>2</sub>) is a [[salt (chemistry)|salt]] of [[strontium]] and [[chloride]]. It is a "typical" salt, forming [[pH|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.{{Citation needed|date=January 2025}} 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]]:
:{{chem2|Sr(OH)2 + 2 HCl → SrCl2  + 2 H2O}}
Crystallization from cold aqueous solution gives the [[water of crystallization|hexahydrate]], SrCl<sub>2</sub>·6H<sub>2</sub>O. Dehydration of this salt occurs in stages, commencing above {{convert|61|C}}. Full dehydration occurs at {{convert|320|C}}.<ref name=Ullmann>{{cite book |doi=10.1002/14356007.a25_321|chapter=Strontium and Strontium Compounds |title=Ullmann's Encyclopedia of Industrial Chemistry |year=2000 |last1=MacMillan |first1=J. Paul |last2=Park |first2=Jai Won |last3=Gerstenberg |first3=Rolf |last4=Wagner |first4=Heinz |last5=Köhler |first5=Karl |last6=Wallbrecht |first6=Peter |isbn=3527306730 }}</ref>

==Structure==
In the solid state, SrCl<sub>2</sub> adopts a [[Fluorite structure|fluorite]] structure.<ref>{{Cite book|last=West, Anthony R.|url=https://www.worldcat.org/oclc/854761803|title=Solid state chemistry and its applications|date=8 January 2014|isbn=978-1-118-67625-7|edition=Second edition, student|location=Chichester, West Sussex, UK|oclc=854761803}}</ref><ref>{{Citation|last=Persson|first=Kristin|title=Materials Data on SrCl<sub>2</sub> by Materials Project|date=2020|url=https://www.osti.gov/servlets/purl/1199327/|others=Materials Project|publisher=LBNL Materials Project; Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)|language=en|doi=10.17188/1199327|access-date=2020-10-10}}</ref><ref>{{Cite web|last1=Mark|first1=H.|last2=Tolksdorf|first2=S.|date=1925|title=Ueber das Beugungsvermoegen der Atome fuer Roentgenstrahlen.|url=http://www.crystallography.net/cod/1010899.html|access-date=2020-10-10|website=www.crystallography.net|language=en}}</ref> In the vapour phase the SrCl<sub>2</sub> molecule is non-linear with a Cl-Sr-Cl angle of approximately 130°.<ref name="Greenwood">{{Greenwood&Earnshaw}}</ref> 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.<ref>[[Ab initio]] model potential study of the equilibrium geometry of alkaline earth dihalides: MX<sub>2</sub> (M=Mg, Ca Sr, Ba; X=F, Cl, Br, I) Seijo L., Barandiarán Z ''J. Chem. Phys.'' 94, 3762 (1991) {{doi|10.1063/1.459748 }}</ref> 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.<ref>"Ion model and equilibrium configuration of the gaseous alkaline-earth dihalides" Guido M. and Gigli G. ''J. Chem. Phys.'' 65, 1397 (1976); {{doi|10.1063/1.433247}}</ref>

== Uses ==
Strontium chloride is a [[Precursor (chemistry)|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:<ref name=hydrometallurgy>{{cite journal |journal= Hydrometallurgy |volume= 84 |issue= 3–4 |year= 2006 |pages= 239–246 |title= Dissolution kinetics of celestite (SrSO<sub>4</sub>) in HCl solution with BaCl<sub>2</sub> |first1= Salih |last1= Aydoğan |first2= Murat |last2= Erdemoğlu |first3= Ali |last3= Aras |first4= Gökhan |last4= Uçar |first5= Alper |last5= Özkan |doi= 10.1016/j.hydromet.2006.06.001 |bibcode= 2006HydMe..84..239A }}</ref><ref name="Ullmann" />

:{{chem2|SrCl2 + Na2CrO4 -> SrCrO4 + 2 NaCl}}
:{{chem2|SrCl2 + Na2CO3 -> SrCO3 + 2 NaCl}}
:{{chem2|SrCl2 + Na2SO4 -> SrSO4 + 2 NaCl}}

Strontium chloride is often used as a red colouring agent in [[pyrotechnics]].{{Citation needed|date=January 2025}} 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 [[Aquarium|aquaria]] require small amounts of strontium chloride, which is consumed during the growth of certain [[plankton]].

===Dental care===
SrCl<sub>2</sub> 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 [[potassium nitrate|saltpeter]] (KNO<sub>3</sub>) instead which works as an analgesic rather than a barrier.<ref>{{cite web |url= http://www.sensodyne.co.uk/how_it_works.htm |publisher= [[Sensodyne]] |title= Sensodyne |access-date= 2008-09-05 |archive-url= https://web.archive.org/web/20080918193411/http://www.sensodyne.co.uk/how_it_works.htm |archive-date= 2008-09-18 |url-status= dead }}</ref>

=== Biological research ===
Brief strontium chloride exposure induces [[Parthenogenesis|parthenogenetic]] activation of [[oocyte]]s<ref>O'Neill GT, Rolfe LR, Kaufman MH. "Developmental potential and chromosome constitution of strontium-induced mouse parthenogenones" (1991) ''Mol. Reprod. Dev.'' 30:214-219</ref> which 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 NO<sub>x</sub> emission reduction on [[diesel engine|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.<ref>{{cite web |publisher=Amminex A/S |title=AdAmmine™ |url=http://amminex.dk/technology/the-solid.aspx |access-date=2013-06-12 |url-status=dead |archive-url=https://web.archive.org/web/20130801102020/http://amminex.dk/technology/the-solid.aspx |archive-date=2013-08-01}}</ref> 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.<ref>{{cite conference |author=Tue Johannesen |title='Solidified' ammonia as an energy storage material for fuel cell applications |publisher=Amminex |conference=2006 Annual NH3 Fuel Conference, October 9 – 10, 2006, Golden, CO |url=https://nh3fuelassociation.org/wp-content/uploads/2012/05/amminex_johannessen.pdf |access-date=2022-11-16 |publication-date=May 2012}} Via [https://nh3fuelassociation.org/ NH3 Fuel Association website].</ref> Their processes and materials are patented. Their early experiments used [[magnesium chloride]], and is also mentioned in that article.

=== Soil testing ===
Strontium chloride is used with citric acid in soil testing as a universal extractant of plant nutrients.<ref>{{cite journal |last1=Simard |first1=R. R. |title=Strontium Chloride-Citric Acid Extraction Evaluated as a Soil-Testing Procedure for Phosphorus |journal=Soil Science Society of America Journal |date=1 March 1991 |volume=55 |issue=2 |page=414 |doi=10.2136/sssaj1991.03615995005500020021x|bibcode=1991SSASJ..55..414S }}</ref>

==References==
{{Reflist}}

==External links==

{{Strontium compounds}}
{{Chlorides}}

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[[Category:Chlorides]]
[[Category:Strontium compounds]]
[[Category:Alkaline earth metal halides]]
[[Category:Fluorite crystal structure]]