{{Chembox | ImageFile = | ImageSize = | PIN = Calcium polonide |Section1 = {{Chembox Identifiers | CASNo = 51681-45-9 | CASNo_Ref = {{cascite|correct|CAS}} | ChemSpiderID = 129549187 | PubChem = <!--165360201 charge error--> | SMILES = [Ca+2].[Po-2] | StdInChI=1S/Ca.Po/q+2;-2 | StdInChIKey=NWHIVWOERKOURT-UHFFFAOYSA-N }} |Section2 = {{Chembox Properties | Ca=1|Po=1 | Density=6.0 g/cm<sup>3</sup> }} |Section3 = {{Chembox Structure | Structure_ref = <ref name=Witteman1960 /> | CrystalStruct = Rock Salt (cubic) | SpaceGroup = Fm{{overline|3}}m (No. 225) | LattConst_a = 0.6514 nm | LattConst_Comment = | UnitCellVolume = | UnitCellFormulas = | Coordination = }} }}
'''Calcium polonide''' is an intermetallic compound with the chemical formula {{chem2|CaPo|auto=1}}. It is made up of calcium and polonium. Rather than being found in nature, the compound is entirely synthetic, and difficult to study, due to polonium's high vapor pressure, radioactivity, and easy oxidation in air.
==Structure== At atmospheric pressure, it crystalizes in the cubic rock salt crystal structure.<ref name=Witteman1960>{{cite journal | last1=Witteman | first1=W. G. | last2=Giorgi | first2=A. L. | last3=Vier | first3=D. T. | title=The Preparation and Identification of Some Intermetallic Compounds of Polonium | journal=The Journal of Physical Chemistry | publisher=American Chemical Society (ACS) | volume=64 | issue=4 | year=1960 | issn=0022-3654 | doi=10.1021/j100833a014 | pages=434–440}}</ref> At a high pressure of around 16.7 GPa, the structure is predicted to transform to the caesium chloride-type crystal structure.<ref>{{cite journal | last1=Shi | first1=Liwei | last2=Wu | first2=Ling | last3=Duan | first3=Yifeng | last4=Hao | first4=Lanzhong | last5=Hu | first5=Jing | last6=Yang | first6=Xianqing | last7=Tang | first7=Gang | title=Band structure, phase transition, phonon and elastic instabilities in calcium polonide under pressure: A first-principles study | journal=Solid State Communications | publisher=Elsevier BV | volume=152 | issue=22 | year=2012 | issn=0038-1098 | doi=10.1016/j.ssc.2012.08.028 | pages=2058–2062| bibcode=2012SSCom.152.2058S}}</ref>
==Electronic properties== Based on theoretical calculations, calcium polonide is predicted to be a semiconductor.<ref>{{cite journal | last1=Bhardwaj | first1=Purvee | last2=Singh | first2=Sadhna | title=Phase transition and bulk properties of some polonide compounds: a comparative study | journal=Phase Transitions | publisher=Informa UK Limited | volume=88 | issue=9 | date=2015-06-09 | issn=0141-1594 | doi=10.1080/01411594.2015.1020312 | pages=859–876| bibcode=2015PhaTr..88..859B | s2cid=93331676}}</ref>
==See also== * Magnesium polonide * Potassium polonide
==References== {{reflist}} {{Polonium compounds}} {{Calcium compounds}}
Category:Polonides Category:Calcium compounds Category:Rock salt crystal structure
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