Europium(II) iodide
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| Name = Europium(II) iodide
| IUPACName = Europium(II) iodide
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| Section1 = {{Chembox Identifiers
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| CASNo = 22015-35-6
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| ChemSpiderID = 80445
| EC_number = 244-721-0
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| PubChem = 519914
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| SMILES = I[Eu]I
| StdInChI=1S/Eu.2HI/h;2*1H/q+2;;/p-2
| StdInChIKey = DPYXWFUVSMSNNV-UHFFFAOYSA-L
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| Section2 = {{Chembox Properties
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| Appearance = Tea yellow powder
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| BoilingPtC = 1120
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| Formula = {{chem|Eu|I|2}}
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| MolarMass = 405.77 g/mol
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| MeltingPtC = 510
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| Solubility = Soluble in THF
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Europium(II) iodide is the iodide salt of divalent europium cation.
Preparation
Europium(II) iodide can be prepared in a handful of ways, including:
Reduction of europium(III) iodide with hydrogen gas at 350 °C:{{cite book |last=Brauer|first=Georg|author-link=Georg Brauer|date=1975|title=Handbook of Preparative Inorganic Chemistry|url= |location= |publisher= |page= |isbn=3-432-02328-6}}
:{{Chem2|2 EuI3 + H2 -> 2 EuI2 + 2 HI}}
Thermal decomposition of europium(III) iodide at 200 °C:
:{{Chem2|2 EuI3 -> 2 EuI2 + 2 I2}}
Reaction of europium with mercury(II) iodide:
:{{Chem2|Eu + HgI2 -> Eu I2 + Hg}}
Reaction of europium with ammonium iodide:
:{{Chem2|Eu + 2 NH4I -> EuI2 + 2 NH3 + H2}}
Structure
Europium(II) iodide has several polymorphs.{{ cite book | first1 = A. F. | last1 = Wells | title = Structural Inorganic Chemistry | edition = 5th | year = 1984 | publisher = Oxford University Press | isbn = 978-0-19-965763-6 | pages = 415–416 }} It adopts a monoclinic crystal structure in space group P 21/c (no. 14).{{ cite journal | first1 = H. | last1 = Bärnighausen | authorlink1 = Hartmut Bärnighausen | first2 = H. | last2 = Beck | first3 = H. W. | last3 = Grueninger | first4 = E. T. | last4 = Rietschel | first5 = N. | last5 = Schultz | title = Neue AB2-strukturtypen mit siebenfach koordiniertem kation | journal = Z. Kristallogr. | year = 1969 | volume = 128 | page = 430 }}{{ cite journal | first1 = H. | last1 = Bärnighausen | first2 = N. | last2 = Schulz | title = Die Kristallstruktur der monoklinen Form von Europium(II)-jodid EuJ2 | journal = Acta Crystallogr. B | year = 1969 | volume = 25 | pages = 1104–1110 | doi = 10.1107/S0567740869003591 }}
It also adopts an orthorhombic polymorph in space group Pbca (no. 61). This form is isostructural with strontium iodide.{{ cite journal | first1 = H. | last1 = Bärnighausen | first2 = H. P. | last2 = Beck | first3 = H. W. | last3 = Grueninger | title = Search Results - Access Structures | journal = Rare Earths Mod. Sci. Technol. | year = 1971 | volume = 9 | pages= 74– | url = https://www.ccdc.cam.ac.uk/structures/Search?Ccdcid=1621024&DatabaseToSearch=Published }}
A third polymorph of europium(II) iodide is formed if it is prepared from europium and ammonium iodide at low temperatures (200 K) in liquid ammonia. This low-temperature phase is orthorhombic and in space group Pnma (no. 62). This is the same structure as modification IV of strontium iodide.{{ cite journal | first1 = M. | last1 = Krings | first2 = M. | last2 = Wessel | first3 = R. | last3 = Dronskowski | title = EuI2, a low-temperature europium(II) iodide phase | journal = Acta Crystallogr. C | year = 2009 | volume = 65 | pages = i66–i68 | doi = 10.1107/S0108270109038542 }}
References
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{{Europium compounds}}
{{Iodides}}
{{Lanthanide halides}}
Category:Europium(II) compounds
{{Inorganic-compound-stub}}