Neodymium(II) iodide

Neodymium(II) iodide can be made by heating molten neodymium(III) iodide with neodymium metal at 800 and 580°C for 12 hours. It can also be obtained by reducing neodymium(III) iodide with neodymium in a vacuum at 800 to 900°C:

:Nd + 2NdI₃ → 3NdI₂

The reaction of neodymium with mercury(II) iodide is also possible because neodymium is more reactive than mercury:

:Nd + HgI₂ → NdI₂ + Hg

Direct preparation from iodine and neodymium is also possible:{{Cite book | author = Karl A. Jr. Gschneidner, Jean-Claude Bunzli, Vitalij K. Pecharsky | title = Handbook on the Physics and Chemistry of Rare Earths | publisher = Elsevier | isbn = 978-008093257-6 | year = 2009 | url = https://books.google.com/books?id=CV-YrFC8_YIC&pg=PA247 | page = 247 }}

:Nd + I₂ → NdI₂

The compound was first synthesized by John D. Corbett in 1961.Angelika Jungmann, R. Claessen, R. Zimmermann, G. e. Meng, P. Steiner, S. Hüfner, S. Tratzky, K. Stöwe, H. P. Beck: Photoemission of LaI₂ and CeI₂. In: Zeitschrift für Physik B Condensed Matter. 97, 1995, S. 25–34, {{doi|10.1007/BF01317584}}.

Neodymium(II) iodide is a violet solid. The compound is extremely hygroscopic, and can only be stored and handled under carefully dried inert gas or under a high vacuum.{{ cite journal | title = Rare Earth Starting Materials and Methodologies for Synthetic Chemistry | first1 = Fabrizio | last1 = Ortu | journal = Chem. Rev. | year = 2022 | volume = 122 | issue = 6 | pages = 6040–6116 | doi = 10.1021/acs.chemrev.1c00842 | pmid = 35099940 | pmc = 9007467 | doi-access = free }} In air it converts into hydrates by absorbing moisture, but these are unstable and more or less rapidly transform into oxide iodides with the evolution of hydrogen:

:2NdI₂ + 2H₂O → 2NdOI + H₂↑ + 2HI

Neodymium(II) iodide is not stoichiometric, and has a formula of closer to NdI_1.95. It melts at 562°C.{{cite journal |last1=Druding |first1=Leonard F. |last2=Corbett |first2=John D. |title=Lower Oxidation States of the Lanthanides. Neodymium(II) Chloride and Iodide 1 |journal=Journal of the American Chemical Society |date=June 1961 |volume=83 |issue=11 |pages=2462–2467 |doi=10.1021/ja01472a010|bibcode=1961JAChS..83.2462D }} It has a strontium(II) bromide-type crystal structure. Under pressure, this transforms into the molybdenum disilicide structure typically seen in intermetallic compound, which is already present under normal conditions in other rare earth diiodides (e.g. praseodymium(II) iodide and lanthanum(II) iodide).{{Cite book | author = Ralf Alsfasser, Erwin Riedel | title = Moderne Anorganische Chemie | publisher = Walter de Gruyter | isbn = 978-311019060-1 | year = 2007 | url = https://books.google.com/books?id=HwY4be5bH_sC&pg=PA188 | page = 188 }} It forms complexes with tetrahydrofuran and other organic compounds.Mikhail N. Bochkarev, Igor L. Fedushkin, Sebastian Dechert, Anatolii A. Fagin, Herbert Schumann: [NdI₂(thf)₅], der erste kristallographisch charakterisierte Neodym(II)-Komplex. In: Angewandte Chemie. 113, 2001, S. 3268–3270, {{doi|10.1002/1521-3757(20010903)113:17<3268::AID-ANGE3268>3.0.CO;2-K}}.G. V. Khoroshen kov, A. A. Fagin, M. N. Bochkarev, S. Dechert, H. Schumann: Reactions of neodymium(II), dysprosium(II), and thulium(II) diiodides with cyclopentadiene In: Russian Chemical Bulletin. 52, S. 1715–1719, {{doi|10.1023/A:1026132017155}}.

Neodymium(II) iodide is an electrical insulator.{{cite journal |last1=Sallach |first1=Robert A. |last2=Corbett |first2=John D. |title=Magnetic Susceptibilities of Neodymium (II) Chloride and Iodide |journal=Inorganic Chemistry |date=July 1964 |volume=3 |issue=7 |pages=993–995 |doi=10.1021/ic50017a015}}

Neodymium(II) iodide reacts with organohalides by extracting the halogen, resulting in dimers, oligomers or reactions with the solvent.{{cite journal |last1=Fagin |first1=Anatolii A. |last2=Balashova |first2=Tatyana V. |last3=Kusyaev |first3=Dmitrii M. |last4=Kulikova |first4=Tatyana I. |last5=Glukhova |first5=Tatyana A. |last6=Makarenko |first6=Natalya P. |last7=Kurskii |first7=Yurii A. |last8=Evans |first8=William J. |last9=Bochkarev |first9=Mikhail N. |display-authors=3|title=Reactions of neodymium(II) iodide with organohalides |journal=Polyhedron |date=March 2006 |volume=25 |issue=5 |pages=1105–1110 |doi=10.1016/j.poly.2005.08.050}}

Solvates are known with tetrahydrofuran and dimethoxyethane: NdI₂(THF)₂ and NdI₂(DME)₂.{{cite journal |last1=Bochkarev |first1=Mikhail N. |last2=Fagin |first2=Anatolii A. |title=A New Route to Neodymium(II) and Dysprosium(II) Iodides |journal=Chemistry - A European Journal |date=24 September 1999 |volume=5 |issue=10 |pages=2990–2992 |doi=10.1002/(SICI)1521-3765(19991001)5:10<2990::AID-CHEM2990>3.0.CO;2-U}}

Neodymium(II) iodide reduces hot nitrogen to form an iodide nitride: (NdI₂)₃N which with THF also gives (NdI)₃N₂.{{cite journal |last1=Fagin |first1=A. A. |last2=Salmova |first2=S. V. |last3=Bochkarev |first3=M. N. |title=Reduction of nitrogen with neodymium(II) and dysprosium(II) diiodides and selected properties of the resulting nitrides |journal=Russian Chemical Bulletin |date=January 2009 |volume=58 |issue=1 |pages=230–233 |doi=10.1007/s11172-009-0034-2|s2cid=98798042 }}

It reacts with cyclopentadiene in THF to give CpNdI₂(THF)₃.{{cite journal |last1=Khoroshen'kov |first1=G. V. |last2=Fag |first2=A. A. |last3=Bochkarev |first3=M. N. |last4=Dechert |first4=S. |last5=Schumann |first5=H. |title=Reactions of neodymium(ii), dysprosium(ii), and thulium(ii) diiodides with cyclopentadiene. Molecular structures of complexes CpTmI2(THF)3 and [NdI2(THF)5]+[NdI4(THF)2]– |journal=Russian Chemical Bulletin |date=1 August 2003 |volume=52 |issue=8 |pages=1715–1719 |doi=10.1023/A:1026132017155|s2cid=91646257 }}

Neodymium(II) iodide can be used as a reducing agent or catalyst{{Cite book | author = Fundamental Chemistry | title = Neodymium Based Ziegler Catalysts | publisher = Springer | isbn = 354034809-3 | year = 2006 | url = https://books.google.com/books?id=xX9mYOp2HFYC&pg=PA13| page = 13 }} in organic chemistry.{{Cite book | author = | title = Handbook on the Physics and Chemistry of Rare Earths | publisher = Elsevier | isbn = 978-008093257-6 | year = 2009 | url = https://books.google.com/books?id=CV-YrFC8_YIC&pg=PA261 | page = 261 }}

• Neodymium(III) iodide
• Lanthanide

{{reflist}}

{{neodymium compounds}}

{{Iodine compounds}}

{{Iodides}}

{{Lanthanide halides}}

Category:Neodymium(II) compounds

Category:Iodides

Category:Lanthanide halides