Neodymium(II) iodide or neodymium diiodide is an

inorganic In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemist ...

salt of

iodine Iodine is a chemical element with the symbol I and atomic number 53. The heaviest of the stable halogens, it exists as a semi-lustrous, non-metallic solid at standard conditions that melts to form a deep violet liquid at , and boils to a vi ...

and

neodymium Neodymium is a chemical element with the symbol Nd and atomic number 60. It is the fourth member of the lanthanide series and is considered to be one of the rare-earth metals. It is a hard, slightly malleable, silvery metal that quickly tarnishes i ...

the formula NdI₂. Neodymium uses the +2 oxidation state in the compound. Neodymium(II) iodide is a violet solid. The compound is not

stoichiometric Stoichiometry refers to the relationship between the quantities of reactants and products before, during, and following chemical reactions. Stoichiometry is founded on the law of conservation of mass where the total mass of the reactants equal ...

. It melts at 562°C.

Preparation

Neodymium(II) iodide can be made by heating molten

neodymium(III) iodide Neodymium(III) iodide is an inorganic salt of iodine and neodymium with the formula NdI3.Ezhov, Y.S., Komarov, S.A. & Sevast’yanov, V.G. Refinement of molecular constants of neodymium triiodide by electron diffraction. ''J Struct Chem ''41, 593� ...

with

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 Mercury(II) iodide is a chemical compound with the molecular formula Hg I2. It is typically produced synthetically but can also be found in nature as the extremely rare mineral coccinite. Unlike the related mercury(II) chloride it is hardly solu ...

is also possible because neodymium is more reactive than mercury: :Nd + HgI₂ → NdI₂ + Hg Direct preparation from iodine and neodymium is also possible: :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, .

Properties

Neodymium(II) iodide is a violet solid. The compound is extremely

hygroscopic Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption or adsorption from the surrounding environment, which is usually at normal or room temperature. If water molecules become suspended among the substance ...

, and can only be stored and handled under carefully dried inert gas or under a high vacuum. In air it converts into

hydrate In chemistry, a hydrate is a substance that contains water or its constituent elements. The chemical state of the water varies widely between different classes of hydrates, some of which were so labeled before their chemical structure was understo ...

s by absorbing moisture, but these are unstable and more or less rapidly transform into oxide iodides with the evolution of

hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, an ...

: :2NdI₂ + 2H₂O → 2NdOI + H₂↑ + 2HI Neodymium(II) iodide is not

, and has a formula of closer to NdI_1.95. It melts at 562°C. 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 Lanthanum diiodide is an iodide of lanthanum, with the chemical formula of LaI2. It is an electride, actually having a chemical formula of La3+ I−)2e− Preparation Lanthanum diiodide can be obtained from the reduction of lanthanum(III) ...

). It forms complexes with

tetrahydrofuran Tetrahydrofuran (THF), or oxolane, is an organic compound with the formula (CH2)4O. The compound is classified as heterocyclic compound, specifically a cyclic ether. It is a colorless, water-miscible organic liquid with low viscosity. It is ma ...

and other

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The ...

s.Mikhail N. Bochkarev, Igor L. Fedushkin, Sebastian Dechert, Anatolii A. Fagin, Herbert Schumann: '' dI₂(thf)₅ der erste kristallographisch charakterisierte Neodym(II)-Komplex.'' In: ''Angewandte Chemie.'' 113, 2001, S. 3268–3270, .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, .Anatolii A. Fagin, Tatyana V. Balashova, Dmitrii M. Kusyaev, Tatyana I. Kulikova, Tatyana A. Glukhova, Natalya P. Makarenko, Yurii A. Kurskii, William J. Evans, Mikhail N. Bochkarev: ''Reactions of neodymium(II) iodide with organohalides.'' In: ''Polyhedron.'' 25, 2006, S. 1105–1110, . Neodymium(II) iodide is an

electrical insulator An electrical insulator is a material in which electric current does not flow freely. The atoms of the insulator have tightly bound electrons which cannot readily move. Other materials—semiconductors and conductors—conduct electric current ...

Reactions

Neodymium(II) iodide reacts with

organohalide Halocarbon compounds are chemicals in which one or more carbon atoms are linked by covalent bonds with one or more halogen atoms (fluorine, chlorine, bromine or iodine – ) resulting in the formation of organofluorine compounds, organochlorin ...

s by extracting the

halogen The halogens () are a group in the periodic table consisting of five or six chemically related elements: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At), and tennessine (Ts). In the modern IUPAC nomenclature, this group is ...

, resulting in dimers,

oligomer In chemistry and biochemistry, an oligomer () is a molecule that consists of a few repeating units which could be derived, actually or conceptually, from smaller molecules, monomers.Quote: ''Oligomer molecule: A molecule of intermediate relativ ...

s or reactions with the

solvent A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for ...

Solvate Solvation (or dissolution) describes the interaction of a solvent with dissolved molecules. Both ionized and uncharged molecules interact strongly with a solvent, and the strength and nature of this interaction influence many properties of the ...

s are known with

and

dimethoxyethane Dimethoxyethane, also known as glyme, monoglyme, dimethyl glycol, ethylene glycol dimethyl ether, dimethyl cellosolve, and DME, is a colorless, aprotic, and liquid ether that is used as a solvent, especially in batteries. Dimethoxyethane is misci ...

: NdI₂(THF)₂ and NdI₂(DME)₂. Neodymium(II) iodide reduces hot

nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...

to form an iodide nitride: (NdI₂)₃N which with THF also gives (NdI)₃N₂. It reacts with

cyclopentadiene Cyclopentadiene is an organic compound with the chemical formula, formula C5H6.LeRoy H. Scharpen and Victor W. Laurie (1965): "Structure of cyclopentadiene". ''The Journal of Chemical Physics'', volume 43, issue 8, pages 2765-2766. It is often ab ...

in THF to give CpNdI₂(THF)₃.

Applications

Neodymium(II) iodide can be used as a

reducing agent In chemistry, a reducing agent (also known as a reductant, reducer, or electron donor) is a chemical species that "donates" an electron to an (called the , , , or ). Examples of substances that are commonly reducing agents include the Earth meta ...

catalyst Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...

in organic chemistry.

References

{{Lanthanide halides Neodymium compounds Iodides Lanthanide halides

Preparation

Properties

Reactions

Applications

See also

References