Neodymium(III) iodide 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 ...

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, 593–596 (2000). https://doi.org/10.1007/BF02683920 Neodymium uses the +3 oxidation state in the compound. The anhydrous compound is a green powdery solid at room temperature.

Preparation

Heating neodymium and iodine in an inert atmosphere produces this salt: : 2 Nd + 3 I₂ → 2 NdI₃ It can also be prepared by the reaction of

neodymium(III) oxide Neodymium(III) oxide or neodymium sesquioxide is the chemical compound composed of neodymium and oxygen with the formula Nd2O3. It forms very light grayish-blue hexagonal crystals. The rare-earth mixture didymium, previously believed to be an el ...

and

hydroiodic acid Hydroiodic acid (or hydriodic acid) is an aqueous solution of hydrogen iodide (HI). It is a strong acid, one that is ionized completely in an aqueous solution. It is colorless. Concentrated solutions are usually 48% to 57% HI. Reactions Hyd ...

to make a hydrate: : Nd₂O₃ + 6 HI → 2 NdI₃ + 3 H₂O The anhydrate can then be obtained by heating the nonahydrate with ammonium iodide: : NdI₃ • 9 H₂O + nNH₄I → NdI₃ + nNH₃ + nHI + 9H₂O

Physical properties

Neodymium(III) iodide forms green, water-soluble

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 ...

crystals A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macrosc ...

. It has a melting point of 784°C. It forms a nonahydrate crystal NdI₃.9H₂O – belongs to the

orthorhombic crystal system In crystallography, the orthorhombic crystal system is one of the 7 crystal systems. Orthorhombic lattices result from stretching a cubic lattice along two of its orthogonal pairs by two different factors, resulting in a rectangular prism with a r ...

space group In mathematics, physics and chemistry, a space group is the symmetry group of an object in space, usually in three dimensions. The elements of a space group (its symmetry operations) are the rigid transformations of an object that leave it unchan ...

''Pmmn'', lattice constants a = 1.16604 nm, b = 0.80103 nm, c = 0.89702 nm, Z = 4.

Other compounds

NdI₃ also forms some compounds with N₂H₄, such as NdI₃·3N₂H₄·2H₂O which is a dark green crystal, soluble in

methanol Methanol (also called methyl alcohol and wood spirit, amongst other names) is an organic chemical and the simplest aliphatic alcohol, with the formula C H3 O H (a methyl group linked to a hydroxyl group, often abbreviated as MeOH). It is a ...

and

ethanol Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an Alcohol (chemistry), alcohol with the chemical formula . Its formula can be also written as or (an ethyl ...

and insoluble in water,

benzene Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen atoms, ...

and

toluene Toluene (), also known as toluol (), is a substituted aromatic hydrocarbon. It is a colorless, water-insoluble liquid with the smell associated with paint thinners. It is a mono-substituted benzene derivative, consisting of a methyl group (CH3) at ...

, d_20°C = 3.42 g/cm³. NdI₃ also forms some compounds with

urea Urea, also known as carbamide, is an organic compound with chemical formula . This amide has two amino groups (–) joined by a carbonyl functional group (–C(=O)–). It is thus the simplest amide of carbamic acid. Urea serves an important r ...

, such as NdI₃5CO(NH₂)₂ which is a lavender color crystal. NdI₃ also forms some compounds with

thiourea Thiourea () is an organosulfur compound with the formula and the structure . It is structurally similar to urea (), except that the oxygen atom is replaced by a sulfur atom (as implied by the ''thio-'' prefix); however, the properties of urea ...

, such as NdI₃·2CS(NH₂)2·9H₂O which is a pale pink crystal.Alikberova L.Yu., Albov D.V., Antonenko T.A., Kochetova I.M., Rukk N.S. �
Thiourea complexes of neodymium(III) and gadolinium(III) iodides. synthesis and structure
''Fine Chemical Technologies''. 2010, 5 (3): 30–33. (in Russian).

References

{{Lanthanide halides Neodymium compounds Iodides Lanthanide halides

Preparation

Physical properties

Other compounds

See also

References