Neodymium(III) iodide is an

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

salt of

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

and

neodymium Neodymium is a chemical element; it has Symbol (chemistry), 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 element, rare-earth metals. It is a hard (physics), hard, sli ...

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 e ...

and

hydroiodic acid Hydroiodic acid (or hydriodic acid) is a colorless liquid. It is an aqueous solution of hydrogen iodide with the chemical formula . It is a strong acid, in which hydrogen iodide is ionized completely in an aqueous solution. Concentrated aqueous ...

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 (chemistry), absorption or adsorption from the surrounding Natural environment, environment, which is usually at normal or room temperature. If water mol ...

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 ...

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

''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 compound and the simplest aliphatic Alcohol (chemistry), alcohol, with the chemical formula (a methyl group linked to a hydroxyl group, often ab ...

and

ethanol Ethanol (also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound with the chemical formula . It is an Alcohol (chemistry), alcohol, with its formula also written as , or EtOH, where Et is the ps ...

and insoluble in water,

benzene Benzene is an Organic compound, organic chemical compound with the Chemical formula#Molecular formula, molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar hexagonal Ring (chemistry), ring with one hyd ...

and

toluene Toluene (), also known as toluol (), is a substituted aromatic hydrocarbon with the chemical formula , often abbreviated as , where Ph stands for the phenyl group. It is a colorless, water Water is an inorganic compound with the c ...

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

urea Urea, also called carbamide (because it is a diamide of carbonic acid), is an organic compound with chemical formula . This amide has two Amine, amino groups (–) joined by a carbonyl functional group (–C(=O)–). It is thus the simplest am ...

, 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 (), with the oxygen atom replaced by sulfur atom (as implied by the '' thio-'' prefix). The properties of urea and thiourea differ s ...

, 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(III) compounds Iodides Lanthanide halides

Preparation

Physical properties

Other compounds

See also

References