Neodymium(III) iodide explained

Neodymium(III) iodide is an inorganic salt of iodine and neodymium with the formula NdI₃.^[1] 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 NdI₃It can also be prepared by the reaction of neodymium(III) oxide and hydroiodic acid to make a hydrate:^[2]

Nd₂O₃ + 6 HI → 2 NdI₃ + 3 H₂OThe 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 crystals. It has a melting point of 784°C. It forms a nonahydrate crystal NdI₃.9H₂O – belongs to the orthorhombic crystal system, space group Pmmn, lattice constants a = 1.16604 nm, b = 0.80103 nm, c = 0.89702 nm, Z = 4.^[3]

Other compounds

NdI₃ also forms some compounds with N₂H₄, such as NdI₃·3N₂H₄·2H₂O which is a dark green crystal, soluble in methanol and ethanol and insoluble in water, benzene and toluene, d_20°C = 3.42 g/cm³.^[4]

NdI₃ also forms some compounds with urea, such as NdI₃ 5CO(NH₂)₂ which is a lavender color crystal.^[5]

NdI₃ also forms some compounds with thiourea, such as NdI₃·2CS(NH₂)2·9H₂O which is a pale pink crystal.^[6]

See also

• Neodymium(II) iodide
• Neodymium
• Iodine
• Lanthanide

Notes and References

1. 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
2. Kutscher . J. . Schneider . A. . 1971-09-01 . Notiz zur Präparation von wasserfreien Lanthaniden-Haloge-niden, Insbesondere von Jodiden . Inorganic and Nuclear Chemistry Letters . de . 7 . 9 . 815–819 . 10.1016/0020-1650(71)80253-2 . 0020-1650.
3. T. Timofte, A. Babai, G. Meyer and A.-V. Mudring . Neodymium triiodide nonahydrate . Acta Crystallographica Section E . 2005 . E61 . 5 . i87–i88 . 10.1107/S160053680501216X .
4. https://books.google.com/books?id=OJs4AAAAIAAJ Uchenye zapiski: Serii︠a︡ khimicheskikh nauk
5. https://books.google.com/books?id=8VlHAQAAIAAJ Russian Journal of Inorganic Chemistry, Episode 18, Part 2
6. 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).