Niobium pentaiodide

Niobium(V) iodide is the inorganic compound with the formula Nb₂I₁₀. Its name comes from the compound's empirical formula, NbI₅.[1] It is a diamagnetic, yellow solid that hydrolyses readily. The compound adopts an edge-shared bioctahedral structure, which means that two NbI₅ units are joined by a pair of iodide bridges. There is no bond between the Nb centres.[2] Niobium(V) chloride, niobium(V) bromide, tantalum(V) chloride, tantalum(V) bromide, and tantalum(V) iodide, all share this structural motif.

Niobium pentaiodide

Names
Other names Niobium(V) iodide
Identifiers
CAS Number	13779-92-5
3D model (JSmol)	Interactive image
ChemSpider	75550
ECHA InfoCard	100.034.006
EC Number	237-422-1
PubChem CID	83728
CompTox Dashboard (EPA)	DTXSID1065633
InChI InChI=1S/5HI.Nb/h5*1H;/q;;;;;+5/p-5 Key: FWIYBTVHGYLSAZ-UHFFFAOYSA-I
SMILES [Nb](I)(I)(I)(I)I
Properties
Chemical formula	Nb2I10
Molar mass	1475
Appearance	yellow solid
Density	5.30 g/cm^3
Melting point	543 °C (1,009 °F; 816 K) sublimes
Hazards
GHS pictograms
GHS Signal word	Danger
GHS hazard statements	H314, H318
GHS precautionary statements	P260, P264, P280, P301+330+331, P303+361+353, P304+340, P305+351+338, P310, P321, P363, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Synthesis and structure

Niobium pentaiodide forms from the reaction of niobium with iodine:

2 Nb + 5 I₂ → 2 NbI₅

The method used for the preparation of tantalum(V) iodide using aluminium triiodide fails to produce pure pentaiodide.[3]

References

1. Greenwood, N. N.; & Earnshaw, A. (1997). Chemistry of the Elements (2nd Edn.), Oxford: Butterworth-Heinemann. ISBN 0-7506-3365-4.
2. Krebs, Bernt; Sinram, Diethard "Darstellung, Struktur und Eigenschaften einer neuen Modifikation von NbI₅ (Preparation, structure and properties of a new modification of NbI₅" Zeitschrift fǔr Naturforschung, Teil B: Anorganische Chemie, Organische Chemie 1980, volume 35b, pp. 12-16.
3. G. Braurer (1963). "Niobium(V) Iodide". In G. Brauer (ed.). Handbook of Preparative Inorganic Chemistry, 2nd Ed. 1. NY, NY: Academic Press. p. 1315.