Tantalum(V) iodide

Tantalum(V) iodide
Names
	Other names Tantalum pentaiodide
Identifiers
CAS Number	14693-81-3 TaI5 ; 26814-38-0 Ta2I10;
3D model (JSmol)	Interactive image;
ChemSpider	76319;
EC Number	238-742-4;
PubChem CID	84598;
	InChI InChI=1S/5HI.Ta/h5*1H;/q;;;;;+5/p-5 Key: MISXNQITXACHNJ-UHFFFAOYSA-I;
	SMILES [I-].[I-].[I-].[I-].[I-].[Ta+5];
Properties
Chemical formula	Ta2I10
Molar mass	1631
Appearance	black solid
Density	5.8 g/cm3
Melting point	382 °C (720 °F; 655 K) sublimes
Hazards
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H314, H331
Precautionary statements	P260, P261, P264, P271, P280, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P311, P321, P363, P403+P233, P405, P501
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Tantalum(V) iodide is the inorganic compound with the formula Ta₂I₁₀. Its name comes from the compound's empirical formula, TaI₅.^[2] It is a diamagnetic, black solid that hydrolyses readily. The compound adopts an edge-shared bioctahedral structure, which means that two TaI₅ units are joined by a pair of iodide bridges. There is no bond between the Ta centres.^[3] Niobium(V) chloride, niobium(V) bromide, niobium(V) iodide, tantalum(V) chloride, and tantalum(V) bromide all share this structural motif.

Synthesis and structure

Tantalum pentaiodide forms from the reaction of tantalum pentoxide with aluminium triiodide:^[4]

3 Ta₂O₅ + 10 AlI₃ → 6 TaI₅ + 5 Al₂O₃

^ McCarley, R. E.; Boatman, J.C. (1965). "The Equilibrium Phase Diagrams for the Tantalum-Tantalum Bromide and Tantalum-Tantalum Iodide Systems". Inorganic Chemistry. 4 (10): 1486–1491. doi:10.1021/ic50032a029. S2CID 67778953.
^ Greenwood, N. N.; & Earnshaw, A. (1997). Chemistry of the Elements (2nd Edn.), Oxford: Butterworth-Heinemann. ISBN 0-7506-3365-4.
^ Müller, U. (1979). "Die Kristallstruktur von Tantalpentajodid und ihre Fehlordnung". Acta Crystallographica Section B: Structural Crystallography and Crystal Chemistry. 35 (11): 2502–2509. Bibcode:1979AcCrB..35.2502M. doi:10.1107/S0567740879009778.
^ G. Braurer (1963). "Niobium(V) and Tantalum(V) Bromides". In G. Brauer (ed.). Handbook of Preparative Inorganic Chemistry, 2nd Ed. Vol. 1. NY, NY: Academic Press. p. 1311.