Uranium(III) iodide

Uranium(III) iodide
Identifiers
CAS Number	13775-18-3 ;
3D model (JSmol)	Interactive image;
ChemSpider	75546;
ECHA InfoCard	100.033.992
EC Number	237-406-4;
PubChem CID	53249297;
CompTox Dashboard (EPA)	DTXSID2065626 ;
	InChI InChI=1S/3HI.U/h3*1H;/q;;;+3/p-3 Key: CDQDFXDBVYMPJX-UHFFFAOYSA-K;
	SMILES [I-].[I-].[I-].[U+3];
Properties
Chemical formula	UI3
Molar mass	618.74232 g/mol
Appearance	black solid
Density	6.78 g/cm3
Melting point	766 °C (1,411 °F; 1,039 K)
Structure
Crystal structure	orthorhombic
Space group	Ccmm, No. 63
Lattice constant	a = 432.8 pm, b = 1401.1 pm, c = 1000.5 pm
Formula units (Z)	4
Hazards
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H300, H330, H373, H411
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Uranium triiodide is an inorganic compound with the chemical formula UI₃. It is a black solid that is soluble in water.

Production

Uranium triiodide can be obtained from the direct reaction of its constituent elements:^[3]

2 U + 3 I₂ → 2 UI₃

When the reaction is conducted in tetrahydrofuran (THF), the product is the blue complex UI₃(THF)₄.^[4]

It crystallizes in the orthorhombic crystal system (plutonium tribromide-type) in the space group Ccmm with the lattice parameters a = 432.8 pm, b = 1401.1 pm, and c = 1000.5 pm and four formula units per unit cell.^[1]

Uranium triiodide can be used as a Lewis acid catalyst for various Diels-Alder reactions carried out under mild conditions.^[5]

^ ^a ^b Levy, J. H.; Taylor, J. C.; Wilson, P. W. (1975-03-01). "The structure of uranium(III) triiodide by neutron diffraction". Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry. 31 (3): 880–882. Bibcode:1975AcCrB..31..880L. doi:10.1107/S0567740875003986. ISSN 0567-7408.
^ Arnold F. Holleman, Nils Wiberg: Lehrbuch der Anorganischen Chemie, 102. Auflage, de Gruyter, Berlin 2007, ISBN 978-3-11-017770-1, S. 1969.
^ Handbuch der präparativen anorganischen Chemie. 2 (3., umgearb. Aufl ed.). Stuttgart: Enke. 1978. ISBN 978-3-432-87813-3.
^ David L. Clark; Alfred P. Sattelberger (1996). "Lewis Base Adducts of Uranium Triiodide and Tris[Bis(Trimethylsilyl)Amido]Uranium". Inorganic Syntheses. Inorganic Synththesis. Vol. 31. pp. 307–315. doi:10.1002/9780470132623.ch55. ISBN 978-0-470-13262-3.
^ Collin, Jacqueline; Maria, Leonor; Santos, Isabel (Oct 2000). "Uranium iodides as catalysts for Diels–Alder reactions". Journal of Molecular Catalysis A: Chemical. 160 (2): 263–267. doi:10.1016/S1381-1169(00)00257-0.