Thorium (II) iodide

Crystal structure
	__ Th 2+ __ I -
Crystal system	hexagonal
Space group	P 6 3 / mmc (No. 194)
Lattice parameters	a = 396 pm ; c = 3176 pm
General
Surname	Thorium (II) iodide
other names	Thorium diiodide
Ratio formula	ThI 2
Brief description	black solid
External identifiers / databases
Wikidata	Q17265575
properties
Molar mass	612.75 g mol −1
Physical state	firmly
density	7.21 g cm −3
Melting point	850 ° C (decomposition)
Hazard and safety information
	; Radioactive
GHS hazard labeling ; no classification available
GHS hazard labeling ; no classification available
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Thorium (II) iodide is a chemical compound of thorium from the group of iodides .

presentation

Thorium (II) iodide can be obtained by reacting thorium (IV) iodide with thorium at 600 ° C for several days . If the resulting compound is quenched at this temperature, α-thorium (II) iodide is obtained. However, if the reaction is carried out at 800 ° C. and then quenched, the β form is obtained.

{\ displaystyle \ mathrm {Th + ThI_ {4} \ longrightarrow 2 \ ThI_ {2}}}

Representation by reaction from the elements is also possible

{\ displaystyle \ mathrm {Th + I_ {2} \ longrightarrow ThI_ {2}}}

or the thermal decomposition of thorium (III) iodide at temperatures above 550 ° C.

{\ displaystyle \ mathrm {2 \ ThI_ {3} \ longrightarrow ThI_ {4} + ThI_ {2}}}

properties

Thorium (II) iodide comes in two modifications. At 600–700 ° C the α- converts to the β-form. The α-form is a black, mostly poorly crystallized mass with a weak bronze shimmer. Smaller particles are somewhat transparent with a slight dichroism from brownish to purple. The β-form is a metallic-gold-shiny solid, in which well-crystallized parts are present in the form of shiny, irregular six-sided platelets that are relatively soft and provide a shiny metallic line. Both forms have a hexagonal crystal structure (α-form: a = 396 pm, c = 3176 pm, β-form: a = 912 pm, b = 374 pm), whereby the α-form has the space group P 6 ₃ / mmc (space groups No. 194) . The α-form crystallizes in a layer structure in which two crystallographically different Th ions exist. In one type of layer the Th ions are octahedral coordinated, in the adjacent layers the coordination polyhedra are trigonal prisms . Template: room group / 194

Individual evidence

↑ ^a ^b ^c ^d ^e ^f Georg Brauer (Ed.), With the collaboration of Marianne Baudler u. a .: Handbook of Preparative Inorganic Chemistry. 3rd, revised edition. Volume I, Ferdinand Enke, Stuttgart 1975, ISBN 3-432-02328-6 , p. 1142.
^ ^A ^b Lloyd J. Guggenberger, RA Jacobson: Crystal structure of thorium diiodide. In: Inorganic Chemistry. 7, 1968, pp. 2257-2260, doi : 10.1021 / ic50069a017 .
^ Lester R. Morss, Norman M. Edelstein, J. Fuger (Eds.): The Chemistry of the Actinide and Transactinide Elements (Set Vol. 1-6) . Springer, 2010, ISBN 978-94-007-0211-0 , pp. 84 ( limited preview in Google Book search).
↑ The hazards emanating from radioactivity do not belong to the properties to be classified according to the GHS labeling. With regard to other hazards, this substance has either not yet been classified or a reliable and citable source has not yet been found.

[brauer-1] ↑ ^a ^b ^c ^d ^e ^f Georg Brauer (Ed.), With the collaboration of Marianne Baudler u. a .: Handbook of Preparative Inorganic Chemistry. 3rd, revised edition. Volume I, Ferdinand Enke, Stuttgart 1975, ISBN 3-432-02328-6 , p. 1142.

[DOI10.1021/ic50069a017-2] A ^b Lloyd J. Guggenberger, RA Jacobson: Crystal structure of thorium diiodide. In: Inorganic Chemistry. 7, 1968, pp. 2257-2260, doi : 10.1021 / ic50069a017 .

[Lester_R._Morss,_Norman_M._Edelstein,_J._Fuger-3] Lester R. Morss, Norman M. Edelstein, J. Fuger (Eds.): The Chemistry of the Actinide and Transactinide Elements (Set Vol. 1-6) . Springer, 2010, ISBN 978-94-007-0211-0 , pp. 84 ( limited preview in Google Book search).

[NV-4] The hazards emanating from radioactivity do not belong to the properties to be classified according to the GHS labeling. With regard to other hazards, this substance has either not yet been classified or a reliable and citable source has not yet been found.