Nickel (II) iodide

Crystal structure
	__ Ni 2+ __ I -
General
Surname	Nickel (II) iodide
other names	Nickel diiodide; Nickel iodide;
Ratio formula	NiI 2
Brief description	black, crystalline powder (pure substance); blue-green prismatic crystals (hexahydrate);
External identifiers / databases
EC number	236-666-6
ECHA InfoCard	100.033.319
PubChem	26038
Wikidata	Q421443
properties
Molar mass	312.502 g mol −1
Physical state	firmly
density	5.83 g cm −3
Melting point	797 ° C
solubility	very light in water (1242 g l −1 at 0 ° C)
safety instructions
H and P phrases	H: 317-334-341-350i-360D-372-410
	P: 201-261-273-280-308 + 313-501
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Nickel (II) iodide is a chemical compound of the elements nickel and iodine . The pure substance is a black, crystalline solid that melts at 797 ° C.

Extraction and presentation

Nickel (II) iodide can be obtained directly from the elements:

{\ displaystyle \ mathrm {Ni + I_ {2} \ longrightarrow NiI_ {2}}}

Another possibility of representation is the iodination of nickel (II) chloride with sodium iodide :

{\ displaystyle \ mathrm {NiCl_ {2} +2 \ NaI \ longrightarrow NiI_ {2} +2 \ NaCl}}

It is also possible to produce it by reacting nickel (II) hydroxide or nickel (II) carbonate with hydriodic acid .

{\ displaystyle \ mathrm {Ni (OH) _ {2} +2 \ HI \ longrightarrow NiI_ {2} +2 \ H_ {2} O}}

properties

Nickel (II) iodide crystallizes in the trigonal crystal system with the space group R 3 m (space group no. 166) and the lattice parameters a = 392.9 pm and c = 1981.1 pm, in the unit cell there are three formula units . The structure thus corresponds to the CdCl ₂ structure. Template: room group / 166

Nickel (II) iodide, like the other nickel halides except nickel (II) fluoride , dissolves in water to form the blue-green hexahydrate:

{\ displaystyle \ mathrm {NiI_ {2} +6 \ H_ {2} O \ longrightarrow [Ni (H_ {2} O) _ {6}] ^ {2 +} + 2 \ I ^ {-}}}

Its crystals dissolve quickly in air and turn brown with iodine deposition. The compound decomposes above 43 ° C. When heated on a water bath, it converts to the anhydrous form.

Individual evidence

↑ ^a ^b webelements.com: Nickeldiiodide , accessed on January 18, 2012.
↑ W. Segerblom: Tables of Properties of Over Fifteen Hundred Common Inorganic Substances. Verlag Read Books, 2010, ISBN 978-1-4455-9102-5 , p. 47 ( limited preview in Google book search).
↑ ^a ^b Datasheet Nickel (II) iodide hydrate (PDF) from Strem, accessed on December 25, 2012.
↑ ^a ^b data sheet nickel (II) iodide from Sigma-Aldrich , accessed on December 27, 2010 ( PDF ).
↑ ^a ^b Entry on nickel diiodide in the GESTIS substance database of the IFA , accessed on February 1, 2016(JavaScript required) .
↑ Entry on Nickel diiodide in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
^ Norman N. Greenwood, Alan Earnshaw: Chemistry of the elements. 1st edition. Wiley-VCH, Weinheim 1988, ISBN 3-527-26169-9 , p. 1476.
^ ^A ^b A. F. Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 102nd edition. Walter de Gruyter, Berlin 2007, ISBN 978-3-11-017770-1 , p. 1713.
↑ ^a ^b Georg Brauer (Ed.) U. a .: Handbook of Preparative Inorganic Chemistry. 3rd, revised edition. Volume III, Ferdinand Enke, Stuttgart 1981, ISBN 3-432-87823-0 , p. 1688.
^ Jean D'Ans, Ellen Lax: Pocket book for chemists and physicists. 3. Elements, inorganic compounds and materials, minerals, volume 3. 4th edition. Springer, 1997, ISBN 3-540-60035-3 , p. 496 ( limited preview in the Google book search).

Web links

Crystal structures of nickel (II) bromide and iodide (PDF; 499 kB)

[Webelements-1] webelements.com: Nickeldiiodide , accessed on January 18, 2012.

[Segerblom-2] W. Segerblom: Tables of Properties of Over Fifteen Hundred Common Inorganic Substances. Verlag Read Books, 2010, ISBN 978-1-4455-9102-5 , p. 47 ( limited preview in Google book search).

[Strem-3] Datasheet Nickel (II) iodide hydrate (PDF) from Strem, accessed on December 25, 2012.

[sigmaaldrich-4] ta sheet nickel (II) iodide from Sigma-Aldrich , accessed on December 27, 2010 ( PDF ).

[GESTIS-5] Entry on nickel diiodide in the GESTIS substance database of the IFA , accessed on February 1, 2016(JavaScript required) .

[CLP_100.033.319-6] Entry on Nickel diiodide in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .

[elemente-7] Norman N. Greenwood, Alan Earnshaw: Chemistry of the elements. 1st edition. Wiley-VCH, Weinheim 1988, ISBN 3-527-26169-9 , p. 1476.

[howi-8] A ^b A. F. Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 102nd edition. Walter de Gruyter, Berlin 2007, ISBN 978-3-11-017770-1 , p. 1713.

[brauer-9] Georg Brauer (Ed.) U. a .: Handbook of Preparative Inorganic Chemistry. 3rd, revised edition. Volume III, Ferdinand Enke, Stuttgart 1981, ISBN 3-432-87823-0 , p. 1688.

[Lax-10] Jean D'Ans, Ellen Lax: Pocket book for chemists and physicists. 3. Elements, inorganic compounds and materials, minerals, volume 3. 4th edition. Springer, 1997, ISBN 3-540-60035-3 , p. 496 ( limited preview in the Google book search).