Nickel (II) chloride

Structural formula
	__ Ni 2+ __ Cl -
General
Surname	Nickel (II) chloride
other names	Nickel dichloride; Nickel chloride;
Molecular formula	NiCl 2 (anhydrous); NiCl 2 6 H 2 O (hexahydrate);
Brief description	yellow-orange crystals (anhydrous); green crystals (hexahydrate);
External identifiers / databases
EC number	231-743-0
ECHA InfoCard	100,028,858
PubChem	24385
ChemSpider	22796
Wikidata	Q29397
properties
Molar mass	129.62 g mol −1 (anhydrous); 237.70 g mol −1 (hexahydrate);
Physical state	firmly
density	3.55 g cm −3 (anhydrous); 1.92 g cm −3 (hexahydrate);
Melting point	Decomposition from 1001 ° C (anhydrous);
Vapor pressure	1.33 h Pa (anhydrous at 671 ° C)
solubility	very good in water (2540 g l −1 , hexahydrate at 20 ° C)
safety instructions
H and P phrases	H: 350i-360D-341-301-331-372-315-317-334-410
	P: 273-281-302 + 352-304 + 340-309 + 310
MAK	no classification as it is carcinogenic
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Nickel (II) chloride , NiCl ₂ , the nickel - salt of hydrochloric acid .

It forms yellow crystals which are readily soluble in water and ethanol . In addition to the anhydrous form (NiCl ₂ , anhydrate ), there is the hydrous nickel (II) chloride hexahydrate, NiCl ₂ · 6 H ₂ O, which forms green crystals. Furthermore, the nickel (II) chloride dihydrate, NiCl ₂ · 2 H ₂ O, and the nickel (II) chloride tetrahydrate, NiCl ₂ · 4 H ₂ O, are known.

properties

Nickel (II) chloride anhydrous

Nickel (II) chloride hexahydrate

The anhydrous nickel (II) chloride anhydrate is a highly hygroscopic salt. It has a CdCl ₂ structure . In contrast, nickel (II) chloride hexahydrate has a similar structure to cobalt (II) chloride hexahydrate and consists of individual trans - [NiCl ₂ (H ₂ O) ₄ ] molecules with weak bonds to the neighboring water molecules . Only four of the six water molecules from the formula are associated with the nickel. The remaining two are crystal waters . The hexahydrate crystallizes in the monoclinic crystal system in the space group C 2 / m (space group no. 12) with the lattice parameters a = 1023 pm , b = 705 pm, c = 657 pm and β = 122.17 °. In the unit cell contains two formula units . Template: room group / 12

Nickel (II) chloride is soluble in water , easily absorbable and poisonous. The LD ₅₀ in rats is 681 mg / kg and 105 mg / kg, respectively. The carcinogenicity (triggering of cancer) is also considered proven. In addition, there is a risk of sensitization (allergy) with all nickel compounds .

Manufacturing

The green nickel (II) chloride hexahydrate NiCl ₂ · 6 H ₂ O crystallizes from aqueous solutions by reacting hydrochloric acid (HCl) with nickel hydroxide Ni (OH) ₂ . It typically forms monoclinic prisms in the form of crystals.
Yellow, anhydrous NiCl ₂ can be obtained from the hexahydrate by drying in a stream of hydrogen chloride at a temperature of approx. 140 ° C or by heating in thionyl chloride .

{\ displaystyle \ mathrm {NiCl_ {2} \ cdot 6 \ H_ {2} O + 6 \ SOCl_ {2} \ longrightarrow NiCl_ {2} +6 \ SO_ {2} +12 \ HCl}}

The drainage is indicated by the change in color from green to yellow. The anhydrous form can also be produced from elemental nickel through prolonged exposure to HCl at temperatures above 550 ° C.

use

It is used as a dye in ceramics , in galvanic nickel plating and in the manufacture of nickel catalysts . Nickel (II) chloride is also a possible nickel electrolyte for nickel-plating metallic surfaces and a pickling agent in dyeing. The anhydrous form is used as an absorber for ammonia in gas mask filters.

Individual evidence

↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j Entry on nickel (II) chloride in the GESTIS substance database of the IFA , accessed on December 6, 2019(JavaScript required) .
↑ Entry on nickel dichloride 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 .
^ A. Ferrari, A. Braibanti, G. Bigliardi: Refinement of the crystal structure of NiCl ₂ and of unit-cell parameters of some anhydrous chlorides of divalent metals. In: Acta Crystallographica. 16, 1963, pp. 846-847, doi: 10.1107 / S0365110X6300222X .
^ ^A ^b A. F. Wells: Structural Inorganic Chemistry , Oxford Press, Oxford , United Kingdom , 1984.
↑ J. Mizuno: The Crystal Structure of Nickel Chloride Hexahydrate, NiCl ₂ · 6 H ₂ O , in: Journal of the Physical Society of Japan , 1961, 16 (8), p. 1574. bibcode : 1961JPSJ ... 16.1574M .
↑ Indian Journal of Pharmacology , 1991, Vol. 23, p. 153.
↑ Russian Pharmacology and Toxicology , 1969, Vol. 32, p. 102.

[GESTIS-1] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j Entry on nickel (II) chloride in the GESTIS substance database of the IFA , accessed on December 6, 2019(JavaScript required) .

[CLP_100.028.858-2] Entry on nickel dichloride 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 .

[Ferrari-3] A. Ferrari, A. Braibanti, G. Bigliardi: Refinement of the crystal structure of NiCl ₂ and of unit-cell parameters of some anhydrous chlorides of divalent metals. In: Acta Crystallographica. 16, 1963, pp. 846-847, doi: 10.1107 / S0365110X6300222X .

[Wells-4] A ^b A. F. Wells: Structural Inorganic Chemistry , Oxford Press, Oxford , United Kingdom , 1984.

[Mizuno-5] J. Mizuno: The Crystal Structure of Nickel Chloride Hexahydrate, NiCl ₂ · 6 H ₂ O , in: Journal of the Physical Society of Japan , 1961, 16 (8), p. 1574. bibcode : 1961JPSJ ... 16.1574M .

[6] Indian Journal of Pharmacology , 1991, Vol. 23, p. 153.

[7] Russian Pharmacology and Toxicology , 1969, Vol. 32, p. 102.