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Nickel(II) chloride

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(Redirected from Nickel dichloride)
Nickel chloride
Nickel(II) chloride hexahydrate
Hexahydrate

Anhydrous
Names
IUPAC name Nickel(II) chloride
Other names Nickelous chloride, nickel(II) salt of hydrochloric acid
Identifiers
CAS Number
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.028.858 Edit this at Wikidata
EC Number
  • 231-743-0
KEGG
PubChem CID
RTECS number
  • QR6480000
UNII
UN number 3288 3077
CompTox Dashboard (EPA)
InChI
  • InChI=1S/2ClH.Ni/h2*1H;/q;;+2/p-2Key: QMMRZOWCJAIUJA-UHFFFAOYSA-L
  • InChI=1/2ClH.Ni/h2*1H;/q;;+2/p-2Key: QMMRZOWCJAIUJA-NUQVWONBAR
SMILES
  • anhydrous: ..
  • hexahydrate: Cl(Cl)()()().O.O
Properties
Chemical formula NiCl2
Molar mass 129.5994 g/mol (anhydrous)
237.69 g/mol (hexahydrate)
Appearance yellow-brown crystals
deliquescent (anhydrous)
green crystals (hexahydrate)
Odor odorless
Density 3.55 g/cm (anhydrous)
1.92 g/cm (hexahydrate)
Melting point 1,001 °C (1,834 °F; 1,274 K) (anhydrous)
140 °C (hexahydrate)
Solubility in water anhydrous
67.5 g/100 mL (25 °C)
87.6 g/100 mL (100 °C)
hexahydrate
282.5 g/100 mL (25 °C)
578.5 g/100 mL (100 °C)
Solubility 0.8 g/100 mL (hydrazine)
soluble in ethylene glycol, ethanol, ammonium hydroxide
insoluble in ammonia, nitric acid
Acidity (pKa) 4 (hexahydrate)
Magnetic susceptibility (χ) +6145.0·10 cm/mol
Structure
Crystal structure Monoclinic
Coordination geometry octahedral at Ni
Thermochemistry
Std molar
entropy
(S298)
107 J·mol·K
Std enthalpy of
formation
fH298)
−316 kJ·mol
Hazards
Occupational safety and health (OHS/OSH):
Main hazards Very toxic (T+)
Irritant (Xi)
Dangerous for the environment (N)
Carcinogen
GHS labelling:
Pictograms GHS06: ToxicGHS08: Health hazardGHS09: Environmental hazard
Signal word Danger
Hazard statements H301, H315, H317, H331, H334, H341, H350i, H360D, H372, H410
Precautionary statements P201, P202, P260, P261, P264, P270, P271, P272, P273, P280, P281, P285, P301+P310, P302+P352, P304+P340, P304+P341, P308+P313, P311, P314, P321, P330, P332+P313, P333+P313, P342+P311, P362, P363, P391, P403+P233, P405, P501
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
3 0 0
Flash point Non-flammable
Lethal dose or concentration (LD, LC):
LD50 (median dose) 105 mg/kg (rat, oral)
Safety data sheet (SDS) Fischer Scientific
Related compounds
Other anions Nickel(II) fluoride
Nickel(II) bromide
Nickel(II) iodide
Other cations Palladium(II) chloride
Platinum(II) chloride
Platinum(II,IV) chloride
Platinum(IV) chloride
Related compounds Cobalt(II) chloride
Copper(II) chloride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). ☒verify (what is  ?) Infobox references
Chemical compound

Nickel(II) chloride (or just nickel chloride) is the chemical compound NiCl2. The anhydrous salt is yellow, but the more familiar hydrate NiCl2·6H2O is green. Nickel(II) chloride, in various forms, is the most important source of nickel for chemical synthesis. The nickel chlorides are deliquescent, absorbing moisture from the air to form a solution. Nickel salts have been shown to be carcinogenic to the lungs and nasal passages in cases of long-term inhalation exposure.

Production and syntheses

Large scale production and uses of nickel chloride are associated with the purification of nickel from its ores. It is generated upon extraction nickel matte and residues obtained from roasting refining nickel-containing ores using hydrochloric acid. Electrolysis of nickel chloride solutions are used in the production of nickel metal. Other significant routes to nickel chloride arise from processing of ore concentrates such as various reactions involving copper chlorides:

NiS + 2 CuCl2 → NiCl2 + 2 CuCl + S
NiO + 2 HCl → NiCl2 + H2O

Laboratory routes

Nickel chloride is not usually prepared in the laboratory because it is inexpensive and has a long shelf-life. The yellowish dihydrate, NiCl2·2H2O, is produced by heating the hexahydrate between 66 and 133 °C. The hydrates convert to the anhydrous form upon heating in thionyl chloride or by heating under a stream of HCl gas. Simply heating the hydrates does not afford the anhydrous dichloride.

NiCl2·6H2O + 6 SOCl2 → NiCl2 + 6SO2 + 12HCl

The dehydration is accompanied by a color change from green to yellow.

In case one needs a pure compound without presence of cobalt, nickel chloride can be obtained by cautiously heating hexaamminenickel chloride:

[ Ni ( NH 3 ) 6 ] Cl 2 hexammine nickel   chloride 175 200 C NiCl 2 + 6 NH 3 {\displaystyle {\ce {{\overset {hexammine \atop nickel~chloride}{Cl2}}->NiCl2{}+6NH3}}}

Structure of NiCl2 and its hydrates

Structure of hydrated nickel chloride based on X-ray crystallography. Color code: red = O, green = Cl

NiCl2 adopts the CdCl2 structure. In this motif, each Ni center is coordinated to six Cl centers, and each chloride is bonded to three Ni(II) centers. In NiCl2 the Ni-Cl bonds have "ionic character". Yellow NiBr2 and black NiI2 adopt similar structures, but with a different packing of the halides, adopting the CdI2 motif.

In contrast, NiCl2·6H2O consists of separated trans- molecules linked more weakly to adjacent water molecules. Only four of the six water molecules in the formula is bound to the nickel, and the remaining two are water of crystallization, so the formula of nickel(II) chloride hexahydrate is ·2H2O. Cobalt(II) chloride hexahydrate has a similar structure. The hexahydrate occurs in nature as the very rare mineral nickelbischofite.

The dihydrate NiCl2·2H2O adopts a structure intermediate between the hexahydrate and the anhydrous forms. It consists of infinite chains of NiCl2, wherein both chloride centers are bridging ligands. The trans sites on the octahedral centers occupied by aquo ligands. A tetrahydrate NiCl2·4H2O is also known.

Reactions

Nickel(II) chloride solutions are acidic, with a pH of around 4 due to the hydrolysis of the Ni ion.

Coordination complexes

Color of various Ni(II) complexes in aqueous solution. From left to right, , , ,

Most of the reactions ascribed to "nickel chloride" involve the hexahydrate, although specialized reactions require the anhydrous form.

Reactions starting from NiCl2·6H2O can be used to form a variety of nickel coordination complexes because the H2O ligands are rapidly displaced by ammonia, amines, thioethers, thiolates, and organophosphines. In some derivatives, the chloride remains within the coordination sphere, whereas chloride is displaced with highly basic ligands. Illustrative complexes include:

Complex Color Magnetism Geometry
Cl2 blue/violet paramagnetic octahedral
violet paramagnetic octahedral
NiCl2(dppe) orange diamagnetic square planar
colorless diamagnetic square planar
Yellowish-green paramagnetic tetrahedral

NiCl2 is the precursor to acetylacetonate complexes Ni(acac)2(H2O)2 and the benzene-soluble (Ni(acac)2)3, which is a precursor to Ni(1,5-cyclooctadiene)2, an important reagent in organonickel chemistry.

In the presence of water scavengers, hydrated nickel(II) chloride reacts with dimethoxyethane (dme) to form the molecular complex NiCl2(dme)2. The dme ligands in this complex are labile.

Applications in organic synthesis

NiCl2 and its hydrate are occasionally useful in organic synthesis.

  • As a mild Lewis acid, e.g. for the regioselective isomerization of dienols:
General reaction scheme for the isomerisation of dienols
  • In combination with CrCl2 for the coupling of an aldehyde and a vinylic iodide to give allylic alcohols.
  • For selective reductions in the presence of LiAlH4, e.g. for the conversion of alkenes to alkanes.
  • As a precursor to Brown's P-1 and P-2 nickel boride catalyst through reaction with NaBH4.
  • As a precursor to finely divided Ni by reduction with Zn, for the reduction of aldehydes, alkenes, and nitro aromatic compounds. This reagent also promotes homo-coupling reactions, that is 2RX → R-R where R = aryl, vinyl.
  • As a catalyst for making dialkyl arylphosphonates from phosphites and aryl iodide, ArI:
ArI + P(OEt)3 → ArP(O)(OEt)2 + EtI

NiCl2-dme (or NiCl2-glyme) is used due to its increased solubility in comparison to the hexahydrate.

Application of NiCl2 precatalyst.

Safety

Nickel(II) chloride is irritating upon ingestion, inhalation, skin contact, and eye contact. Prolonged inhalation exposure to nickel and its compounds has been linked to increased cancer risk to the lungs and nasal passages.

References

  1. ^ Lide, David S. (2003). CRC Handbook of Chemistry and Physics, 84th Edition. CRC Press. pp. 4–71. ISBN 9780849304842.
  2. ^ Zumdahl, Steven S. (2009). Chemical Principles 6th Ed. Houghton Mifflin Company. p. A22. ISBN 978-0-618-94690-7.
  3. "Nickel metal and other compounds (as Ni)". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  4. ^ Grimsrud, Tom K; Andersen, Aage (2010). "Evidence of carcinogenicity in humans of water-soluble nickel salts". Journal of Occupational Medicine and Toxicology. 5 (1): 7. doi:10.1186/1745-6673-5-7. PMC 2868037. PMID 20377901.
  5. Kerfoot, Derek G. E. (2000). "Nickel". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a17_157. ISBN 978-3-527-30385-4.
  6. ^ Ward, Laird G. L. (1972). "Anhydrous Nickel(II) Halides and their Tetrakis(ethanol) and 1,2-Dimethoxyethane Complexes". Inorganic Syntheses. Vol. 13. pp. 154–164. doi:10.1002/9780470132449.ch30. ISBN 9780470132449.
  7. Pray, A. P. (1990). "Anhydrous Metal Chlorides". Inorganic Syntheses. Inorganic Syntheses. Vol. 28. pp. 321–2. doi:10.1002/9780470132593.ch80. ISBN 9780470132593.
  8. Karyakin, Yu.V. (1947). Pure chemicals. Manual for laboratory preparation of inorganic substances (in Russian) (Moscow, Leningrad "State Scientific Technical Publishing of Chemical Literature" ed.). p. 416.
  9. ^ Wells, A. F. Structural Inorganic Chemistry, Oxford Press, Oxford, United Kingdom, 1984.
  10. B. Morosin "An X-ray diffraction study on nickel(II) chloride dihydrate" Acta Crystallogr. 1967. volume 23, pp. 630-634. doi:10.1107/S0365110X67003305
  11. Gill, N. S. & Taylor, F. B. (1967). Tetrahalo Complexes of Dipositive Metals in the First Transition Series. Inorganic Syntheses. Vol. 9. pp. 136–142. doi:10.1002/9780470132401.ch37. ISBN 9780470132401.
  12. G. D. Stucky; J. B. Folkers; T. J. Kistenmacher (1967). "The Crystal and Molecular Structure of Tetraethylammonium Tetrachloronickelate(II)". Acta Crystallographica. 23 (6): 1064–1070. doi:10.1107/S0365110X67004268.
  13. Tien-Yau Luh, Yu-Tsai Hsieh Nickel(II) Chloride" in Encyclopedia of Reagents for Organic Synthesis (L. A. Paquette, Ed.) 2001 J. Wiley & Sons, New York. doi:10.1002/047084289X.rn012. Article Online Posting Date: April 15, 2001.
  14. Cornella, Josep; Edwards, Jacob T.; Qin, Tian; Kawamura, Shuhei; Wang, Jie; Pan, Chung-Mao; Gianatassio, Ryan; Schmidt, Michael; Eastgate, Martin D. (2016-02-24). "Practical Ni-Catalyzed Aryl–Alkyl Cross-Coupling of Secondary Redox-Active Esters". Journal of the American Chemical Society. 138 (7): 2174–2177. doi:10.1021/jacs.6b00250. PMC 4768290. PMID 26835704.

External links

Nickel compounds
Nickel(0)
Nickel(II)
Nickel(III)
Nickel(IV)
Salts and covalent derivatives of the chloride ion
HCl He
LiCl BeCl2 B4Cl4
B12Cl12
BCl3
B2Cl4
+BO3
C2Cl2
C2Cl4
C2Cl6
CCl4
+C
+CO3
NCl3
ClN3
+N
+NO3
ClxOy
Cl2O
Cl2O2
ClO
ClO2
Cl2O4
Cl2O6
Cl2O7
ClO4
+O
ClF
ClF3
ClF5
Ne
NaCl MgCl2 AlCl
AlCl3
Si5Cl12
Si2Cl6
SiCl4
P2Cl4
PCl3
PCl5
+P
S2Cl2
SCl2
SCl4
+SO4
Cl2 Ar
KCl CaCl
CaCl2
ScCl3 TiCl2
TiCl3
TiCl4
VCl2
VCl3
VCl4
VCl5
CrCl2
CrCl3
CrCl4
MnCl2
MnCl3
FeCl2
FeCl3
CoCl2
CoCl3
NiCl2 CuCl
CuCl2
ZnCl2 GaCl
GaCl3
GeCl2
GeCl4
AsCl3
AsCl5
+As
Se2Cl2
SeCl2
SeCl4
BrCl Kr
RbCl SrCl2 YCl3 ZrCl2
ZrCl3
ZrCl4
NbCl3
NbCl4
NbCl5
MoCl2
MoCl3
MoCl4
MoCl5
MoCl6
TcCl3
TcCl4
RuCl2
RuCl3
RuCl4
RhCl3 PdCl2 AgCl CdCl2 InCl
InCl2
InCl3
SnCl2
SnCl4
SbCl3
SbCl5
Te3Cl2
TeCl2
TeCl4
ICl
ICl3
XeCl
XeCl2
XeCl4
CsCl BaCl2 * LuCl3 HfCl4 TaCl3
TaCl4
TaCl5
WCl2
WCl3
WCl4
WCl5
WCl6
ReCl3
ReCl4
ReCl5
ReCl6
OsCl2
OsCl3
OsCl4
OsCl5
IrCl2
IrCl3
IrCl4
PtCl2
PtCl4
AuCl
(Au)2
AuCl3
Hg2Cl2
HgCl2
TlCl
TlCl3
PbCl2
PbCl4
BiCl3 PoCl2
PoCl4
AtCl Rn
FrCl RaCl2 ** LrCl3 RfCl4 DbCl5 SgO2Cl2 BhO3Cl Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og
 
* LaCl3 CeCl3 PrCl3 NdCl2
NdCl3
PmCl3 SmCl2
SmCl3
EuCl2
EuCl3
GdCl3 TbCl3 DyCl2
DyCl3
HoCl3 ErCl3 TmCl2
TmCl3
YbCl2
YbCl3
** AcCl3 ThCl3
ThCl4
PaCl4
PaCl5
UCl3
UCl4
UCl5
UCl6
NpCl3 PuCl3 AmCl2
AmCl3
CmCl3 BkCl3 CfCl3
CfCl2
EsCl2
EsCl3
FmCl2 MdCl2 NoCl2
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