Potassium tetracyanonickelate

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Potassium tetracyanonickelate
Potassium tetracyanonickelate.svg
Potassium tetracyanonickelate.jpg
Names
Other names
Potassium tetracyanonickelate(II); dipotassium tetracyanonickelate
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.034.605 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 238-082-7
PubChem CID
UNII
  • InChI=1S/4CN.2K.Ni/c4*1-2;;;/q4*-1;2*+1;+2
    Key: LXWJYIBQIPSFSE-UHFFFAOYSA-N
  • [K+].[K+].N#C[Ni-2](C#N)(C#N)C#N
Properties
K2Ni(CN)4
Appearanceyellow solid
Hazards
GHS labelling:
GHS-pictogram-skull.svg GHS-pictogram-pollu.svg
Danger
H300, H310, H330, H410
P260, P262, P264, P270, P271, P273, P280, P284, P301+P310, P302+P350, P304+P340, P310, P320, P321, P322, P330, P361, P363, P391, P403+P233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Potassium tetracyanonickelate (IUPAC: Potassium tetracyanido nickelate(II)) is the inorganic compound with the formula K2Ni(CN)4. It is usually encountered as the monohydrate but the anhydrous salt is also known. Both are yellow, water-soluble, diamagnetic solids. The salt consists of potassium ions and the tetracyanonickelate coordination complex, which is square planar. The [Ni(CN)4]2- anions are arranged in a columnar structure with Ni---Ni distances of 4.294 Å, which is well beyond the sum of the van der Waals radius of the nickel cation. [1] This columnar structure resembles those of the other [M(CN)4]2- anions of the heavy congeners of the group 10 metals (M = Pd, Pt).

Contents

Preparation

Ball-and-stick model of the tetracyanonickelate ion Tetracyanonickelate(II)-3D-balls.png
Ball-and-stick model of the tetracyanonickelate ion

Potassium tetracyanonickelate is prepared by treating aqueous solutions of nickel(II) salts with potassium cyanide. The synthesis is often conducted stepwise, beginning with precipitating solid nickel dicyanide coordination polymer. This route allows removal of excess potassium salts: [2]

Ni2+ + 2 KCN → Ni(CN)2 + 2 K+
Ni(CN)2 + 2 KCN → K2[Ni(CN)4]

This procedure yields the monohydrate. That solid dehydrates at 100 °C.

Reactions

The N-terminus of the cyanide ligand is basic and nucleophilic. The complex binds four equivalents of boron trifluoride:

K2[Ni(CN)4] + 4 BF3 → K2[Ni(CNBF3)4]

Cyanide is a sufficient pi-acceptor ligand to allow reduction of K2Ni(CN)4 to the Ni(0) derivative. Thus, potassium in anhydrous ammonia affords the tetraanionic, tetrahedral Ni(0) derivative [Ni(CN)4]4-. [3]

K2[Ni(CN)4] + 2 K → K4[Ni(CN)4]

An intermediate in this conversion is K4[Ni2(CN)6], which features an Ni-Ni bond. [4]

Related Research Articles

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<span class="mw-page-title-main">Zinc cyanide</span> Chemical compound

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<span class="mw-page-title-main">Metal nitrosyl complex</span> Complex of a transition metal bonded to nitric oxide: Me–NO

Metal nitrosyl complexes are complexes that contain nitric oxide, NO, bonded to a transition metal. Many kinds of nitrosyl complexes are known, which vary both in structure and coligand.

<span class="mw-page-title-main">Tetraphenylphosphonium chloride</span> Chemical compound

Tetraphenylphosphonium chloride is the chemical compound with the formula [(C6H5)4P]Cl, abbreviated Ph4PCl or PPh4Cl or [PPh4]Cl, where Ph stands for phenyl. Tetraphenylphosphonium and especially tetraphenylarsonium salts were formerly of interest in gravimetric analysis of perchlorate and related oxyanions. This colourless salt is used to generate lipophilic salts from inorganic and organometallic anions. Thus, [Ph4P]+ is useful as a phase-transfer catalyst, again because it allows inorganic anions to dissolve in organic solvents.

<span class="mw-page-title-main">Potassium nonahydridorhenate</span> Chemical compound

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<span class="mw-page-title-main">Nickel(II) bis(acetylacetonate)</span> Coordination complex

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<span class="mw-page-title-main">Cyanonickelate</span> Class of chemical compounds

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The fluoronickelates are a class of chemical compounds containing an anion with nickel at its core, surrounded by fluoride ions which act as ligands. This makes it a fluoroanion. The nickel atom can be in a range of oxidation states from +2, +3 to +4. The hexafluoronickelate(IV)2− ion NiF62− contains nickel in the maximal +4 state, and is in octahedral coordination by the fluoride atoms. It forms a commercially available salt Potassium hexafluoronickelate(IV) K2NiF6. Solid double salts can also contain tetrafluoronickelate NiF4 eg K2NiF4.

<span class="mw-page-title-main">Transition metal nitrile complexes</span> Class of coordination compounds containing nitrile ligands (coordinating via N)

Transition metal nitrile complexes are coordination compounds containing nitrile ligands. Because nitriles are weakly basic, the nitrile ligands in these complexes are often labile.

Nickel dicyanide is the inorganic compound with a chemical formula Ni(CN)2. It is a gray-green solid that is insoluble in most solvents.

<span class="mw-page-title-main">Potassium octacyanomolybdate(IV)</span> Chemical compound

Potassium octacyanomolybdate(IV) is the inorganic salt with the formula K4[Mo(CN)8]. A yellow light-sensitive solid, it is the potassium salt of the cyanometalate with the coordination number eight. The complex anion consists of a Mo(IV) center bound to eight cyanide ligands resulting in an overall charge of −4, which is balanced with four potassium cations. The salt is often prepared as its dihydrate K4[Mo(CN)8].(H2O)2.

References

  1. Vannerberg, Nils Gosta (1964). "The Crystal Structure of K2Ni(CN)4" (PDF). Acta Chemica Scandinavica. 18 (10): 2385–2391. doi: 10.3891/acta.chem.scand.18-2385 . Retrieved 29 April 2016. ICSD number 24099
  2. Fernelius, W. C.; Burbage, Joseph J. (1946). "Potassium Tetracyanonickelate(II)". Inorganic Syntheses. Inorganic Syntheses. Vol. 2. pp. 227–228. doi:10.1002/9780470132333.ch73. ISBN   9780470132333.
  3. Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 426. ISBN   978-0-08-037941-8.
  4. Jarchow, O.; Schulz, H.; Nast, R. (1970). "Structure of the Anion in Solid K4[Ni2(CN)6]". Angewandte Chemie International Edition in English. 9: 71. doi:10.1002/anie.197000711.