Potassium hexafluoronickelate(IV)

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Potassium hexafluoronickelate(IV)
K2NiF6.svg
Names
IUPAC name
potassium hexafluoronickelate(IV)
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.153.655 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 625-130-0
  • InChI=1S/6FH.2K.Ni/h6*1H;;;/q;;;;;;2*+1;+4/p-6
  • [K+].[K+].F[Ni-2](F)(F)(F)(F)F
Properties
K2NiF6
Molar mass 250.880
Hazards [1]
GHS labelling:
GHS-pictogram-skull.svg GHS-pictogram-exclam.svg GHS-pictogram-silhouette.svg
Danger
H302, H312, H317, H331, H350
P201, P261, P280, P304+P340, P405, P501
Safety data sheet (SDS) External SDS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Potassium hexafluoronickelate(IV) is an inorganic compound with the chemical formula K
2
NiF
6
. It can be produced through the reaction of potassium fluoride, nickel dichloride, and fluorine.

It reacts violently with water, releasing oxygen. It dissolves in anhydrous hydrogen fluoride to produce a light-red solution. Potassium hexafluoronickelate(IV) decomposes at 350 °C, forming potassium hexafluoronickelate(III), nickel(II) fluoride, and fluorine: [2] [ better source needed ] [3]

Chemical structure of solid K2NiF6 as determined by X-ray crystallography. Mg2FeH6 from X-ray.jpg
Chemical structure of solid K2NiF6 as determined by X-ray crystallography.

Potassium hexafluoronickelate is a strong oxidant. It can turn chlorine pentafluoride and bromine pentafluoride into ClF+
6
and BrF+
6
, respectively: [4]

( X = Cl or Br , -60 °C , aHF = anhydrous hydrogen fluoride).

Potassium hexafluoronickelate decomposes at high temperatures to release fluorine gas; like terbium(IV) fluoride, the emitted fluorine is primarily monatomic rather than the typical diatomic. [5]

It adopts the structure seen for K2PtCl6 and Mg2FeH6. [6]

Related Research Articles

<span class="mw-page-title-main">Nickel(II) fluoride</span> Chemical compound

Nickel(II) fluoride is the chemical compound with the formula NiF2. It is an ionic compound of nickel and fluorine and forms yellowish to green tetragonal crystals. Unlike many fluorides, NiF2 is stable in air.

<span class="mw-page-title-main">Hydrogen fluoride</span> Chemical compound

Hydrogen fluoride (fluorane) is an inorganic compound with chemical formula HF. It is a very poisonous, colorless gas or liquid that dissolves in water to yield hydrofluoric acid. It is the principal industrial source of fluorine, often in the form of hydrofluoric acid, and is an important feedstock in the preparation of many important compounds including pharmaceuticals and polymers such as polytetrafluoroethylene (PTFE). HF is also widely used in the petrochemical industry as a component of superacids. Due to strong and extensive hydrogen bonding, it boils at near room temperature, which is much higher of a temperature than other hydrogen halides.

Bromine compounds are compounds containing the element bromine (Br). These compounds usually form the -1, +1, +3 and +5 oxidation states. Bromine is intermediate in reactivity between chlorine and iodine, and is one of the most reactive elements. Bond energies to bromine tend to be lower than those to chlorine but higher than those to iodine, and bromine is a weaker oxidising agent than chlorine but a stronger one than iodine. This can be seen from the standard electrode potentials of the X2/X couples (F, +2.866 V; Cl, +1.395 V; Br, +1.087 V; I, +0.615 V; At, approximately +0.3 V). Bromination often leads to higher oxidation states than iodination but lower or equal oxidation states to chlorination. Bromine tends to react with compounds including M–M, M–H, or M–C bonds to form M–Br bonds.

<span class="mw-page-title-main">Gold(V) fluoride</span> Chemical compound

Gold(V) fluoride is the inorganic compound with the formula Au2F10. This fluoride compound features gold in its highest known oxidation state. This red solid dissolves in hydrogen fluoride but these solutions decompose, liberating fluorine.

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

The dioxygenyl ion, O+
2
, is a rarely-encountered oxycation in which both oxygen atoms have a formal oxidation state of +1/2. It is formally derived from oxygen by the removal of an electron:

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

Manganese tetrafluoride, MnF4, is the highest fluoride of manganese. It is a powerful oxidizing agent and is used as a means of purifying elemental fluorine.

<span class="mw-page-title-main">Iridium(V) fluoride</span> Chemical compound

Iridium(V) fluoride, IrF5, is a chemical compound of iridium and fluorine. A highly reactive yellow low melting solid, it has a tetrameric structure, Ir4F20, which contains octahedrally coordinated iridium atoms. This structure is shared with RuF5 and OsF5. It can be prepared by the controlled decomposition of IrF6 or the reduction of IrF6 with silicon powder or H2 in anhydrous HF.

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

The tetrafluoroammonium cation is a positively charged polyatomic ion with chemical formula NF+
4
. It is equivalent to the ammonium ion where the hydrogen atoms surrounding the central nitrogen atom have been replaced by fluorine. Tetrafluoroammonium ion is isoelectronic with tetrafluoromethane CF
4
, trifluoramine oxide ONF
3
, tetrafluoroborate BF
4
anion and the tetrafluoroberyllate BeF2−
4
anion.

<span class="mw-page-title-main">Bismuth pentafluoride</span> Chemical compound

Bismuth pentafluoride is an inorganic compound with the formula BiF5. It is a white solid that is highly reactive. The compound is of interest to researchers but not of particular value.

Nitrogen pentafluoride is a theoretical compound of nitrogen and fluorine with the chemical formula NF5. It is hypothesized to exist based on the existence of the pentafluorides of the atoms below nitrogen in the periodic table, such as phosphorus pentafluoride. Theoretical models of the nitrogen pentafluoride molecule are either a trigonal bipyramidal covalently bound molecule with symmetry group D3h, or [NF4]+F, which would be an ionic solid.

Polyhalogen ions are a group of polyatomic cations and anions containing halogens only. The ions can be classified into two classes, isopolyhalogen ions which contain one type of halogen only, and heteropolyhalogen ions with more than one type of halogen.

<span class="mw-page-title-main">Neptunium(VI) fluoride</span> Chemical compound

Neptunium(VI) fluoride (NpF6) is the highest fluoride of neptunium, it is also one of seventeen known binary hexafluorides. It is a volatile orange crystalline solid. It is relatively hard to handle, being very corrosive, volatile and radioactive. Neptunium hexafluoride is stable in dry air but reacts vigorously with water.

Fluorine forms a great variety of chemical compounds, within which it always adopts an oxidation state of −1. With other atoms, fluorine forms either polar covalent bonds or ionic bonds. Most frequently, covalent bonds involving fluorine atoms are single bonds, although at least two examples of a higher order bond exist. Fluoride may act as a bridging ligand between two metals in some complex molecules. Molecules containing fluorine may also exhibit hydrogen bonding. Fluorine's chemistry includes inorganic compounds formed with hydrogen, metals, nonmetals, and even noble gases; as well as a diverse set of organic compounds. For many elements the highest known oxidation state can be achieved in a fluoride. For some elements this is achieved exclusively in a fluoride, for others exclusively in an oxide; and for still others the highest oxidation states of oxides and fluorides are always equal.

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">Trifluoramine oxide</span> Chemical compound

Trifluoramine oxide or Nitrogen trifluoride oxide (F3NO) is an inorganic molecule with strong fluorinating powers.

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

Praseodymium(IV) fluoride (also praseodymium tetrafluoride) is a binary inorganic compound, a highly oxidised metal salt of praseodymium and fluoride with the chemical formula PrF4.

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

The hexafluoroarsenate anion is a chemical species with formula AsF−6. Hexafluoroarsenate is relatively inert, being the conjugate base of the notional superacid hexafluoroarsenic acid.

<span class="mw-page-title-main">Protactinium(V) fluoride</span> Chemical compound

Protactinium(V) fluoride is a fluoride of protactinium with the chemical formula PaF5.

Nickel tetrafluoride is an inorganic compound with a chemical formula NiF4.

References

  1. "Potassium Hexafluoronickelate(IV)". American Elements . Retrieved December 19, 2018.
  2. (in Chinese)张青莲. 《无机化学丛书》第九卷:锰分族、铁系、铂系. 北京: 科学出版社. pp. P333. ISBN   7-03-002238-6.
  3. Stein, Lawrence; Neil, John M.; Alms, Gregory R. (November 1969). "Properties of potassium hexafluoronickelates(III) and -(IV). Absorption spectra of nickel(III) and -(IV) in hydrogen fluoride solutions". Inorganic Chemistry. 8 (11): 2472–2476. doi:10.1021/ic50081a045. ISSN   0020-1669.
  4. Schroer, Thorsten; Christe, Karl O. (2001). "Novel Synthesis of ClF6+ and BrF6+ Salts". Inorganic Chemistry. 40 (10): 2415–9. doi:10.1021/ic001024. PMID   11327921.
  5. Rau, J. V.; Chilingarov, N. S.; Leskiv, M. S.; Sukhoverkhov, V. F.; Rossi Albertini, V.; Sidorov, L. N. (August 2001). "Transition and rare earth metal fluorides as thermal sources of atomic and molecular fluorine". Le Journal de Physique IV. 11 (PR3): Pr3–109–Pr3-113. doi:10.1051/jp4:2001314.
  6. Taylor, J. C. "A comparison of profile decomposition and Rietveld methods for structurtal refinement with powder diffraction data" Zeitschrift für Kristallographie 1987, volume 181, p151-160.