Cobalt(II) cyanate
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| Section1 = {{Chembox Identifiers
| index1_label = isocyanate
| CASNo = 38150-63-9
| CASNo_Ref = {{cascite|correct|CAS}}
| PubChem1 = 15345298
| SMILES = C(#N)[O-].C(#N)[O-].[Co+2]
| InChI1=1S/2CNO.Co/c2*2-1-3;/q2*-1;+2
| InChIKey1 = JXDJYNWFLIUUIU-UHFFFAOYSA-N
| SMILES1 = C(=[N-])=O.C(=[N-])=O.[Co+2]
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| Section2 = {{Chembox Properties
| Formula = Co(OCN)2
| MolarMass = 142.97 g/mol
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| Section3 = {{Chembox Hazards
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| Section9 = {{Chembox Related
| OtherAnions = Cobalt(II) thiocyanate
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Cobalt(II) cyanate is the hypothetical inorganic compound with the formula Co(OCN)2.
The simple cobalt(II) cyanate has not been proven to be made. However, the tetraisocyanatocobalt(II) ion (Co(NCO)42-) is known and its blue color and is used as a qualitative test for cobalt(II) ions.
History
Cobalt(II) cyanate was claimed to have been produced in 1952 by carefully heating pyridine cobalt(II) cyanate under vacuum. The nature of the compound produced has not been elucidated by X-ray diffraction.{{cite journal |author1=Albert V. Logan |author2=David C. Bush |author3=Charles J. Rogers |title=The Heats of Formation of Cobalt(II) and Nickel(II) Pyridinated Cyanates and Thiocyanates |journal=Journal of the American Chemical Society |date=1952 |volume=74 |issue=16 |pages=4194–4195 |doi=10.1021/ja01136a069 |bibcode=1952JAChS..74.4194L |language=en}}
In contrast, the tetraisocyanatocobalt(II) ion (Co(NCO)42-) has been identified by X-ray crystallography and is widely known.{{cite journal |author1=Tim Peppel |author2=Alexander Hinz |author3=Philipp Thiele |author4=Monika Geppert-Rybczyńska |author5=Jochen K. Lehmann |author6=Martin Köckerling |title=Synthesis, Properties, and Structures of Low-Melting Tetraisocyanatocobaltate(II)-Based Ionic Liquids |journal=European Journal of Inorganic Chemistry |date=2017 |issue=5 |pages=885–893 |doi=10.1002/ejic.201601250 |language=en}} After being first produced in 1871, it has been used as a qualitative test for cobalt(II).{{cite journal |author1=C. W. Blomstrand |title=Zur Kenntniss der gepaarten Verbindungen des fünfatomigen Stickstoffs |journal=Journal für Praktische Chemie |date=1871 |volume=3 |issue=1 |pages=186–224 |doi=10.1002/prac.18710030119 |trans-title=Towards the knowledge of the paired compounds of five-atom nitrogen |language=de}}
Other cyanate complexes of cobalt have been discovered, such as tetrakis(pyridine)cobalt(II) cyanate.{{cite journal |author1=A.H. Norbury |title=Coordination Chemistry of the Cyanate, Thiocyanate, and Selenocyanate Ions |journal=Advances in Inorganic Chemistry and Radiochemistry |date=1975 |volume=17 |pages=231–386 |doi=10.1016/S0065-2792(08)60064-3 |isbn=978-0-12-023617-6 |language=en}}
Complexes
=Tetracyanatocobaltate(II)=
File:Cobalt cyanate complex.jpg
Multiple compounds of the related tetracyanatocobaltate(II) has been structurally elucidated, such as {{chem2|[Co(C5H5)2]2[Co(NCO)4]}}. All of these complexes have an intense blue color.{{cite journal |author1=Karin Ruhlandt-Senge |author2=Irina Sens |author3=Ulrich Müller |title=Die Bildung von [Co(C5H5)2]NO3 und [Co(C5H5)2]2[Co(NCO)4] aus Cobaltocen, Ozon und Acetonitril sowie deren Kristallstrukturen |journal=Zeitschrift für Naturforschung B |date=1991 |volume=46 |issue=12 |pages=1689–1693 |doi=10.1515/znb-1991-1218 |trans-title=Formation of [Co(C5H5)2]NO3 and [Co(C5H5)2]2[Co(NCO)4] from Cobaltocene, Ozone and Acetonitrile and their Crystal Structures |language=de|doi-access=free }}
Potassium tetraisocyanatocobaltate(II) has been produced by the reaction of potassium cyanate and cobalt(II) nitrate:{{cite journal |author1=F. Albert Cotton |author2=Margaret Goodgame |author1-link=F. Albert Cotton |title=Magnetic Investigations of Spin-free Cobaltous Complexes. V. Tetra-azido and Tetracyanato Cobaltate(II) Ions |journal=Journal of the American Chemical Society |date=1961 |volume=83 |issue=8 |pages=1777–1780 |doi=10.1021/ja01469a001 |bibcode=1961JAChS..83.1777C |language=en}}
:4 KOCN + Co(NO3)2 → K2[Co(NCO)4] + 2 KNO3
Tetracyanatocobaltate(II) salts with other counterions, such as cobaltcenium [Co(C5H5)]+ and EMIM are known.
=Other adducts=
Cobalt(II) cyanate complexes have been produced by the addition of potassium cyanate to a soluble cobalt salt, such as cobalt(II) chloride, followed by the addition of the complexing agent, such as pyridine, bipyridine,{{cite journal |author1=LI Jia |author2=Ling-Qian Kong |author3=Da-Cheng Li |title=cis-Bis-(2,2'-bipyrid-yl)dicyanato-cobalt(II) |journal=Acta Crystallographica Section E |date=2008 |volume=64 |issue=4 |page=582 |doi=10.1107/S1600536808007617 |pmid=21202031 |language=en|pmc=2960999 }} quinoline, and 2,6-dimethylpyrazine.{{cite journal |author1=A. B. P. Lever |author2=S. M. Nelson |title=An analysis of the electronic spectra of bis-amine cobalt halides: a novel effect of steric hindrance |journal=Journal of the Chemical Society A: Inorganic, Physical, Theoretical |date=1966 |pages=859–863 |doi=10.1039/J19660000859 |language=en}}
Structure
Although the simple cyanate is unknown, the structure of the tetracyanatocobaltate(II) ion has been elucidated. The [Co(NCO)4]2- ion consists of a nitrogen-bonded tetrahederal central cobalt atom. The cobalt-nitrogen bond length is about 1.96 Å.
References
{{reflist}}
{{Cobalt compounds}}
{{Cyanates}}