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. This has not been proven.[1]
In contrast, the tetraisocyanatocobalt(II) ion (Co(NCO)42-) has been identified by
X-ray crystallography and is widely known.[2] After being first produced in 1871, it has been used as a qualitative test for cobalt(II).[3]
Other cyanate complexes of cobalt have been discovered, such as tetrakis(pyridine)cobalt(II) cyanate.[4]
Complexes
Tetracyanatocobaltate(II)
Multiple compounds of the related tetracyanatocobaltate(II) has been structurally elucidated, such as [Co(C5H5)22[Co(NCO)4. All of these complexes have an intense blue color.[2][5]
Although the simple cyanate is unknown, the structure of the tetracyanatocobaltate(II) ion has been elucidated. The [Co(NCO)42- ion consists of a
nitrogen-bonded
tetrahederal central
cobalt atom. The cobalt-nitrogen bond length is about 1.96 Å.[2]
References
^Albert V. Logan; David C. Bush; Charles J. Rogers (1952). "The Heats of Formation of Cobalt(II) and Nickel(II) Pyridinated Cyanates and Thiocyanates". Journal of the American Chemical Society. 74 (16): 4194–4195.
doi:
10.1021/ja01136a069.
^
abcdTim Peppel; Alexander Hinz; Philipp Thiele; Monika Geppert-Rybczyńska; Jochen K. Lehmann; Martin Köckerling (2017). "Synthesis, Properties, and Structures of Low-Melting Tetraisocyanatocobaltate(II)-Based Ionic Liquids". European Journal of Inorganic Chemistry (5): 885–893.
doi:
10.1002/ejic.201601250.
^C. W. Blomstrand (1871). "Zur Kenntniss der gepaarten Verbindungen des fünfatomigen Stickstoffs" [Towards the knowledge of the paired compounds of five-atom nitrogen]. Journal für Praktische Chemie (in German). 3 (1): 186–224.
doi:
10.1002/prac.18710030119.
^A.H. Norbury (1975). "Coordination Chemistry of the Cyanate, Thiocyanate, and Selenocyanate Ions". Advances in Inorganic Chemistry and Radiochemistry. 17: 231–386.
doi:
10.1016/S0065-2792(08)60064-3.
^F. Albert Cotton; Margaret Goodgame (1961). "Magnetic Investigations of Spin-free Cobaltous Complexes. V. Tetra-azido and Tetracyanato Cobaltate(II) Ions". Journal of the American Chemical Society. 83 (8): 1777–1780.
doi:
10.1021/ja01469a001.
^A. B. P. Lever; S. M. Nelson (1966). "An analysis of the electronic spectra of bis-amine cobalt halides: a novel effect of steric hindrance". Journal of the Chemical Society A: Inorganic, Physical, Theoretical: 859–863.
doi:
10.1039/J19660000859.