Английская Википедия:Cobalt(II) cyanate

Материал из Онлайн справочника
Перейти к навигацииПерейти к поиску

Шаблон:Chembox 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)

Файл:Cobalt cyanate complex.jpg
A solution of tetracyanatocobaltate(II)

Multiple compounds of the related tetracyanatocobaltate(II) has been structurally elucidated, such as Шаблон:Chem2. All of these complexes have an intense blue color.[2][5]

Potassium tetraisocyanatocobaltate(II) has been produced by the reaction of potassium cyanate and cobalt(II) nitrate:[6]

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.[2]

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,[7] quinoline, and 2,6-dimethylpyrazine.[8]

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.[2]

References

Шаблон:Reflist

Шаблон:Cobalt compounds Шаблон:Cyanates