Cobalt(II) cyanide

Cobalt(II) cyanide
Names
	IUPAC name Cobalt(II) cyanide
	Other names cobaltous cyanide
Identifiers
CAS Number	542-84-7 ; 20427-11-6 (dihydrate) ; 26292-31-9 (trihydrate) ;
3D model (JSmol)	Interactive image;
ChemSpider	61631 ;
ECHA InfoCard	100.008.028
PubChem CID	68336;
UNII	3300OC3VVZ ;
CompTox Dashboard (EPA)	DTXSID20969165 ;
	InChI InChI=1S/2CN.Co/c21-2;/q2-1;+2 Key: CWZOMTYLSNXUEL-UHFFFAOYSA-N ; InChI=1/2CN.Co/c21-2;/q2-1;+2 Key: CWZOMTYLSNXUEL-UHFFFAOYAR;
	SMILES [Co+2].[C-]#N.[C-]#N;
Properties
Chemical formula	Co(CN)2
Molar mass	110.968 g/mol
Appearance	deep-blue powder ; hygroscopic
Density	1.872 g/cm3 (anhydrous)
Melting point	220 °C (428 °F; 493 K) (decomposes)
Solubility in water	insoluble
Solubility	dihydrate ; degraded with dissolution by NaCN, KCN, NH4OH, HCl
Magnetic susceptibility (χ)	+3825·10−6 cm3/mol
Related compounds
Other anions	Cadmium chloride,; Cadmium iodide
Other cations	Zinc cyanide,; Calcium cyanide,; Magnesium cyanide
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Cobalt(II) cyanide is the inorganic compound with the empirical formula Co(CN)₂ and structural formula Co₃[Co(CN)₅]₂. It is a coordination polymer that has attracted intermittent attention over many years in the areas of inorganic synthesis and homogeneous catalysis.^[2] The anhydrous and octahydrate forms are both blue solids insoluble in water.

Preparation and structure

The octahydrate is prepared by the reaction between tetraethylammonium pentacyanocobaltate and cobalt(II) chloride:^[3]

2 (Et₄N)₃[Co(CN)₅] + 3 Co(H₂O)₆Cl₂ → [Co(H₂O)₆]₃[Co(CN)₅]₂ · 2H₂O↓ + 6 Et₄N⁺ + 6 Cl⁻

Heating of the octahydrate at 100 °C produces the anhydrous form.^[3] The anhydrous form can also be prepared from the reaction of cobalt(II) bromide and potassium cyanide or sodium cyanide in liquid ammonia, then heating the resulting ammoniate to 210 °C in ethyl benzoate.^[4]

The structural formula Co₃[Co(CN)₅]₂ shows that cobalt(II) cyanide consists of Co²⁺ and [Co(CN)₅]^3– (pentacyanocobaltate) ions,^[3] the latter of which also has cobalt in its +2 oxidation state.

Oxygenation and redox

A red trihydrated has also been reported,^[5] but this was later shown to be the oxygenated derivative containing the ion [Co(CN)₅(O₂)]^3–.^[6]^[7]^[8]

The oxygenated derivative is obtained as a reddish-brown precipitate by adding two equivalents of potassium cyanide to a solution of cobalt(II) salts in air.^[9] With excess cyanide, the red-brown solid dissolves to give pentacyanocobaltate, which oxidizes in the presence of oxygen to hexacyanocobaltate(III).^[2]^[8]

Uses

Cobalt(II) cyanide has been used as a precursor to dicobalt octacarbonyl.^[10]

References

^ Lide, David R., ed. (2006). CRC Handbook of Chemistry and Physics (87th ed.). Boca Raton, Florida: CRC Press. ISBN 0-8493-0487-3.
^ ^a ^b Kwiatek, Jack (1968). "Reactions Catalyzed by Pentacyanocobaltate(II)". Catalysis Reviews. 1: 37–72. doi:10.1080/01614946808064700.
^ ^a ^b ^c Beauvais, Laurance G.; Long, Jeffrey R. (2002-10-01). "Co₃[Co(CN)₅]₂: A Microporous Magnet with an Ordering Temperature of 38 K". Journal of the American Chemical Society. 124 (41): 12096–12097. doi:10.1021/ja027768z. ISSN 0002-7863.
^ Mosha, D. M. S. J. Chem. Soc. Pak. 1985, 7, 173.
^ Weiss, Armin; Rothenstein, W. (1963). "Cobalt(II) Cyanide, its Three-Demensional Frame-work Structure and Zeolitic Compounds". Angewandte Chemie International Edition. 2 (7): 396. doi:10.1002/anie.196303962.
^ Brown, Leo D.; Raymond, Kenneth N. (1975-11-01). ".sigma.-Bonded dioxygen adduct of the pentacyanocobaltate(II) anion. Crystal structure of tris(tetraethylammonium)dioxopentacyanocobaltate(II) pentahydrate". Inorganic Chemistry. 14 (11): 2595–2601. doi:10.1021/ic50153a003. ISSN 0020-1669.
^ White, D. A.; Solodar, A. J.; Baizer, M. M. (1972). "Tetraalkylammonium pentacyanocobaltates. Their preparation, properties, and reactivity". Inorganic Chemistry. 11 (9): 2160–2167. doi:10.1021/ic50115a034. ISSN 0020-1669.
^ ^a ^b Poskozim, Paul S. (1969). "The preparation of potassium hexacyanocobaltate(III)". Journal of Chemical Education. 46 (6): 384. doi:10.1021/ed046p384. ISSN 0021-9584.
^ Bigelow, John H.; Bailar Jr., John C. (1946). "Potassium Hexacyanocobaltate(III)". Inorganic Syntheses. Inorganic Syntheses. Vol. 2. pp. 225–227. doi:10.1002/9780470132333.ch72. ISBN 9780470132333. {{cite book}}: ISBN / Date incompatibility (help)
^ Sternberg, Heinz W.; Wender, Irving; Orchin, Milton; Lynch Jr., M. A.; Sesny, W. J. (1957). "Cobalt Tetracarbonyl Hydride". Inorganic Syntheses. Inorganic Syntheses. Vol. 5. pp. 192–195. doi:10.1002/9780470132364.ch55. ISBN 9780470132364. {{cite book}}: ISBN / Date incompatibility (help)

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[1] Lide, David R., ed. (2006). CRC Handbook of Chemistry and Physics (87th ed.). Boca Raton, Florida: CRC Press. ISBN 0-8493-0487-3.

[orgsyn-2] Kwiatek, Jack (1968). "Reactions Catalyzed by Pentacyanocobaltate(II)". Catalysis Reviews. 1: 37–72. doi:10.1080/01614946808064700.

[d295-3] Beauvais, Laurance G.; Long, Jeffrey R. (2002-10-01). "Co₃[Co(CN)₅]₂: A Microporous Magnet with an Ordering Temperature of 38 K". Journal of the American Chemical Society. 124 (41): 12096–12097. doi:10.1021/ja027768z. ISSN 0002-7863.

[4] Mosha, D. M. S. J. Chem. Soc. Pak. 1985, 7, 173.

[Weiss-5] Weiss, Armin; Rothenstein, W. (1963). "Cobalt(II) Cyanide, its Three-Demensional Frame-work Structure and Zeolitic Compounds". Angewandte Chemie International Edition. 2 (7): 396. doi:10.1002/anie.196303962.

[6] Brown, Leo D.; Raymond, Kenneth N. (1975-11-01). ".sigma.-Bonded dioxygen adduct of the pentacyanocobaltate(II) anion. Crystal structure of tris(tetraethylammonium)dioxopentacyanocobaltate(II) pentahydrate". Inorganic Chemistry. 14 (11): 2595–2601. doi:10.1021/ic50153a003. ISSN 0020-1669.

[7] White, D. A.; Solodar, A. J.; Baizer, M. M. (1972). "Tetraalkylammonium pentacyanocobaltates. Their preparation, properties, and reactivity". Inorganic Chemistry. 11 (9): 2160–2167. doi:10.1021/ic50115a034. ISSN 0020-1669.

[chemedu-8] Poskozim, Paul S. (1969). "The preparation of potassium hexacyanocobaltate(III)". Journal of Chemical Education. 46 (6): 384. doi:10.1021/ed046p384. ISSN 0021-9584.

[9] Bigelow, John H.; Bailar Jr., John C. (1946). "Potassium Hexacyanocobaltate(III)". Inorganic Syntheses. Inorganic Syntheses. Vol. 2. pp. 225–227. doi:10.1002/9780470132333.ch72. ISBN 9780470132333. {{cite book}}: ISBN / Date incompatibility (help)

[10] Sternberg, Heinz W.; Wender, Irving; Orchin, Milton; Lynch Jr., M. A.; Sesny, W. J. (1957). "Cobalt Tetracarbonyl Hydride". Inorganic Syntheses. Inorganic Syntheses. Vol. 5. pp. 192–195. doi:10.1002/9780470132364.ch55. ISBN 9780470132364. {{cite book}}: ISBN / Date incompatibility (help)

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Cobalt(II) cyanide

Preparation and structure

Oxygenation and redox

Uses

References

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