DODECACARBONYLTETRACOBALT Property

Melting point:

60°C (dec.)

Density 

2,09 g/cm³

RTECS 

GG3410000

form 

crystal

Specific Gravity

2.09

color 

black

Water Solubility 

slightly soluble H2O [CRC10]

Sensitive 

Air Sensitive

Exposure limits

ACGIH: TWA 0.02 mg/m3

Safety

Risk Statements 

23/24/25

Safety Statements 

23-36/37

RIDADR 

3466

HazardClass 

6.1

PackingGroup 

II

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Danger

Hazard statements

H228Flammable solid

H301Toxic if swalloed

H317May cause an allergic skin reaction

H331Toxic if inhaled

H351Suspected of causing cancer

Precautionary statements

P210Keep away from heat/sparks/open flames/hot surfaces. — No smoking.

P262Do not get in eyes, on skin, or on clothing.

P304+P340IF INHALED: Remove victim to fresh air and Keep at rest in a position comfortable for breathing.

P309IF exposed or if you feel unwell:

P310Immediately call a POISON CENTER or doctor/physician.

DODECACARBONYLTETRACOBALT Chemical Properties,Usage,Production

Uses

Catalyst precursor in the interand intramolecular Pauson-Khand reaction.

Chemical Properties

black crystal(s); air sensitive [DOU83] [STR93]

Preparation

Tetracobalt dodecacarbonyl is most conveniently prepared by thermal decomposition of the octacarbonyl at 50° in an inert atmosphere : 2Co2(CO)8 → Co4(CO)12+4CO at present it cannot be prepared direct from cobalt(II) salts and carbon monoxide. Treatment of Co4(CO)12 with alkali metals in tetrahydrofuran gives the green-yellow [Co6(CO)15]^2- ion which is slowly transformed into the red-brown [Co6(CO)14]^4- anion; these ions are oxidized in aqueous solution by iron(III) chloride to a mixture of carbonyls from which the black Co6(CO)16 can be extracted.

Structure and conformation

It consists of a tetrahedron of cobalt atoms ; three of these have two terminal CO groups and are bridged by CO groups, the other cobalt atom is bonded to three terminal CO groups and the other three cobalt atoms only. The infrared spectrum is considerably simpler than would be expected theoretically for such a structure and consequently a different structure has been proposed for Co4(CO)12 in solution. The carbonyl CO6(CO)16 has a similar infrared spectrum to, and is isomorphous with, Rh6(CO)16 so that it probably has the same structure.