Question

colorless liquid metal carbonyl is *

Fe2(CO)9
Fe3(CO)12
Ni(CO)4
C02(CO)8​

Answer 1

The colourless liquid metal carbonyl is $[Ni(CO)_4]$.

• Generally, mononuclear metal carbonyls are colourless volatile liquids. Thus $[Ni(CO)_4]$ is a mononuclear carbonyl and it is colourless.
• Polynuclear metal carbonyls are coloured and the intensity of colour increases with an increase in the number of metal atoms.
• Thus the polynuclear carbonyl such as $[Fe_2(CO)_9]$,$[Fe_3(CO)_{12}]$ and $[Co_2(CO)_8]$ are coloured and the intensity of colour increases with increase in the number of metal atoms.