Carbon and germanium belong to the 14 th group. The maximum coordination number of carbon is less than…
Carbon and germanium belong to the 14 th group. The maximum coordination number of carbon is less than germanium, because of
larger size of germanium
electronegativity difference
availability of low-lying $d$-orbitals in germanium
electrical conductivity
Solution
Coordination number of an element depends on the availability of valence shells. Since, carbon is placed in 2nd period and electronic configuration of $\mathrm{C}_6$ is $1 s^2 2 s^2 2 p^2$. It do not have vacant $d$-orbital. Therefore, it has covalency of 4 . While germanium is placed in 3rd period in the periodic table.
Electronic configuration of $\mathrm{Ge}_{32}$ is $[\mathrm{Ar}] 3 d^{10} 4 s^2 4 p^2$. It has vacant $d$-orbital.
$\therefore$ Germanium can extend its coordination number.