# What atomic or hybrid orbital on C makes up the sigma bond between C and Cl in carbon tetrachloride, C Cl_4?

The hybrid $s {p}^{3}$ orbital
In the ground state the electron configuration is $1 {s}^{2} 2 {s}^{2} 2 {p}^{2}$
In the ground state Carbon can only form 2 bonds as in Carbon monoxide. $C O$ To form 4 bonds as in Carbon tetrachloride $C C l {l}_{4}$ Carbon has to blend all four orbitals the 1 s and 3 p s. This forms four equal $s {p}^{3}$ tetrahedral orbitals. Each of the Cl atoms forms a sigma bond with one of these four equal hybridized orbitals.