In the paramagnetic and tetrahedral complex [NiCl4]^2–, the nickel is in +2 oxidation state and the ion has the electronic configuration 3d8. The hybridisation scheme is as shown in figure.

${\mathrm{\mu }}_{\mathrm{B}.\mathrm{M}.}=\sqrt{\mathrm{n}(\mathrm{n}+2)}=\sqrt{2(2+2)}=\sqrt{8}=2.82 \mathrm{BM}$