Discuss the $[CoF_6]^{3-}$ complex species based on Valence Bond Theory $(VBT)$.

(N/A) $1$. The central metal ion is $Co^{3+}$,which has an electronic configuration of $[Ar] 3d^6$.
$2$. In the presence of the weak field ligand $F^-$,the $d$-electrons do not pair up.
$3$. The $Co^{3+}$ ion uses one $4s$,three $4p$,and two $4d$ orbitals to undergo $sp^3d^2$ hybridization.
$4$. Six pairs of electrons from six $F^-$ ions occupy these six $sp^3d^2$ hybrid orbitals.
$5$. Since the outer $4d$ orbitals are used,it is an outer orbital complex (high spin complex).
$6$. Due to the presence of four unpaired electrons in the $3d$ orbitals,the complex is paramagnetic.