Define the following term: Coordination polyhedron.

(N/A) Coordination polyhedron: The spatial arrangement of the ligands which are directly attached to the central ion/atom defines a coordination polyhedron about the central atom.
The most common coordination polyhedra are octahedral,square planar,and tetrahedral.

$Coordination \ Entity$	$Shape \ of \ Polyhedron$
$(i) \ [Co(NH_3)_6]^{3+}$	$Octahedral$
$(ii) \ [Ni(CO)_4]$	$Tetrahedral$
$(iii) \ [PtCl_4]^{2-}$	$Square \ planar$