While \(\mathrm{Ti}^{3^{+}}, \mathrm{V}^{3^{+}}, \mathrm{Fe}^{3+}\) and
\(\mathrm{Co}^{2^{+}}\)can afford a large num-
ber of tetrahedral complexes, \(\mathrm{Cr}^{3+}\) never does this, the reason
being
(a) crystal field stabilisation energy in octahedral vis-Ã -vis tetrahedral
\(\mathrm{Cr}^{3+}\) system plays the deciding role
(b) \(\mathrm{Cr}^{3^{+}}\)forces high crystal field splitting with a varieties
of ligands
(c) electronegativity of \(\mathrm{Cr}^{3+}\) is the largest among these
trivalent 3 d-metals and so chromium prefers to be associated with as many
ligands as its radius permits
(d) both (b) and (c)