(પરમાણુ ક્રમાંક : $Ni = 28$)
$(I)\, [Ma_3b_2c]^{n \pm}\,\,\, (II)\, [M(AB)_3]^{n \pm}\,\,\, (III)\, [Ma_2b_2c_2]^{n \pm}$
$(I)\,\,\,-\,\,\,(II)\,\,\,-\,\,\,(III)$
$\left( {{C_2}O_4^{2 - } = } \right.$ ઓક્ઝલેટો $)$