The oxidation state of Ni and the number of metal-metal bonds in $\left[\mathrm{Ni}_{2}(\mathrm{CO})_{6}\right]^{2-}$ that are consistent with the 18 electron rule are
(a)Ni (-II), 1 bond
(b)Ni(IV), 2 bonds
(c)Ni(-I), 1 bond
(d)Ni(IV), 3 bonds
Answer
Answer: C ✓ checked by 4AB · confidence high
Explanation
[Ni₂(CO)₆]²⁻: each Ni(−I) has 11 + 6 = 17 electrons, so one Ni–Ni bond completes 18.