Among the following combinations of metal carbonyl clusters and their skeletal structures, identify the correct ones.

A. $$Co_6(CO)_{14}^{4-}\rightarrow$$ capped trigonal bipyramid​​

B. $$\text{Ni}_6(\text{CO})_{12}^{2-}$$→ trigonal antiprism​​

C. $$Rh_6C(CO)^{2-}_{15}\rightarrow$$ trigonal prism​

D. $$Os_6(CO)_{18}\rightarrow$$ octahedron​

Choose the correct answer from the options given below:

Correct option is B

​The structures of many polynuclear organometallic species are conveniently described in terms of the total valence electron count, also called the Mingos cluster valence electron count.

In A, Co has an electronic configuration of [Ar] 3d⁷4s². CO is a two electron donor. Negative charge means addition of electrons. Total electron count= 6×9+14×2+4=86. The cluster framework is an octahedron.

In B, Ni has an electronic configuration of [Ar] 3d⁸4s². CO is a two electron donor. Negative charge means addition of electrons. Total electron count= 10×6+12×2+2=86. 

In C, Rh has an electronic configuration of [Kr] 4d⁸5s¹. CO is a two electron donor. Negative charge means addition of electrons. C atom is a four electron donor. Total electron count= 9×6+4+15×2+2=90. The cluster framework is trigonal prism.

In D, Os has an electronic configuration of [Xe] 4f¹⁴5d⁶6s². CO is a two electron donor. Total electron count= 8×6+18×2=84. The cluster framework is an octahedron.

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