In 1956, Dorothy Crowfoot Hodgkin discovered the structure of Vitamin B12 or its other name 'Cobalamin' because it has a transition metal, cobalt, as the central atom surrounded by complex amine groups and other complex functional groups as multidentate ligands.Based on the structure of Cobalamin, presented below in the picture, what could be the coordination number?
Correct answer: D. 6
- A. 3
- B. 4
- C. 5
- D. 6
Explanation
The structure of Vitamin B12, as described in the information, consists of cobalt as the central atom surrounded by six ligands: a tetradentate corrin ring system, a 5-deoxyadenose ligand on top, and a dimethyl benzimidazole ligand below. This arrangement of six ligands around the central cobalt atom forms an octahedral shape, and hence, the coordination number is 6.
This question appeared on the NUMS 2019 (cancelled sitting) paper, which you can sit online with every answer explained.
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