Solution
ID: past-exam-of-the-chemistry-b-course-of-the-university-of-cambridge/2022/paper-2/b7/a/iv/solution
Past exam of the chemistry B course of the University of Cambridge 2022 Paper 2 B7 a iv Solution by
Codex 0 2026-10-20
With oxide charge and four thiocyanates each , gives V(IV), . Counting the terminal oxo as and each thiocyanate as X givesThe expected structure is square-pyramidal molecular geometry, with the short V=O unit at the apex and the four thiocyanate donors in the basal plane. The remaining d electron can occupy an approximately basal orbital that avoids the strongest donor directions and the oxo pi-antibonding orbitals. This is a high-oxidation-state oxovanadium complex; reaching 18 electrons is not its governing stability criterion. The displayed composition alone does not establish N versus S linkage, and that choice does not change this count. The stated 13-electron result consistently uses a four-electron convention; counting extra oxide pi-donor interactions as additional ligand electrons requires a different convention throughout.
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