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Observation of the Highest Coordination Number in Planar Species: Decacoordinated Ta©B10 and Nb©B10 Anions


  • We thank Dr. Boris B. Averkiev for the theoretical calculations of the relativistic spin–orbit splittings in TaB10 with the ADF software. This work was supported by the National Science Foundation (grant DMR-0904034 to L.S.W. and grant CHE-1057746 to A.I.B.). Computer time from the Center for High Performance Computing at USU and an allocation of computer time from the Center for High Performance Computing at the University of Utah are gratefully acknowledged. T.R.G. thanks Utah State University for the Vice President for Research Graduate Fellowship.


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Molecular wheels: Decacoordinated molecular wheels, Ta©B10 (see picture) and Nb©B10, showing the highest coordination number for the central atom in a planar environment at present, were produced in a laser-vaporization supersonic molecular beam and characterized by photoelectron spectroscopy and ab initio calculations. The highly symmetric Ta©B10 and Nb©B10 anions are doubly aromatic with six delocalized π electrons and ten delocalized σ electrons.