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The Structures of Pentamethyltantalum and ‐Antimony: One Square Pyramid and One Trigonal Bipyramid
Author(s) -
Haaland Arne,
Hammel Andreas,
Rypdal Kristin,
Verne Hans Peter,
Volden Hans Vidar,
Pulham Colin
Publication year - 1992
Publication title -
angewandte chemie international edition in english
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 0570-0833
DOI - 10.1002/anie.199214641
Subject(s) - trigonal bipyramidal molecular geometry , square pyramid , trigonal pyramidal molecular geometry , antimony , square pyramidal molecular geometry , pyramid (geometry) , crystallography , square (algebra) , ab initio , electron diffraction , chemistry , bipyramid , ab initio quantum chemistry methods , diffraction , molecule , crystal structure , geometry , physics , inorganic chemistry , optics , mathematics , organic chemistry
Unexpected structures for pentacoordinate d 0 metal complexes were revealed in these theoretical and experimental studies. Ab initio calculations on [TaH 5 ] and [Ta(CH 3 ) 5 ] ( 1 ) show that square‐pyramidal coordination is preferred over trigonal‐bipyramidal in both cases. This was also confirmed for the pentamethyl complex by gas‐phase electron diffraction experiments. In contrast, the main group element compound [Sb(CH 3 ) 5 ] ( 2 ) has a trigonal‐bipyramidal geometry which is, however, separated from the square‐pyramidal form by only a small energy barrier.