Definition: In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.
Input: Molecules with this coordination number include the intermediate in the counterpart of the Eigen-Wilkins mechanism and the product of the rate-determining step of the SN1cb mechanism. Tren ligands enforce one geometry of this coordination number, which is exemplified by a complex consisting of a metal atom bonded to a scorpionate ligand and dppe. The failure of fluorine-19 NMR to distinguish between (*) axial and equatorial substituents in complexes with this coordination number led to the discovery that they can isomerize through Berry pseudorotation. Associative substitution reactions that go through intermediates of this coordination number experience the trans effect. Intermediates of this coordination number occur in dissociative substitution reactions of octahedral complexes. For 10 points, name this coordination number of square pyramidal and trigonal bipyramidal complexes.
Output:
Science