CHEM 324 Lecture Notes - Lecture 3: Trigonal Bipyramidal Molecular Geometry, Trigonal Planar Molecular Geometry, Coordination Geometry

• School: University of Victoria
• Department: Chemistry
• Course: CHEM 324
• Professor: Robin Hicks

Document Summary

Note that vsepr fails to predict geometries for compounds of the d-block elements. This is because lone pairs on the metals are not stereochemically active. E. g. the complex shown below has the six ligands arranged around the ru ion in an octahedral geometry. This is despite the fact that there are three lone pairs on the ru, i. e. the lone pairs do not influence the overall shape of the molecule. The kepert model (p646) predicts molecular shapes for a given coordination number based on minimizing repulsive interactions between ligands. Most common coordination numbers linear trigonal planar tetrahedral trigonal bipyramidal octahedral most favoured geometry minimizes repulsive interactions but has no mention of lone pairs. Bent will bring ligands closer together thus linear is best. The st(cid:396)u(cid:272)tu(cid:396)es listed a(cid:271)ove a(cid:396)e (cid:374)ot the o(cid:374)l(cid:455) possi(cid:271)ilities (cid:894)a(cid:374)d so(cid:373)e of the (cid:862)alte(cid:396)(cid:374)atives(cid:863) are in fact fairly common).