Laporte rule

The Laporte rule is a spectroscopic selection rule that only applies to centrosymmetric molecules and atoms . It says that if electronic transitions are allowed, the parity must change, i.e. either g → u (even to odd parity) or u → g (odd to even parity). Hence, when a molecule is centrosymmetric, transitions within a given set of p or d orbitals are forbidden.

Laporte's rule for tetrahedral complexes

Since tetrahedral complexes do not have a center of symmetry , the d orbitals are in an interference field . Compared to centrosymmetric octahedral complex, therefore, a loosening of Laporte rule and consequently higher yields absorption coefficient at a UV-Vis - absorption spectrum .

Individual evidence

1. ↑ ^{a b c} Gade, Lutz H .: coordination chemistry . Wiley-VCH, Weinheim 1998, ISBN 978-3-527-29503-6 , pp. 273-274 .