Orbital gold-copper complexes

It should be noted that all the above arguments apply also to the second and third rf-block transition series and that differences between the relative energies of the os, np and (n — )d orbitals may also be significant. For example there is an increase in the separation between the av and up orbitals in the series Cu, Ag and Au. This may account for the apparently greater stability of the 14-electron gold complexes PRsAuR compared to that of the copper analogues. 

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