In the abstract to the original Jahn-Teller paper (at https://royalsocietypublishing.org/doi/10.1098/rspa.1937.0142) it states: "We shall show that stability and degeneracy are not possible simultaneously unless the molecule is a linear one." Thus the Jahn-Teller effect is specifically about the removal of a degeneracy, and that that will always lower the ...
As far as I understand this is explained by Judd–Ofelt theory. When lanthanides are doped in the crystals, the crystal perturbation renders the Laporte selection rule inadequate to explain these transitions. The accumulated influence of the electrons and nucleus of the crystal host creates an electric field called crystal field. This crystal field generates ...
It is seen that Au(III) and Au(I) complexes are more stable than Au(II).I have an explanation but that is my observation-
Let's consider their electronic configuration.
Au → 5d10 6s1
Au+ → 5d10
Au2+ → 5d9
Au3+ → 5d8
So, if we split d-orbital into t2g and eg, we get
For Au →
For Au+ →
For Au2+ →
For Au3+ →
So, As you can see,
Au (I) - ...
I don't think it makes sense to compare Gold with Silver and Copper. In the 6th line of the periodic table, relativistic effects become important. And one of the relativistic effect is a contraction of the lengths. This effect is proportional to the sum of the two first quantum numbers. Gold outer orbitals are 4f 5d and 6s. Its configuration is [Xe] 4f14 ...