[strider]

hi, i have just started crystal field theory and i was wondering if anyone can tell me what do t2g and eg stand for and are there any websites that elaborate the origin of these terms. i think it has something to do with group theory? help me with this
                                                           thank you

[FeLiXe]

I read something about this in Atkins, Physical Chemistry

the letters say how many orbitals of the same symmetry are combined
One orbital you call a or b (depending on something I don't know)
two orbitals you call e
three orbitals you call t
(I don't know where the letters come from)

If you have two sets of three orbitals, you call one of them t1 and the other t2

the g stands for German "gerade" meaning even. Like an even function the orbital stays the same after inversion. e.g. the s and d atomic orbitals are even.

u is for "ungerade" odd. the sign of the orbital changes due tu inversion. e.g. the p orbital is odd