you did not understand me, I think that d2 low spin should refer to situation when two electrons are paired, high spin is when thay are unpaird, in general, for me it make no sence to refer to d2 low spin (althuogh is maybe in some special case possible), it is in general same for d1 ,d2, d3, considering 1.Hundt rule, or I am wrong?
What makes you think that they would be paired?
A paired state, though possible, would be very unfavored for this configuration.
The lowest states would be the ones that have the electrons seperate and has the third empty. Low spin doesn't mean that the electrons are paired. Low spin just means that the energy of repulsion between paired electron is not greater than the energy required to have some of the electrons in the higher energy orbitals. In other words, the molecule wouldn't be any lower in energy with its electrons split between the two sets of orbitals. The molecules are trying to get their energy to the lowest state possible.
but in case of d2 there are three degenerated (same energy) orbitals t2g
(or at leest two) , what should be high-spin d2? It is only one state (I am not so sure for excaptions) possible , i am not sure that is posible to hawe one electron in t2g and one in eg orbitals (that will be higher energy)
if exceptions are posible how you will call dxy
1 and how you will call dxy
2 is the first one high spin (orbitals are of same energy) or low spin? is the second one high or low spin? the same situation is with d9, it is only one configuration possible t2g6 eg3, it is not low spin it is only one possible
I think that high and low spin classification is possible for d4,d5,d6,d7 configurations