[Morphic flip]

My question is straight forward 
How does an energy level diagram predict whether a complex is normal spinal or inverse spinal?
I understand how the diagram dictates high spin/weak field and low spin/strong field orbitals, but that`s about all.
I`ve looked on google, but can`t find clear straight explanations.
Thank`s.

[FeLiXe]

in octahedral complexes you have three stabilised an two destabilised orbitals

tetrahedral complexes have two stabilised and three destabilised orbitals

besides that the energy level difference in tetrahedral complexes is about 4/9 of that in octahedral complexes. so octahedral is generally better unless all orbitals are filled equally (d5 high spin or d10)

lets say you have three d-electrons (like Cr3+). then it's favorable to put them into three stabilised orbitals in octahedral complexes. in a tetrahedral complex (high spin) you have to put one into a destabilised orbital. therefore Cr3+ wants to go into an octahedral space Cr3+ spinels like MgCr2O4 will be normal.

if you consider Fe3+, you have five electrons. one in every orbital. no ligand field stabilisation energy. that means iron doesn't mind. every other electron configuration (except d10) rather goes octahedral. So Fe3+ will go tetrahedral and Magnetite is inverse.

If you want something "fun" to think of then tell me what Ni2+ does.