Complex sentence: For an octahedral geometry, the five 3d orbitals of a transition metal split in t 2g and e g orbitals (see diagram) that are filled with the nine electrons corresponding to the d ^ 9 electronic configuration of Cu (II).
Split into simpler sentences: For an octahedral geometry, the five 3d orbitals partition into t 2g and e g orbitals (see diagram). These orbitals are occupied by nine electrons corresponding to the d ^ 9 electronic configuration of Cu (II).