Four Valence Orbitals of Pentacoordinated Structure

Movement of the metal and apical ligand out of the plane relieves the repulsive interactions of nz2 = a, and it is substantially stabilized. At the same time, the degenerate 

The natural orientation of the 3/, trigonal bipyramidal system requires a reorientation of the coordinate frame relative to that used for the C, structures. The four valence orbitals resolve themselves into two degenerate groups (in ascending order) dxz, dyz) — e and dxy,dx — = e. The correspondence to the orbitals of the C4c structures is 

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