Click on the images above to show the distortions in 3D
[CuF6]4- has a degenerate electronic ground state configuration (d9 configuration.) As a result the complex will distort in order to remove this degeneracy. It is able to distort in two ways; either an elongation or compression along the z-axis. Both will remove the degeneracy and will cause the Cu-F bonds to vary in length in the complex.