When the total position-spread tensor is partitioned according to spin (spin-partitioned total position-spread), it becomes a powerful tool to describe spin delocalization in the insulating regime. In Figure 4 is shown the longitudinal spin-partitioned total position-spread (Λ) computed at full configuration interaction level for the H 2 diatomic molecule. The horizontal line at 0 bohr divides the same spin (positive values) and different spin (negative values) contributions of the spin partitioned total position-spread. Unlike the spin-summed total position-spread that saturates to the atomic value for R>5, the spin-partitioned total position-spread diverges as R indicating that there is a strong spin delocalization. The spin-partitioned total position-spread can also be seen as a measure of how strong the electron correlation is.