TM complexes with two or more open-shell metal ions connected via a bridging ligand can exhibit strong electron correlation due to the overlap of magnetic orbitals and associated magnetic interactions (ferro or anti-ferro) between the spin centers, particularly with short 1-2 atom bridges. In 1994, Hughes et al. studied the variable temperature Figure . [( 5 -C5Me5)Cr II (µ 2 : 5 -P 5 )Cr II ( 5 -C5Me5)] + complex. Color code-green: Cr, orange: P, deep grey: C and light grey: H. magnetic susceptibility of a dimeric triple-decker Cr(II) complex [( 5 -C5Me5)Cr(µ 2 : 5 -P )Cr( 5 -C5Me5)] + (henceforth "the dimer;" Figure ) and reported that the dimer behaves as two isolated S = 1 systems at high temperature (160 K-295 K). In a subsequent study in 2007, Goeta et al. reported molecular structures of the dimer obtained by Xray diffractometry (XRD) at sixteen different temperatures spanning the spin crossover region indicated from magnetic susceptibility experiments (i.e., the T vs. T curve). Interestingly, the XRD experiments showed two different, independent dimeric units coexisting in the unit cell over the temperature range from 12 to 160 K. One unit (cation I) is characterized by an internuclear distance between the two Cr ions that progressively decreases as the temperature is lowered, whereas the other unit (cation II) is characterized by a near-constant Cr-Cr distance as the temperature decreases, followed by an abruptly shorter Cr-Cr distance at 12 K; this behavior is mapped against the experimental magnetic susceptibility curve in Figure These two possibilities cannot be resolved solely from the experimental data. Here, we provide quantitative insight into the relative importance of these effects using the toolkit of computational quantum chemistry.