A combined experimental and theoretical electron density study of the shortest trichromium metal wire, Cr-3(dpa)(4)Cl-2 (C2H5OC2H5)x(CH2Cl2)(1-x) (1, dpa = bis(2-pyridyl)amido), is reported. High resolution X-ray diffraction data has been collected both at 100 K using a conventional X-ray source (DS1) and at 15 K using a synchrotron X-ray source (DS2). The linear chromium string is terminated by Cl- ions at both ends, and each Cr atom is also coordinated by four N atoms from bridging dpa ligands. The two Cr-Cr bond distances are unequal at 100 K (with d(Cr-1-Cr-2) being 0.029 angstrom shorter than d(Cr-2-Cr-3)) but at 15 K they are almost equal (0.002 angstrom difference). Analysis of the slightly elongated thermal ellipsoids of the Cr-2 atom suggests that it is not due to disorder, but the presence of a shallow potential energy surface. Laplacian maps clearly show local valence shell charge concentration (VSCC) in the electron density along the bisector of the equatorial Cr-N bonds. Integration over the atomic basins indicates that Cr-2 has smaller atomic charge and volume than Cr-1 and Cr-3. The topological characterization of the Cr-Cr bonds indicates partly covalent characters with electron density at the bond critical point of similar to 0.3 e angstrom(-3) and negative total energy density. The delocalization index of Cr-Cr is 0.8 for Cr-1-Cr-2 and 0.08 for Cr-1-Cr-3. Second-order perturbation analysis shows high stabilization energy of the Cr-Cr bonds (E-2 similar to 190 kcal mol(-1). Delocalization indices and source function and natural bond orbital analyses are all indicative of localized Cr-Cr bonding interactions.