A room-temperature structural phase diagram for the spinel Co3-x Mn x O4 (0 ≤ x ≤ 3) solid solution system was examined to study the cubic-tetragonal phase transition. The temperaturedependent magnetization was measured to identify the ferrimagnetic ordering at temperatures below T C An enhanced magneto-capacitance effect was observed around T C without any appreciable hysteretic behavior due to a variation in the applied magnetic field. The directional averaged complex atomic form factors of both the Co and the Mn ions at two different crystallographic sites of the oxide spinel structure near the K-absorption edges were extracted from the measured X-ray absorption spectra. Energy dispersive atomic form factors can be used to analyze X-ray diffraction data near the absorption edges to explore the detailed features coming from the local environmental effects