Probably a stupid question, but for some reason I can't think of how to determine whether a complex is tetrahedral or octahedral given only UV-vis absorptions. We have [Co2(MIMT)2(NO3)2] and [Co2(MIMT)4(NO3)2], and I know (it's given) that the first one (absorption at 525 nm) is tetrahedral, so I can figure out the crystal field stabilization energy from there. The second one had an absorption at 545 nm. I have no idea how to take that number and determine whether the molecule is tetrahedral or octahedral (high-spin or low-spin). What do I do?