Chromium is the only member of the transition-group elements with a well developed Rydberg structure appearing in its 3p-absorption spectrum. New high-resolution measurements of Mn, Mn+, and Cr have revealed weak Rydberg structure in Mn+ and an analysis of the data shows that the anomalous Cr 3p absorption spectra is due to a unique relationship between its energy levels, and not to the previously supposed fact that Cr has an unpaired 4s electron.