Abstract
This paper classifies 120 emission lines resulting from 2s22pn-2s2pn+1 transitions in elements in the period between calcium and iron isoelectronic with Fe XVIII to Fe XXI. From the data presented energy levels of terms arising from the ground configuration can be calculated which can be of use in the prediction of the wavelengths of forbidden lines of astrophysical interest. A further fifty 2s22pn-2s22pn-1 3d emission lines are classified in the same ions; these will permit the identification of the strongest Fe XVIII to XXIV solar flare emission lines when higher resolution solar spectra become available.