Different quasi-binary sections, binary sub-systems, and ternary sub-systems of the ternary systems LiF-(MeF2)-F-II-AlF3 (Me-II = Ca, Sr) were reported in a number of recent papers. From these data it is likely, that CaAlF5 melts incongruently, but SrAlF5 melts congruently. The present paper confirms the incongruent melting of CaAlF5 by DTA measurements within the quasi-binary system CaF2-AlF3. Chen et al. construct an incorrect "quasi binary" section LiF-CaAlF5, outgoing from the wrong assumption of congruent melting of CaAlF5. (C) 2002 Elsevier Science B.V. All rights reserved.