The phase equilibria in pseudo-binary systems LiF-CaAlF5 and LiF-SrAlF5 have been studied by means of differential thermal analysis and X-ray diffraction. The two analogous phase diagrams show that the compounds LiCaAlF6 and LiSrAlF6 melt congruently with the composition of LiF:CaAlF5 = 1: 1 and LiF:SrAlF5 = 1: 1 at 814degreesC and 765degreesC, respectively. There are two eutectic relationships in the system LiF-CaAlF5, one between the compounds LiF and LiCaAlF6 with the eutectic temperature of 705degreesC, the other between LiCaAlF6 and CaAlF5 with the eutectic temperature of 781degreesC. The system LiF-SrAlF5 also has two eutectic relationships at the left or right side of the compound LiSrAlF6 with the eutectic temperatures of 673degreesC and 705degreesC, respectively. Using the feed materials with the stoichiometry compositions, large-size fluoride laser crystals Cr3+ :LiCaAlF6 and Cr3+ :LiSrAlF6, with high quality have been grown successfully by the vertical Bridgman method. (C) 2002 Elsevier Science B.V. All rights reserved.