Crystallochemical and optical study of mixed alkaline earth-samarium fluorohalides of the lead fluoride chloride type

Single crystals X-ray diffraction was performed on five crystals with nominal compositions Sr12Sm12FCl, Sr12Ca12FCl, Sr23Ba13FCl13Br23, Sr12Sm12FCl12Br12 and Sr0.6Sm0.1Ca 0.3FCl. Population refinements confirm the presence of correlations between lattice constants and composition. A new correlation between the heavy halogen z value and the unit cell volume is found. Luminescence spectra of bivalent samarium in these crystals contribute to the structural characterization of these compounds.