EPR studies of Y0.03Ca0.97F2.03 : Gd3+ and Y0.03Cd0.97F2.03 : Gd3+ single crystals revealed the presence of Gd3+ ions embedded in yttrium clusters. The symmetry of the paramagnetic centers was determined, and the fine-structure parameters were estimated both experimentally and theoretically. (c) 2005 Pleiades Publishing, Inc.