Subsolidus phase relations in CuWO4–Gd2WO6 system

Reactivity in the solid state between CuWO4 and Gd2WO6 was investigated up to solidus line. Two new compounds with the formulas Cu3Gd2W4O18 and CuGd2W2O10 were synthesized. Cu3Gd2W4O18 and CuGd2W2O10 melt incongruently at 1173 and 1248 K, respectively. Cu3Gd2W4O18 crystallizes in the triclinic system. Its anion lattice is built by isolated groups [(W4O16)8−]. CuGd2W2O10 crystallizes in the monoclinic system and its anion lattice is formed by structure elements [(W2O9)6−]∞. The asymmetric EPR signals of Cu3Gd2W4O18 and CuGd2W2O10, characteristic for concentrated, conducting magnetic systems are the same (Gd3+ exchange interactions) but the antiferromagnetic interaction between Gd3+ ions is lower as compared to Gd2WO6. Resonance line attributed to Cu2+ ions is not observed in EPR spectra of Cu3Gd2W4O18 and CuGd2W2O10.

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