Phase diagram of the AgGaSe2–CdSe system and crystal structure of the AgCd2GaSe4 compound

Abstract The phase diagram of the quasi-binary AgGaSe 2 –CdSe system was constructed using differential-thermal and X-ray phase analyses. The phase diagram is of the eutectic type with the formation of solid solution ranges of the initial components. A new quaternary phase was established as a result of the ordering of the CdSe-based solid solution and its crystal structure was determined using X-ray powder diffraction. This compound crystallizes in the orthorhombic Pmn2 1 space group with the lattice parameters a =0.84049(4), b =0.71934(4), c =0.68434(4) nm. Atomic parameters were refined in the isotropic approximation ( R I =0.0674). Refinement of the crystal structure of the sample with 65 mol.% of CdSe content (annealed at 1020 K) was carried out. It crystallizes in the hexagonal P6 3 mc space group with the lattice parameters a =0.42088(2), c =0.68956(3) nm. Atomic parameters were refined in the isotropic approximation ( R I =0.0669).