DyAgSe2 crystallizes in the tetragonal I4_1md space group. Dy(1) is bonded to three equivalent Se(1) and three equivalent Se(2) atoms to form DySe6 octahedra that share corners with four equivalent Dy(1)Se6 octahedra, corners with three equivalent Ag(1)Se5 trigonal bipyramids, edges with four equivalent Dy(1)Se6 octahedra, and edges with six equivalent Ag(1)Se5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 8-10°. Ag(1) is bonded to two equivalent Se(1) and three equivalent Se(2) atoms to form AgSe5 trigonal bipyramids that share corners with three equivalent Dy(1)Se6 octahedra, corners with eight equivalent Ag(1)Se5 trigonal bipyramids, and edges with six equivalent Dy(1)Se6 octahedra. The corner-sharing octahedral tilt angles range from 0-75°. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to three equivalent Dy(1) and two equivalent Ag(1) atoms to form SeDy3Ag2 trigonal bipyramids that share corners with three equivalent Se(2)Dy3Ag3 octahedra, corners with eight equivalent Se(1)Dy3Ag2 trigonal bipyramids, and edges with six equivalent Se(2)Dy3Ag3 octahedra. The corner-sharing octahedral tilt angles range from 0-75°. In the second Se site, Se(2) is bonded to three equivalent Dy(1) and three equivalent Ag(1) atoms to form SeDy3Ag3 octahedra that share corners with four equivalent Se(2)Dy3Ag3 octahedra, corners with three equivalent Se(1)Dy3Ag2 trigonal bipyramids, edges with four equivalent Se(2)Dy3Ag3 octahedra, and edges with six equivalent Se(1)Dy3Ag2 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 8-12°.
DyAgSe2 crystallizes in the tetragonal I4_1md space group. Dy(1) is bonded to three equivalent Se(1) and three equivalent Se(2) atoms to form DySe6 octahedra that share corners with four equivalent Dy(1)Se6 octahedra, corners with three equivalent Ag(1)Se5 trigonal bipyramids, edges with four equivalent Dy(1)Se6 octahedra, and edges with six equivalent Ag(1)Se5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 8-10°. There are two shorter (2.82 Å) and one longer (2.83 Å) Dy(1)-Se(1) bond length. There are two shorter (2.82 Å) and one longer (2.88 Å) Dy(1)-Se(2) bond length. Ag(1) is bonded to two equivalent Se(1) and three equivalent Se(2) atoms to form AgSe5 trigonal bipyramids that share corners with three equivalent Dy(1)Se6 octahedra, corners with eight equivalent Ag(1)Se5 trigonal bipyramids, and edges with six equivalent Dy(1)Se6 octahedra. The corner-sharing octahedral tilt angles range from 0-75°. Both Ag(1)-Se(1) bond lengths are 2.91 Å. There is one shorter (2.80 Å) and two longer (2.83 Å) Ag(1)-Se(2) bond lengths. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to three equivalent Dy(1) and two equivalent Ag(1) atoms to form SeDy3Ag2 trigonal bipyramids that share corners with three equivalent Se(2)Dy3Ag3 octahedra, corners with eight equivalent Se(1)Dy3Ag2 trigonal bipyramids, and edges with six equivalent Se(2)Dy3Ag3 octahedra. The corner-sharing octahedral tilt angles range from 0-75°. In the second Se site, Se(2) is bonded to three equivalent Dy(1) and three equivalent Ag(1) atoms to form SeDy3Ag3 octahedra that share corners with four equivalent Se(2)Dy3Ag3 octahedra, corners with three equivalent Se(1)Dy3Ag2 trigonal bipyramids, edges with four equivalent Se(2)Dy3Ag3 octahedra, and edges with six equivalent Se(1)Dy3Ag2 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 8-12°.