K2AgIn3Se6 crystallizes in the monoclinic C2/c space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 7-coordinate geometry to one Se(1), one Se(2), one Se(3), one Se(4), one Se(5), and two equivalent Se(6) atoms. In the second K site, K(2) is bonded in a 7-coordinate geometry to one Se(1), one Se(2), one Se(3), one Se(4), one Se(6), and two equivalent Se(5) atoms. Ag(1) is bonded to one Se(1), one Se(2), one Se(3), and one Se(4) atom to form AgSe4 tetrahedra that share corners with two equivalent In(1)Se4 tetrahedra, corners with two equivalent In(2)Se4 tetrahedra, corners with two equivalent In(3)Se4 tetrahedra, and corners with two equivalent In(4)Se4 tetrahedra. There are four inequivalent In sites. In the first In site, In(1) is bonded to one Se(2), one Se(4), one Se(5), and one Se(6) atom to form InSe4 tetrahedra that share  a cornercorner with one In(2)Se4 tetrahedra,  a cornercorner with one In(3)Se4 tetrahedra, corners with two equivalent Ag(1)Se4 tetrahedra, and corners with two equivalent In(4)Se4 tetrahedra. In the second In site, In(2) is bonded to two equivalent Se(3) and two equivalent Se(4) atoms to form InSe4 tetrahedra that share corners with two equivalent In(1)Se4 tetrahedra, corners with two equivalent In(4)Se4 tetrahedra, and corners with four equivalent Ag(1)Se4 tetrahedra. In the third In site, In(3) is bonded to two equivalent Se(1) and two equivalent Se(2) atoms to form InSe4 tetrahedra that share corners with two equivalent In(1)Se4 tetrahedra, corners with two equivalent In(4)Se4 tetrahedra, and corners with four equivalent Ag(1)Se4 tetrahedra. In the fourth In site, In(4) is bonded to one Se(1), one Se(3), one Se(5), and one Se(6) atom to form InSe4 tetrahedra that share  a cornercorner with one In(2)Se4 tetrahedra,  a cornercorner with one In(3)Se4 tetrahedra, corners with two equivalent Ag(1)Se4 tetrahedra, and corners with two equivalent In(1)Se4 tetrahedra. There are six inequivalent Se sites. In the first Se site, Se(1) is bonded in a 5-coordinate geometry to one K(1), one K(2), one Ag(1), one In(3), and one In(4) atom. In the second Se site, Se(2) is bonded in a 5-coordinate geometry to one K(1), one K(2), one Ag(1), one In(1), and one In(3) atom. In the third Se site, Se(3) is bonded in a 5-coordinate geometry to one K(1), one K(2), one Ag(1), one In(2), and one In(4) atom. In the fourth Se site, Se(4) is bonded in a 5-coordinate geometry to one K(1), one K(2), one Ag(1), one In(1), and one In(2) atom. In the fifth Se site, Se(5) is bonded to one K(1), two equivalent K(2), one In(1), and one In(4) atom to form a mixture of distorted corner and edge-sharing SeK3In2 trigonal bipyramids. In the sixth Se site, Se(6) is bonded to one K(2), two equivalent K(1), one In(1), and one In(4) atom to form a mixture of distorted corner and edge-sharing SeK3In2 trigonal bipyramids.
K2AgIn3Se6 crystallizes in the monoclinic C2/c space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 7-coordinate geometry to one Se(1), one Se(2), one Se(3), one Se(4), one Se(5), and two equivalent Se(6) atoms. The K(1)-Se(1) bond length is 3.54 Å. The K(1)-Se(2) bond length is 3.52 Å. The K(1)-Se(3) bond length is 3.33 Å. The K(1)-Se(4) bond length is 3.35 Å. The K(1)-Se(5) bond length is 3.33 Å. There is one shorter (3.36 Å) and one longer (3.66 Å) K(1)-Se(6) bond length. In the second K site, K(2) is bonded in a 7-coordinate geometry to one Se(1), one Se(2), one Se(3), one Se(4), one Se(6), and two equivalent Se(5) atoms. The K(2)-Se(1) bond length is 3.34 Å. The K(2)-Se(2) bond length is 3.35 Å. The K(2)-Se(3) bond length is 3.54 Å. The K(2)-Se(4) bond length is 3.51 Å. The K(2)-Se(6) bond length is 3.35 Å. There is one shorter (3.35 Å) and one longer (3.65 Å) K(2)-Se(5) bond length. Ag(1) is bonded to one Se(1), one Se(2), one Se(3), and one Se(4) atom to form AgSe4 tetrahedra that share corners with two equivalent In(1)Se4 tetrahedra, corners with two equivalent In(2)Se4 tetrahedra, corners with two equivalent In(3)Se4 tetrahedra, and corners with two equivalent In(4)Se4 tetrahedra. The Ag(1)-Se(1) bond length is 2.65 Å. The Ag(1)-Se(2) bond length is 2.68 Å. The Ag(1)-Se(3) bond length is 2.65 Å. The Ag(1)-Se(4) bond length is 2.69 Å. There are four inequivalent In sites. In the first In site, In(1) is bonded to one Se(2), one Se(4), one Se(5), and one Se(6) atom to form InSe4 tetrahedra that share  a cornercorner with one In(2)Se4 tetrahedra,  a cornercorner with one In(3)Se4 tetrahedra, corners with two equivalent Ag(1)Se4 tetrahedra, and corners with two equivalent In(4)Se4 tetrahedra. The In(1)-Se(2) bond length is 2.59 Å. The In(1)-Se(4) bond length is 2.59 Å. The In(1)-Se(5) bond length is 2.61 Å. The In(1)-Se(6) bond length is 2.61 Å. In the second In site, In(2) is bonded to two equivalent Se(3) and two equivalent Se(4) atoms to form InSe4 tetrahedra that share corners with two equivalent In(1)Se4 tetrahedra, corners with two equivalent In(4)Se4 tetrahedra, and corners with four equivalent Ag(1)Se4 tetrahedra. Both In(2)-Se(3) bond lengths are 2.58 Å. Both In(2)-Se(4) bond lengths are 2.59 Å. In the third In site, In(3) is bonded to two equivalent Se(1) and two equivalent Se(2) atoms to form InSe4 tetrahedra that share corners with two equivalent In(1)Se4 tetrahedra, corners with two equivalent In(4)Se4 tetrahedra, and corners with four equivalent Ag(1)Se4 tetrahedra. Both In(3)-Se(1) bond lengths are 2.57 Å. Both In(3)-Se(2) bond lengths are 2.59 Å. In the fourth In site, In(4) is bonded to one Se(1), one Se(3), one Se(5), and one Se(6) atom to form InSe4 tetrahedra that share  a cornercorner with one In(2)Se4 tetrahedra,  a cornercorner with one In(3)Se4 tetrahedra, corners with two equivalent Ag(1)Se4 tetrahedra, and corners with two equivalent In(1)Se4 tetrahedra. The In(4)-Se(1) bond length is 2.59 Å. The In(4)-Se(3) bond length is 2.59 Å. The In(4)-Se(5) bond length is 2.60 Å. The In(4)-Se(6) bond length is 2.61 Å. There are six inequivalent Se sites. In the first Se site, Se(1) is bonded in a 5-coordinate geometry to one K(1), one K(2), one Ag(1), one In(3), and one In(4) atom. In the second Se site, Se(2) is bonded in a 5-coordinate geometry to one K(1), one K(2), one Ag(1), one In(1), and one In(3) atom. In the third Se site, Se(3) is bonded in a 5-coordinate geometry to one K(1), one K(2), one Ag(1), one In(2), and one In(4) atom. In the fourth Se site, Se(4) is bonded in a 5-coordinate geometry to one K(1), one K(2), one Ag(1), one In(1), and one In(2) atom. In the fifth Se site, Se(5) is bonded to one K(1), two equivalent K(2), one In(1), and one In(4) atom to form a mixture of distorted corner and edge-sharing SeK3In2 trigonal bipyramids. In the sixth Se site, Se(6) is bonded to one K(2), two equivalent K(1), one In(1), and one In(4) atom to form a mixture of distorted corner and edge-sharing SeK3In2 trigonal bipyramids.