K(Ti3Se4)2 crystallizes in the triclinic P-1 space group. K(1) is bonded in a 6-coordinate geometry to two equivalent Se(2), two equivalent Se(3), and two equivalent Se(4) atoms. There are three inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one Se(2), two equivalent Se(1), and three equivalent Se(4) atoms to form a mixture of face, corner, and edge-sharing TiSe6 octahedra. The corner-sharing octahedral tilt angles range from 42-53°. In the second Ti site, Ti(2) is bonded to one Se(3), two equivalent Se(1), and three equivalent Se(2) atoms to form a mixture of face, corner, and edge-sharing TiSe6 octahedra. The corner-sharing octahedral tilt angles range from 42-53°. In the third Ti site, Ti(3) is bonded to one Se(4), two equivalent Se(1), and three equivalent Se(3) atoms to form a mixture of face, corner, and edge-sharing TiSe6 octahedra. The corner-sharing octahedral tilt angles range from 42-53°. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded to two equivalent Ti(1), two equivalent Ti(2), and two equivalent Ti(3) atoms to form distorted SeTi6 pentagonal pyramids that share corners with two equivalent Se(2)KTi4 trigonal bipyramids, corners with two equivalent Se(3)KTi4 trigonal bipyramids, corners with two equivalent Se(4)KTi4 trigonal bipyramids, edges with three equivalent Se(2)KTi4 trigonal bipyramids, edges with three equivalent Se(3)KTi4 trigonal bipyramids, edges with three equivalent Se(4)KTi4 trigonal bipyramids, and faces with two equivalent Se(1)Ti6 pentagonal pyramids. In the second Se site, Se(2) is bonded to one K(1), one Ti(1), and three equivalent Ti(2) atoms to form distorted SeKTi4 trigonal bipyramids that share corners with two equivalent Se(1)Ti6 pentagonal pyramids, corners with three equivalent Se(2)KTi4 trigonal bipyramids, corners with three equivalent Se(3)KTi4 trigonal bipyramids, corners with three equivalent Se(4)KTi4 trigonal bipyramids, edges with three equivalent Se(1)Ti6 pentagonal pyramids,  an edgeedge with one Se(3)KTi4 trigonal bipyramid,  an edgeedge with one Se(4)KTi4 trigonal bipyramid, and edges with two equivalent Se(2)KTi4 trigonal bipyramids. In the third Se site, Se(3) is bonded to one K(1), one Ti(2), and three equivalent Ti(3) atoms to form distorted SeKTi4 trigonal bipyramids that share corners with two equivalent Se(1)Ti6 pentagonal pyramids, corners with three equivalent Se(2)KTi4 trigonal bipyramids, corners with three equivalent Se(3)KTi4 trigonal bipyramids, corners with three equivalent Se(4)KTi4 trigonal bipyramids, edges with three equivalent Se(1)Ti6 pentagonal pyramids,  an edgeedge with one Se(2)KTi4 trigonal bipyramid,  an edgeedge with one Se(4)KTi4 trigonal bipyramid, and edges with two equivalent Se(3)KTi4 trigonal bipyramids. In the fourth Se site, Se(4) is bonded to one K(1), one Ti(3), and three equivalent Ti(1) atoms to form distorted SeKTi4 trigonal bipyramids that share corners with two equivalent Se(1)Ti6 pentagonal pyramids, corners with three equivalent Se(2)KTi4 trigonal bipyramids, corners with three equivalent Se(3)KTi4 trigonal bipyramids, corners with three equivalent Se(4)KTi4 trigonal bipyramids, edges with three equivalent Se(1)Ti6 pentagonal pyramids,  an edgeedge with one Se(2)KTi4 trigonal bipyramid,  an edgeedge with one Se(3)KTi4 trigonal bipyramid, and edges with two equivalent Se(4)KTi4 trigonal bipyramids.
K(Ti3Se4)2 crystallizes in the triclinic P-1 space group. K(1) is bonded in a 6-coordinate geometry to two equivalent Se(2), two equivalent Se(3), and two equivalent Se(4) atoms. Both K(1)-Se(2) bond lengths are 3.36 Å. Both K(1)-Se(3) bond lengths are 3.35 Å. Both K(1)-Se(4) bond lengths are 3.37 Å. There are three inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one Se(2), two equivalent Se(1), and three equivalent Se(4) atoms to form a mixture of face, corner, and edge-sharing TiSe6 octahedra. The corner-sharing octahedral tilt angles range from 42-53°. The Ti(1)-Se(2) bond length is 2.71 Å. There is one shorter (2.63 Å) and one longer (2.64 Å) Ti(1)-Se(1) bond length. There are a spread of Ti(1)-Se(4) bond distances ranging from 2.56-2.58 Å. In the second Ti site, Ti(2) is bonded to one Se(3), two equivalent Se(1), and three equivalent Se(2) atoms to form a mixture of face, corner, and edge-sharing TiSe6 octahedra. The corner-sharing octahedral tilt angles range from 42-53°. The Ti(2)-Se(3) bond length is 2.71 Å. Both Ti(2)-Se(1) bond lengths are 2.64 Å. There are a spread of Ti(2)-Se(2) bond distances ranging from 2.55-2.58 Å. In the third Ti site, Ti(3) is bonded to one Se(4), two equivalent Se(1), and three equivalent Se(3) atoms to form a mixture of face, corner, and edge-sharing TiSe6 octahedra. The corner-sharing octahedral tilt angles range from 42-53°. The Ti(3)-Se(4) bond length is 2.68 Å. Both Ti(3)-Se(1) bond lengths are 2.65 Å. There is one shorter (2.56 Å) and two longer (2.58 Å) Ti(3)-Se(3) bond lengths. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded to two equivalent Ti(1), two equivalent Ti(2), and two equivalent Ti(3) atoms to form distorted SeTi6 pentagonal pyramids that share corners with two equivalent Se(2)KTi4 trigonal bipyramids, corners with two equivalent Se(3)KTi4 trigonal bipyramids, corners with two equivalent Se(4)KTi4 trigonal bipyramids, edges with three equivalent Se(2)KTi4 trigonal bipyramids, edges with three equivalent Se(3)KTi4 trigonal bipyramids, edges with three equivalent Se(4)KTi4 trigonal bipyramids, and faces with two equivalent Se(1)Ti6 pentagonal pyramids. In the second Se site, Se(2) is bonded to one K(1), one Ti(1), and three equivalent Ti(2) atoms to form distorted SeKTi4 trigonal bipyramids that share corners with two equivalent Se(1)Ti6 pentagonal pyramids, corners with three equivalent Se(2)KTi4 trigonal bipyramids, corners with three equivalent Se(3)KTi4 trigonal bipyramids, corners with three equivalent Se(4)KTi4 trigonal bipyramids, edges with three equivalent Se(1)Ti6 pentagonal pyramids,  an edgeedge with one Se(3)KTi4 trigonal bipyramid,  an edgeedge with one Se(4)KTi4 trigonal bipyramid, and edges with two equivalent Se(2)KTi4 trigonal bipyramids. In the third Se site, Se(3) is bonded to one K(1), one Ti(2), and three equivalent Ti(3) atoms to form distorted SeKTi4 trigonal bipyramids that share corners with two equivalent Se(1)Ti6 pentagonal pyramids, corners with three equivalent Se(2)KTi4 trigonal bipyramids, corners with three equivalent Se(3)KTi4 trigonal bipyramids, corners with three equivalent Se(4)KTi4 trigonal bipyramids, edges with three equivalent Se(1)Ti6 pentagonal pyramids,  an edgeedge with one Se(2)KTi4 trigonal bipyramid,  an edgeedge with one Se(4)KTi4 trigonal bipyramid, and edges with two equivalent Se(3)KTi4 trigonal bipyramids. In the fourth Se site, Se(4) is bonded to one K(1), one Ti(3), and three equivalent Ti(1) atoms to form distorted SeKTi4 trigonal bipyramids that share corners with two equivalent Se(1)Ti6 pentagonal pyramids, corners with three equivalent Se(2)KTi4 trigonal bipyramids, corners with three equivalent Se(3)KTi4 trigonal bipyramids, corners with three equivalent Se(4)KTi4 trigonal bipyramids, edges with three equivalent Se(1)Ti6 pentagonal pyramids,  an edgeedge with one Se(2)KTi4 trigonal bipyramid,  an edgeedge with one Se(3)KTi4 trigonal bipyramid, and edges with two equivalent Se(4)KTi4 trigonal bipyramids.