K3RuP5Se10 crystallizes in the monoclinic P2_1/m space group. There are three inequivalent K sites. In the first K site, K(1) is bonded in a 8-coordinate geometry to one Se(1), three equivalent Se(2), and four equivalent Se(4) atoms. In the second K site, K(2) is bonded in a 12-coordinate geometry to one P(3), one Se(2), one Se(3), two equivalent Se(6), three equivalent Se(1), and four equivalent Se(5) atoms. In the third K site, K(3) is bonded in a 3-coordinate geometry to one Se(3) and four equivalent Se(4) atoms. Ru(1) is bonded to one P(4), two equivalent P(2), one Se(7), and two equivalent Se(5) atoms to form RuP3Se3 octahedra that share corners with two equivalent P(2)PRuSe2 tetrahedra. There are four inequivalent P sites. In the first P site, P(1) is bonded in a 3-coordinate geometry to one Se(7) and two equivalent Se(4) atoms. In the second P site, P(2) is bonded to one Ru(1), one P(2), one Se(3), and one Se(6) atom to form distorted PPRuSe2 tetrahedra that share  a cornercorner with one Ru(1)P3Se3 octahedra and corners with two equivalent P(2)PRuSe2 tetrahedra. The corner-sharing octahedral tilt angles are 63°. In the third P site, P(3) is bonded in a 3-coordinate geometry to one K(2), one Se(2), and two equivalent Se(5) atoms. In the fourth P site, P(4) is bonded in a 4-coordinate geometry to one Ru(1), one Se(1), and two equivalent Se(6) atoms. There are seven inequivalent Se sites. In the first Se site, Se(1) is bonded in a 5-coordinate geometry to one K(1), three equivalent K(2), and one P(4) atom. In the second Se site, Se(2) is bonded in a 5-coordinate geometry to one K(2), three equivalent K(1), and one P(3) atom. In the third Se site, Se(3) is bonded in a 3-coordinate geometry to one K(2), one K(3), and two equivalent P(2) atoms. In the fourth Se site, Se(4) is bonded in a 5-coordinate geometry to two equivalent K(1), two equivalent K(3), and one P(1) atom. In the fifth Se site, Se(5) is bonded in a 2-coordinate geometry to two equivalent K(2), one Ru(1), and one P(3) atom. In the sixth Se site, Se(6) is bonded in a 3-coordinate geometry to one K(2), one P(2), and one P(4) atom. In the seventh Se site, Se(7) is bonded in a 2-coordinate geometry to one Ru(1) and one P(1) atom.
K3RuP5Se10 crystallizes in the monoclinic P2_1/m space group. There are three inequivalent K sites. In the first K site, K(1) is bonded in a 8-coordinate geometry to one Se(1), three equivalent Se(2), and four equivalent Se(4) atoms. The K(1)-Se(1) bond length is 3.54 Å. There is one shorter (3.50 Å) and two longer (3.79 Å) K(1)-Se(2) bond lengths. There are two shorter (3.66 Å) and two longer (3.80 Å) K(1)-Se(4) bond lengths. In the second K site, K(2) is bonded in a 12-coordinate geometry to one P(3), one Se(2), one Se(3), two equivalent Se(6), three equivalent Se(1), and four equivalent Se(5) atoms. The K(2)-P(3) bond length is 3.62 Å. The K(2)-Se(2) bond length is 3.38 Å. The K(2)-Se(3) bond length is 3.90 Å. Both K(2)-Se(6) bond lengths are 3.62 Å. There is one shorter (3.32 Å) and two longer (3.77 Å) K(2)-Se(1) bond lengths. There are two shorter (3.73 Å) and two longer (3.80 Å) K(2)-Se(5) bond lengths. In the third K site, K(3) is bonded in a 3-coordinate geometry to one Se(3) and four equivalent Se(4) atoms. The K(3)-Se(3) bond length is 3.49 Å. There are two shorter (3.45 Å) and two longer (3.78 Å) K(3)-Se(4) bond lengths. Ru(1) is bonded to one P(4), two equivalent P(2), one Se(7), and two equivalent Se(5) atoms to form RuP3Se3 octahedra that share corners with two equivalent P(2)PRuSe2 tetrahedra. The Ru(1)-P(4) bond length is 2.30 Å. Both Ru(1)-P(2) bond lengths are 2.28 Å. The Ru(1)-Se(7) bond length is 2.64 Å. Both Ru(1)-Se(5) bond lengths are 2.62 Å. There are four inequivalent P sites. In the first P site, P(1) is bonded in a 3-coordinate geometry to one Se(7) and two equivalent Se(4) atoms. The P(1)-Se(7) bond length is 2.27 Å. Both P(1)-Se(4) bond lengths are 2.17 Å. In the second P site, P(2) is bonded to one Ru(1), one P(2), one Se(3), and one Se(6) atom to form distorted PPRuSe2 tetrahedra that share  a cornercorner with one Ru(1)P3Se3 octahedra and corners with two equivalent P(2)PRuSe2 tetrahedra. The corner-sharing octahedral tilt angles are 63°. The P(2)-P(2) bond length is 2.24 Å. The P(2)-Se(3) bond length is 2.35 Å. The P(2)-Se(6) bond length is 2.27 Å. In the third P site, P(3) is bonded in a 3-coordinate geometry to one K(2), one Se(2), and two equivalent Se(5) atoms. The P(3)-Se(2) bond length is 2.15 Å. Both P(3)-Se(5) bond lengths are 2.24 Å. In the fourth P site, P(4) is bonded in a 4-coordinate geometry to one Ru(1), one Se(1), and two equivalent Se(6) atoms. The P(4)-Se(1) bond length is 2.19 Å. Both P(4)-Se(6) bond lengths are 2.35 Å. There are seven inequivalent Se sites. In the first Se site, Se(1) is bonded in a 5-coordinate geometry to one K(1), three equivalent K(2), and one P(4) atom. In the second Se site, Se(2) is bonded in a 5-coordinate geometry to one K(2), three equivalent K(1), and one P(3) atom. In the third Se site, Se(3) is bonded in a 3-coordinate geometry to one K(2), one K(3), and two equivalent P(2) atoms. In the fourth Se site, Se(4) is bonded in a 5-coordinate geometry to two equivalent K(1), two equivalent K(3), and one P(1) atom. In the fifth Se site, Se(5) is bonded in a 2-coordinate geometry to two equivalent K(2), one Ru(1), and one P(3) atom. In the sixth Se site, Se(6) is bonded in a 3-coordinate geometry to one K(2), one P(2), and one P(4) atom. In the seventh Se site, Se(7) is bonded in a 2-coordinate geometry to one Ru(1) and one P(1) atom.