K2Mo4O13 crystallizes in the triclinic P-1 space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 3-coordinate geometry to one O(11), one O(7), and two equivalent O(6) atoms. In the second K site, K(2) is bonded in a 7-coordinate geometry to one O(1), one O(10), one O(11), one O(13), one O(9), and two equivalent O(3) atoms. There are four inequivalent Mo sites. In the first Mo site, Mo(1) is bonded in a 3-coordinate geometry to one O(12), one O(5), one O(8), and one O(9) atom. In the second Mo site, Mo(2) is bonded in a 2-coordinate geometry to one O(1), one O(13), one O(2), and one O(4) atom. In the third Mo site, Mo(3) is bonded in a 3-coordinate geometry to one O(11), one O(2), one O(3), and one O(7) atom. In the fourth Mo site, Mo(4) is bonded in a 2-coordinate geometry to one O(10), one O(12), one O(6), and one O(7) atom. There are thirteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one K(2) and one Mo(2) atom. In the second O site, O(2) is bonded in a water-like geometry to one Mo(2) and one Mo(3) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to two equivalent K(2) and one Mo(3) atom. In the fourth O site, O(4) is bonded in a single-bond geometry to one Mo(2) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to one Mo(1) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to two equivalent K(1) and one Mo(4) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one K(1), one Mo(3), and one Mo(4) atom. In the eighth O site, O(8) is bonded in a single-bond geometry to one Mo(1) atom. In the ninth O site, O(9) is bonded in a distorted bent 150 degrees geometry to one K(2) and one Mo(1) atom. In the tenth O site, O(10) is bonded in a single-bond geometry to one K(2) and one Mo(4) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one K(1), one K(2), and one Mo(3) atom. In the twelfth O site, O(12) is bonded in an L-shaped geometry to one Mo(1) and one Mo(4) atom. In the thirteenth O site, O(13) is bonded in a water-like geometry to one K(2) and one Mo(2) atom.
K2Mo4O13 crystallizes in the triclinic P-1 space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 3-coordinate geometry to one O(11), one O(7), and two equivalent O(6) atoms. The K(1)-O(11) bond length is 2.62 Å. The K(1)-O(7) bond length is 2.24 Å. There is one shorter (2.35 Å) and one longer (3.16 Å) K(1)-O(6) bond length. In the second K site, K(2) is bonded in a 7-coordinate geometry to one O(1), one O(10), one O(11), one O(13), one O(9), and two equivalent O(3) atoms. The K(2)-O(1) bond length is 3.13 Å. The K(2)-O(10) bond length is 3.11 Å. The K(2)-O(11) bond length is 2.94 Å. The K(2)-O(13) bond length is 2.85 Å. The K(2)-O(9) bond length is 2.53 Å. There is one shorter (2.53 Å) and one longer (3.29 Å) K(2)-O(3) bond length. There are four inequivalent Mo sites. In the first Mo site, Mo(1) is bonded in a 3-coordinate geometry to one O(12), one O(5), one O(8), and one O(9) atom. The Mo(1)-O(12) bond length is 1.89 Å. The Mo(1)-O(5) bond length is 2.72 Å. The Mo(1)-O(8) bond length is 1.40 Å. The Mo(1)-O(9) bond length is 1.45 Å. In the second Mo site, Mo(2) is bonded in a 2-coordinate geometry to one O(1), one O(13), one O(2), and one O(4) atom. The Mo(2)-O(1) bond length is 1.89 Å. The Mo(2)-O(13) bond length is 2.84 Å. The Mo(2)-O(2) bond length is 1.47 Å. The Mo(2)-O(4) bond length is 1.50 Å. In the third Mo site, Mo(3) is bonded in a 3-coordinate geometry to one O(11), one O(2), one O(3), and one O(7) atom. The Mo(3)-O(11) bond length is 1.74 Å. The Mo(3)-O(2) bond length is 1.49 Å. The Mo(3)-O(3) bond length is 2.67 Å. The Mo(3)-O(7) bond length is 1.42 Å. In the fourth Mo site, Mo(4) is bonded in a 2-coordinate geometry to one O(10), one O(12), one O(6), and one O(7) atom. The Mo(4)-O(10) bond length is 1.19 Å. The Mo(4)-O(12) bond length is 1.64 Å. The Mo(4)-O(6) bond length is 2.75 Å. The Mo(4)-O(7) bond length is 2.10 Å. There are thirteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one K(2) and one Mo(2) atom. In the second O site, O(2) is bonded in a water-like geometry to one Mo(2) and one Mo(3) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to two equivalent K(2) and one Mo(3) atom. In the fourth O site, O(4) is bonded in a single-bond geometry to one Mo(2) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to one Mo(1) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to two equivalent K(1) and one Mo(4) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one K(1), one Mo(3), and one Mo(4) atom. In the eighth O site, O(8) is bonded in a single-bond geometry to one Mo(1) atom. In the ninth O site, O(9) is bonded in a distorted bent 150 degrees geometry to one K(2) and one Mo(1) atom. In the tenth O site, O(10) is bonded in a single-bond geometry to one K(2) and one Mo(4) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one K(1), one K(2), and one Mo(3) atom. In the twelfth O site, O(12) is bonded in an L-shaped geometry to one Mo(1) and one Mo(4) atom. In the thirteenth O site, O(13) is bonded in a water-like geometry to one K(2) and one Mo(2) atom.