K7NbAs4 crystallizes in the orthorhombic Pmn2_1 space group. There are five inequivalent K sites. In the first K site, K(1) is bonded in a 4-coordinate geometry to one As(1), one As(3), and two equivalent As(2) atoms. In the second K site, K(2) is bonded in a 5-coordinate geometry to one As(1), two equivalent As(2), and two equivalent As(3) atoms. In the third K site, K(3) is bonded in a 4-coordinate geometry to one K(4), one As(1), one As(3), and two equivalent As(2) atoms. In the fourth K site, K(4) is bonded in a 6-coordinate geometry to one K(3), one Nb(1), one As(1), one As(3), and two equivalent As(2) atoms. In the fifth K site, K(5) is bonded in a 3-coordinate geometry to one As(1) and two equivalent As(2) atoms. Nb(1) is bonded in a tetrahedral geometry to one K(4), one As(1), one As(3), and two equivalent As(2) atoms. There are three inequivalent As sites. In the first As site, As(1) is bonded in a 5-coordinate geometry to one K(3), one K(4), one K(5), two equivalent K(1), two equivalent K(2), and one Nb(1) atom. In the second As site, As(2) is bonded in a 8-coordinate geometry to one K(3), one K(4), one K(5), two equivalent K(1), two equivalent K(2), and one Nb(1) atom. In the third As site, As(3) is bonded in a 9-coordinate geometry to one K(3), one K(4), two equivalent K(1), four equivalent K(2), and one Nb(1) atom.
K7NbAs4 crystallizes in the orthorhombic Pmn2_1 space group. There are five inequivalent K sites. In the first K site, K(1) is bonded in a 4-coordinate geometry to one As(1), one As(3), and two equivalent As(2) atoms. The K(1)-As(1) bond length is 3.23 Å. The K(1)-As(3) bond length is 3.34 Å. There is one shorter (3.33 Å) and one longer (3.40 Å) K(1)-As(2) bond length. In the second K site, K(2) is bonded in a 5-coordinate geometry to one As(1), two equivalent As(2), and two equivalent As(3) atoms. The K(2)-As(1) bond length is 3.74 Å. There is one shorter (3.44 Å) and one longer (3.73 Å) K(2)-As(2) bond length. Both K(2)-As(3) bond lengths are 3.46 Å. In the third K site, K(3) is bonded in a 4-coordinate geometry to one K(4), one As(1), one As(3), and two equivalent As(2) atoms. The K(3)-K(4) bond length is 3.27 Å. The K(3)-As(1) bond length is 3.17 Å. The K(3)-As(3) bond length is 3.53 Å. Both K(3)-As(2) bond lengths are 3.38 Å. In the fourth K site, K(4) is bonded in a 6-coordinate geometry to one K(3), one Nb(1), one As(1), one As(3), and two equivalent As(2) atoms. The K(4)-Nb(1) bond length is 3.49 Å. The K(4)-As(1) bond length is 3.56 Å. The K(4)-As(3) bond length is 3.81 Å. Both K(4)-As(2) bond lengths are 3.49 Å. In the fifth K site, K(5) is bonded in a 3-coordinate geometry to one As(1) and two equivalent As(2) atoms. The K(5)-As(1) bond length is 3.24 Å. Both K(5)-As(2) bond lengths are 3.35 Å. Nb(1) is bonded in a tetrahedral geometry to one K(4), one As(1), one As(3), and two equivalent As(2) atoms. The Nb(1)-As(1) bond length is 2.49 Å. The Nb(1)-As(3) bond length is 2.51 Å. Both Nb(1)-As(2) bond lengths are 2.55 Å. There are three inequivalent As sites. In the first As site, As(1) is bonded in a 5-coordinate geometry to one K(3), one K(4), one K(5), two equivalent K(1), two equivalent K(2), and one Nb(1) atom. In the second As site, As(2) is bonded in a 8-coordinate geometry to one K(3), one K(4), one K(5), two equivalent K(1), two equivalent K(2), and one Nb(1) atom. In the third As site, As(3) is bonded in a 9-coordinate geometry to one K(3), one K(4), two equivalent K(1), four equivalent K(2), and one Nb(1) atom.