K5BaNbAs4 crystallizes in the monoclinic Cc space group. There are five inequivalent K sites. In the first K site, K(1) is bonded in a 5-coordinate geometry to one As(1), two equivalent As(3), and two equivalent As(4) atoms. In the second K site, K(2) is bonded in a 5-coordinate geometry to one As(1), one As(3), one As(4), and two equivalent As(2) atoms. In the third K site, K(3) is bonded in a 4-coordinate geometry to one As(1), one As(2), one As(3), and one As(4) atom. In the fourth K site, K(4) is bonded in a 4-coordinate geometry to one As(1), one As(2), and two equivalent As(4) atoms. In the fifth K site, K(5) is bonded in a 4-coordinate geometry to one As(1), one As(2), and two equivalent As(3) atoms. Ba(1) is bonded in a 5-coordinate geometry to one As(1), one As(3), one As(4), and two equivalent As(2) atoms. Nb(1) is bonded in a tetrahedral geometry to one As(1), one As(2), one As(3), and one As(4) atom. There are four inequivalent As sites. In the first As site, As(4) is bonded in a 8-coordinate geometry to one K(2), one K(3), two equivalent K(1), two equivalent K(4), one Ba(1), and one Nb(1) atom. In the second As site, As(1) is bonded in a 7-coordinate geometry to one K(1), one K(2), one K(3), one K(4), one K(5), one Ba(1), and one Nb(1) atom. In the third As site, As(2) is bonded in a 8-coordinate geometry to one K(3), one K(4), one K(5), two equivalent K(2), two equivalent Ba(1), and one Nb(1) atom. In the fourth As site, As(3) is bonded in a 8-coordinate geometry to one K(2), one K(3), two equivalent K(1), two equivalent K(5), one Ba(1), and one Nb(1) atom.
K5BaNbAs4 crystallizes in the monoclinic Cc space group. There are five inequivalent K sites. In the first K site, K(1) is bonded in a 5-coordinate geometry to one As(1), two equivalent As(3), and two equivalent As(4) atoms. The K(1)-As(1) bond length is 3.57 Å. There is one shorter (3.45 Å) and one longer (3.67 Å) K(1)-As(3) bond length. There is one shorter (3.48 Å) and one longer (3.59 Å) K(1)-As(4) bond length. In the second K site, K(2) is bonded in a 5-coordinate geometry to one As(1), one As(3), one As(4), and two equivalent As(2) atoms. The K(2)-As(1) bond length is 3.46 Å. The K(2)-As(3) bond length is 3.62 Å. The K(2)-As(4) bond length is 3.44 Å. There is one shorter (3.44 Å) and one longer (3.60 Å) K(2)-As(2) bond length. In the third K site, K(3) is bonded in a 4-coordinate geometry to one As(1), one As(2), one As(3), and one As(4) atom. The K(3)-As(1) bond length is 3.45 Å. The K(3)-As(2) bond length is 3.38 Å. The K(3)-As(3) bond length is 3.36 Å. The K(3)-As(4) bond length is 3.32 Å. In the fourth K site, K(4) is bonded in a 4-coordinate geometry to one As(1), one As(2), and two equivalent As(4) atoms. The K(4)-As(1) bond length is 3.52 Å. The K(4)-As(2) bond length is 3.46 Å. There is one shorter (3.32 Å) and one longer (3.38 Å) K(4)-As(4) bond length. In the fifth K site, K(5) is bonded in a 4-coordinate geometry to one As(1), one As(2), and two equivalent As(3) atoms. The K(5)-As(1) bond length is 3.46 Å. The K(5)-As(2) bond length is 3.45 Å. There is one shorter (3.38 Å) and one longer (3.42 Å) K(5)-As(3) bond length. Ba(1) is bonded in a 5-coordinate geometry to one As(1), one As(3), one As(4), and two equivalent As(2) atoms. The Ba(1)-As(1) bond length is 3.42 Å. The Ba(1)-As(3) bond length is 3.34 Å. The Ba(1)-As(4) bond length is 3.48 Å. There is one shorter (3.37 Å) and one longer (3.55 Å) Ba(1)-As(2) bond length. Nb(1) is bonded in a tetrahedral geometry to one As(1), one As(2), one As(3), and one As(4) atom. The Nb(1)-As(1) bond length is 2.52 Å. The Nb(1)-As(2) bond length is 2.54 Å. The Nb(1)-As(3) bond length is 2.51 Å. The Nb(1)-As(4) bond length is 2.52 Å. There are four inequivalent As sites. In the first As site, As(4) is bonded in a 8-coordinate geometry to one K(2), one K(3), two equivalent K(1), two equivalent K(4), one Ba(1), and one Nb(1) atom. In the second As site, As(1) is bonded in a 7-coordinate geometry to one K(1), one K(2), one K(3), one K(4), one K(5), one Ba(1), and one Nb(1) atom. In the third As site, As(2) is bonded in a 8-coordinate geometry to one K(3), one K(4), one K(5), two equivalent K(2), two equivalent Ba(1), and one Nb(1) atom. In the fourth As site, As(3) is bonded in a 8-coordinate geometry to one K(2), one K(3), two equivalent K(1), two equivalent K(5), one Ba(1), and one Nb(1) atom.