KYb(BH4)4 crystallizes in the orthorhombic Cmcm space group. K(1) is bonded to two equivalent H(1) and four equivalent H(4) atoms to form distorted KH6 octahedra that share corners with two equivalent B(1)H4 tetrahedra, corners with four equivalent B(2)H4 tetrahedra, and edges with two equivalent K(1)H6 octahedra. Yb(1) is bonded in a 12-coordinate geometry to two equivalent H(2), two equivalent H(5), four equivalent H(3), and four equivalent H(6) atoms. There are two inequivalent B sites. In the first B site, B(1) is bonded to one H(1), one H(2), and two equivalent H(3) atoms to form BH4 tetrahedra that share  a cornercorner with one K(1)H6 octahedra. The corner-sharing octahedral tilt angles are 55°. In the second B site, B(2) is bonded to one H(4), one H(5), and two equivalent H(6) atoms to form BH4 tetrahedra that share corners with two equivalent K(1)H6 octahedra. The corner-sharing octahedral tilt angles are 71°. There are six inequivalent H sites. In the first H site, H(3) is bonded in a single-bond geometry to one Yb(1) and one B(1) atom. In the second H site, H(4) is bonded in a single-bond geometry to two equivalent K(1) and one B(2) atom. In the third H site, H(5) is bonded in a distorted single-bond geometry to one Yb(1) and one B(2) atom. In the fourth H site, H(6) is bonded in a distorted single-bond geometry to one Yb(1) and one B(2) atom. In the fifth H site, H(1) is bonded in a distorted bent 120 degrees geometry to one K(1) and one B(1) atom. In the sixth H site, H(2) is bonded in a distorted L-shaped geometry to one Yb(1) and one B(1) atom.
KYb(BH4)4 crystallizes in the orthorhombic Cmcm space group. K(1) is bonded to two equivalent H(1) and four equivalent H(4) atoms to form distorted KH6 octahedra that share corners with two equivalent B(1)H4 tetrahedra, corners with four equivalent B(2)H4 tetrahedra, and edges with two equivalent K(1)H6 octahedra. Both K(1)-H(1) bond lengths are 2.65 Å. All K(1)-H(4) bond lengths are 2.85 Å. Yb(1) is bonded in a 12-coordinate geometry to two equivalent H(2), two equivalent H(5), four equivalent H(3), and four equivalent H(6) atoms. Both Yb(1)-H(2) bond lengths are 2.27 Å. Both Yb(1)-H(5) bond lengths are 2.36 Å. All Yb(1)-H(3) bond lengths are 2.51 Å. All Yb(1)-H(6) bond lengths are 2.33 Å. There are two inequivalent B sites. In the first B site, B(1) is bonded to one H(1), one H(2), and two equivalent H(3) atoms to form BH4 tetrahedra that share  a cornercorner with one K(1)H6 octahedra. The corner-sharing octahedral tilt angles are 55°. The B(1)-H(1) bond length is 1.21 Å. The B(1)-H(2) bond length is 1.25 Å. Both B(1)-H(3) bond lengths are 1.24 Å. In the second B site, B(2) is bonded to one H(4), one H(5), and two equivalent H(6) atoms to form BH4 tetrahedra that share corners with two equivalent K(1)H6 octahedra. The corner-sharing octahedral tilt angles are 71°. The B(2)-H(4) bond length is 1.22 Å. The B(2)-H(5) bond length is 1.24 Å. Both B(2)-H(6) bond lengths are 1.24 Å. There are six inequivalent H sites. In the first H site, H(3) is bonded in a single-bond geometry to one Yb(1) and one B(1) atom. In the second H site, H(4) is bonded in a single-bond geometry to two equivalent K(1) and one B(2) atom. In the third H site, H(5) is bonded in a distorted single-bond geometry to one Yb(1) and one B(2) atom. In the fourth H site, H(6) is bonded in a distorted single-bond geometry to one Yb(1) and one B(2) atom. In the fifth H site, H(1) is bonded in a distorted bent 120 degrees geometry to one K(1) and one B(1) atom. In the sixth H site, H(2) is bonded in a distorted L-shaped geometry to one Yb(1) and one B(1) atom.