La5Rh15B4 crystallizes in the tetragonal P4/mmm space group. There are three inequivalent La sites. In the first La site, La(1) is bonded to four equivalent Rh(1), four equivalent Rh(4), and four equivalent Rh(5) atoms to form LaRh12 cuboctahedra that share corners with four equivalent La(2)Rh12 cuboctahedra, corners with eight equivalent La(1)Rh12 cuboctahedra,  a faceface with one La(2)Rh12 cuboctahedra, faces with five equivalent La(1)Rh12 cuboctahedra, and faces with four equivalent B(1)Rh6 octahedra. In the second La site, La(2) is bonded to four equivalent Rh(2), four equivalent Rh(5), and four equivalent Rh(6) atoms to form LaRh12 cuboctahedra that share corners with four equivalent La(1)Rh12 cuboctahedra, corners with four equivalent La(2)Rh12 cuboctahedra, corners with four equivalent La(3)Rh12 cuboctahedra,  a faceface with one La(1)Rh12 cuboctahedra,  a faceface with one La(3)Rh12 cuboctahedra, faces with four equivalent La(2)Rh12 cuboctahedra, faces with four equivalent B(1)Rh6 octahedra, and faces with four equivalent B(2)Rh6 octahedra. In the third La site, La(3) is bonded to four equivalent Rh(3) and eight equivalent Rh(6) atoms to form LaRh12 cuboctahedra that share corners with four equivalent La(3)Rh12 cuboctahedra, corners with eight equivalent La(2)Rh12 cuboctahedra, faces with two equivalent La(2)Rh12 cuboctahedra, faces with four equivalent La(3)Rh12 cuboctahedra, and faces with eight equivalent B(2)Rh6 octahedra. There are six inequivalent Rh sites. In the first Rh site, Rh(1) is bonded in a 1-coordinate geometry to four equivalent La(1) and one B(1) atom. In the second Rh site, Rh(2) is bonded to four equivalent La(2), one B(1), and one B(2) atom to form a mixture of distorted face, corner, and edge-sharing RhLa4B2 octahedra. The corner-sharing octahedral tilt angles range from 0-61°. In the third Rh site, Rh(3) is bonded to four equivalent La(3) and two equivalent B(2) atoms to form a mixture of distorted face, corner, and edge-sharing RhLa4B2 octahedra. The corner-sharing octahedral tilt angles range from 0-60°. In the fourth Rh site, Rh(4) is bonded in a distorted square co-planar geometry to four equivalent La(1) atoms. In the fifth Rh site, Rh(5) is bonded to two equivalent La(1), two equivalent La(2), and two equivalent B(1) atoms to form a mixture of distorted face, corner, and edge-sharing RhLa4B2 octahedra. The corner-sharing octahedral tilt angles range from 0-61°. In the sixth Rh site, Rh(6) is bonded to two equivalent La(2), two equivalent La(3), and two equivalent B(2) atoms to form a mixture of distorted face, corner, and edge-sharing RhLa4B2 octahedra. The corner-sharing octahedral tilt angles range from 0-60°. There are two inequivalent B sites. In the first B site, B(1) is bonded to one Rh(1), one Rh(2), and four equivalent Rh(5) atoms to form BRh6 octahedra that share  a cornercorner with one B(2)Rh6 octahedra, corners with four equivalent B(1)Rh6 octahedra, faces with four equivalent La(1)Rh12 cuboctahedra, and faces with four equivalent La(2)Rh12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-4°. In the second B site, B(2) is bonded to one Rh(2), one Rh(3), and four equivalent Rh(6) atoms to form BRh6 octahedra that share  a cornercorner with one B(1)Rh6 octahedra, corners with five equivalent B(2)Rh6 octahedra, faces with four equivalent La(2)Rh12 cuboctahedra, and faces with four equivalent La(3)Rh12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-1°.
La5Rh15B4 crystallizes in the tetragonal P4/mmm space group. There are three inequivalent La sites. In the first La site, La(1) is bonded to four equivalent Rh(1), four equivalent Rh(4), and four equivalent Rh(5) atoms to form LaRh12 cuboctahedra that share corners with four equivalent La(2)Rh12 cuboctahedra, corners with eight equivalent La(1)Rh12 cuboctahedra,  a faceface with one La(2)Rh12 cuboctahedra, faces with five equivalent La(1)Rh12 cuboctahedra, and faces with four equivalent B(1)Rh6 octahedra. All La(1)-Rh(1) bond lengths are 3.03 Å. All La(1)-Rh(4) bond lengths are 2.95 Å. All La(1)-Rh(5) bond lengths are 3.05 Å. In the second La site, La(2) is bonded to four equivalent Rh(2), four equivalent Rh(5), and four equivalent Rh(6) atoms to form LaRh12 cuboctahedra that share corners with four equivalent La(1)Rh12 cuboctahedra, corners with four equivalent La(2)Rh12 cuboctahedra, corners with four equivalent La(3)Rh12 cuboctahedra,  a faceface with one La(1)Rh12 cuboctahedra,  a faceface with one La(3)Rh12 cuboctahedra, faces with four equivalent La(2)Rh12 cuboctahedra, faces with four equivalent B(1)Rh6 octahedra, and faces with four equivalent B(2)Rh6 octahedra. All La(2)-Rh(2) bond lengths are 3.03 Å. All La(2)-Rh(5) bond lengths are 3.03 Å. All La(2)-Rh(6) bond lengths are 3.01 Å. In the third La site, La(3) is bonded to four equivalent Rh(3) and eight equivalent Rh(6) atoms to form LaRh12 cuboctahedra that share corners with four equivalent La(3)Rh12 cuboctahedra, corners with eight equivalent La(2)Rh12 cuboctahedra, faces with two equivalent La(2)Rh12 cuboctahedra, faces with four equivalent La(3)Rh12 cuboctahedra, and faces with eight equivalent B(2)Rh6 octahedra. All La(3)-Rh(3) bond lengths are 3.03 Å. All La(3)-Rh(6) bond lengths are 3.02 Å. There are six inequivalent Rh sites. In the first Rh site, Rh(1) is bonded in a 1-coordinate geometry to four equivalent La(1) and one B(1) atom. The Rh(1)-B(1) bond length is 2.10 Å. In the second Rh site, Rh(2) is bonded to four equivalent La(2), one B(1), and one B(2) atom to form a mixture of distorted face, corner, and edge-sharing RhLa4B2 octahedra. The corner-sharing octahedral tilt angles range from 0-61°. The Rh(2)-B(1) bond length is 2.18 Å. The Rh(2)-B(2) bond length is 2.14 Å. In the third Rh site, Rh(3) is bonded to four equivalent La(3) and two equivalent B(2) atoms to form a mixture of distorted face, corner, and edge-sharing RhLa4B2 octahedra. The corner-sharing octahedral tilt angles range from 0-60°. Both Rh(3)-B(2) bond lengths are 2.13 Å. In the fourth Rh site, Rh(4) is bonded in a distorted square co-planar geometry to four equivalent La(1) atoms. In the fifth Rh site, Rh(5) is bonded to two equivalent La(1), two equivalent La(2), and two equivalent B(1) atoms to form a mixture of distorted face, corner, and edge-sharing RhLa4B2 octahedra. The corner-sharing octahedral tilt angles range from 0-61°. Both Rh(5)-B(1) bond lengths are 2.15 Å. In the sixth Rh site, Rh(6) is bonded to two equivalent La(2), two equivalent La(3), and two equivalent B(2) atoms to form a mixture of distorted face, corner, and edge-sharing RhLa4B2 octahedra. The corner-sharing octahedral tilt angles range from 0-60°. Both Rh(6)-B(2) bond lengths are 2.14 Å. There are two inequivalent B sites. In the first B site, B(1) is bonded to one Rh(1), one Rh(2), and four equivalent Rh(5) atoms to form BRh6 octahedra that share  a cornercorner with one B(2)Rh6 octahedra, corners with four equivalent B(1)Rh6 octahedra, faces with four equivalent La(1)Rh12 cuboctahedra, and faces with four equivalent La(2)Rh12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-4°. In the second B site, B(2) is bonded to one Rh(2), one Rh(3), and four equivalent Rh(6) atoms to form BRh6 octahedra that share  a cornercorner with one B(1)Rh6 octahedra, corners with five equivalent B(2)Rh6 octahedra, faces with four equivalent La(2)Rh12 cuboctahedra, and faces with four equivalent La(3)Rh12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-1°.