BaYbAl2SiN5O2 crystallizes in the monoclinic Cc space group. Ba(1) is bonded in a 8-coordinate geometry to one N(4), one N(5), two equivalent N(2), two equivalent N(3), one O(1), and one O(2) atom. Yb(1) is bonded to one N(2), one N(3), one N(4), one O(1), and one O(2) atom to form distorted YbN3O2 square pyramids that share  a cornercorner with one Al(1)N3O tetrahedra, corners with three equivalent Si(1)N3O tetrahedra, and  an edgeedge with one Al(1)N3O tetrahedra. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one N(1), one N(3), one N(4), and one O(1) atom to form distorted AlN3O tetrahedra that share  a cornercorner with one Yb(1)N3O2 square pyramid, corners with two equivalent Si(1)N3O tetrahedra, and  an edgeedge with one Yb(1)N3O2 square pyramid. In the second Al site, Al(2) is bonded in a 4-coordinate geometry to one N(1), one N(2), one N(4), and one O(2) atom. Si(1) is bonded to one N(1), one N(2), one N(3), and one O(2) atom to form distorted SiN3O tetrahedra that share corners with three equivalent Yb(1)N3O2 square pyramids and corners with two equivalent Al(1)N3O tetrahedra. There are five inequivalent N sites. In the first N site, N(1) is bonded in a distorted tetrahedral geometry to one Al(1), one Al(2), one Si(1), and one N(5) atom. In the second N site, N(2) is bonded in a 5-coordinate geometry to two equivalent Ba(1), one Yb(1), one Al(2), and one Si(1) atom. In the third N site, N(3) is bonded in a 4-coordinate geometry to two equivalent Ba(1), one Yb(1), one Al(1), and one Si(1) atom. In the fourth N site, N(4) is bonded in a 4-coordinate geometry to one Ba(1), one Yb(1), one Al(1), and one Al(2) atom. In the fifth N site, N(5) is bonded in a 1-coordinate geometry to one Ba(1), one N(1), and one O(1) atom. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Ba(1), one Yb(1), one Al(1), and one N(5) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Ba(1), one Yb(1), one Al(2), and one Si(1) atom.
BaYbAl2SiN5O2 crystallizes in the monoclinic Cc space group. Ba(1) is bonded in a 8-coordinate geometry to one N(4), one N(5), two equivalent N(2), two equivalent N(3), one O(1), and one O(2) atom. The Ba(1)-N(4) bond length is 2.65 Å. The Ba(1)-N(5) bond length is 3.22 Å. There is one shorter (2.79 Å) and one longer (2.83 Å) Ba(1)-N(2) bond length. There is one shorter (2.60 Å) and one longer (3.14 Å) Ba(1)-N(3) bond length. The Ba(1)-O(1) bond length is 2.87 Å. The Ba(1)-O(2) bond length is 2.87 Å. Yb(1) is bonded to one N(2), one N(3), one N(4), one O(1), and one O(2) atom to form distorted YbN3O2 square pyramids that share  a cornercorner with one Al(1)N3O tetrahedra, corners with three equivalent Si(1)N3O tetrahedra, and  an edgeedge with one Al(1)N3O tetrahedra. The Yb(1)-N(2) bond length is 2.40 Å. The Yb(1)-N(3) bond length is 2.50 Å. The Yb(1)-N(4) bond length is 2.34 Å. The Yb(1)-O(1) bond length is 2.51 Å. The Yb(1)-O(2) bond length is 2.40 Å. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one N(1), one N(3), one N(4), and one O(1) atom to form distorted AlN3O tetrahedra that share  a cornercorner with one Yb(1)N3O2 square pyramid, corners with two equivalent Si(1)N3O tetrahedra, and  an edgeedge with one Yb(1)N3O2 square pyramid. The Al(1)-N(1) bond length is 2.02 Å. The Al(1)-N(3) bond length is 1.86 Å. The Al(1)-N(4) bond length is 1.79 Å. The Al(1)-O(1) bond length is 1.93 Å. In the second Al site, Al(2) is bonded in a 4-coordinate geometry to one N(1), one N(2), one N(4), and one O(2) atom. The Al(2)-N(1) bond length is 2.05 Å. The Al(2)-N(2) bond length is 1.91 Å. The Al(2)-N(4) bond length is 1.83 Å. The Al(2)-O(2) bond length is 1.94 Å. Si(1) is bonded to one N(1), one N(2), one N(3), and one O(2) atom to form distorted SiN3O tetrahedra that share corners with three equivalent Yb(1)N3O2 square pyramids and corners with two equivalent Al(1)N3O tetrahedra. The Si(1)-N(1) bond length is 2.03 Å. The Si(1)-N(2) bond length is 1.73 Å. The Si(1)-N(3) bond length is 1.70 Å. The Si(1)-O(2) bond length is 1.70 Å. There are five inequivalent N sites. In the first N site, N(1) is bonded in a distorted tetrahedral geometry to one Al(1), one Al(2), one Si(1), and one N(5) atom. The N(1)-N(5) bond length is 1.41 Å. In the second N site, N(2) is bonded in a 5-coordinate geometry to two equivalent Ba(1), one Yb(1), one Al(2), and one Si(1) atom. In the third N site, N(3) is bonded in a 4-coordinate geometry to two equivalent Ba(1), one Yb(1), one Al(1), and one Si(1) atom. In the fourth N site, N(4) is bonded in a 4-coordinate geometry to one Ba(1), one Yb(1), one Al(1), and one Al(2) atom. In the fifth N site, N(5) is bonded in a 1-coordinate geometry to one Ba(1), one N(1), and one O(1) atom. The N(5)-O(1) bond length is 1.39 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Ba(1), one Yb(1), one Al(1), and one N(5) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Ba(1), one Yb(1), one Al(2), and one Si(1) atom.