Ba2YBr7 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to one Br(1), two equivalent Br(2), two equivalent Br(3), and two equivalent Br(4) atoms to form distorted BaBr7 pentagonal bipyramids that share corners with two equivalent Y(1)Br6 pentagonal pyramids, edges with two equivalent Ba(2)Br7 pentagonal bipyramids, edges with two equivalent Y(1)Br6 pentagonal pyramids, and  a faceface with one Ba(2)Br7 pentagonal bipyramid. In the second Ba site, Ba(2) is bonded to one Br(1), two equivalent Br(2), two equivalent Br(3), and two equivalent Br(4) atoms to form distorted BaBr7 pentagonal bipyramids that share corners with two equivalent Y(1)Br6 pentagonal pyramids, edges with two equivalent Ba(1)Br7 pentagonal bipyramids, edges with two equivalent Y(1)Br6 pentagonal pyramids, and  a faceface with one Ba(1)Br7 pentagonal bipyramid. Y(1) is bonded to two equivalent Br(2), two equivalent Br(3), and two equivalent Br(4) atoms to form distorted YBr6 pentagonal pyramids that share corners with two equivalent Ba(1)Br7 pentagonal bipyramids, corners with two equivalent Ba(2)Br7 pentagonal bipyramids, edges with two equivalent Ba(1)Br7 pentagonal bipyramids, and edges with two equivalent Ba(2)Br7 pentagonal bipyramids. There are four inequivalent Br sites. In the first Br site, Br(1) is bonded in an L-shaped geometry to one Ba(1) and one Ba(2) atom. In the second Br site, Br(2) is bonded in a distorted trigonal non-coplanar geometry to one Ba(1), one Ba(2), and one Y(1) atom. In the third Br site, Br(3) is bonded in a trigonal non-coplanar geometry to one Ba(1), one Ba(2), and one Y(1) atom. In the fourth Br site, Br(4) is bonded in a distorted T-shaped geometry to one Ba(1), one Ba(2), and one Y(1) atom.
Ba2YBr7 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to one Br(1), two equivalent Br(2), two equivalent Br(3), and two equivalent Br(4) atoms to form distorted BaBr7 pentagonal bipyramids that share corners with two equivalent Y(1)Br6 pentagonal pyramids, edges with two equivalent Ba(2)Br7 pentagonal bipyramids, edges with two equivalent Y(1)Br6 pentagonal pyramids, and  a faceface with one Ba(2)Br7 pentagonal bipyramid. The Ba(1)-Br(1) bond length is 3.10 Å. Both Ba(1)-Br(2) bond lengths are 3.35 Å. Both Ba(1)-Br(3) bond lengths are 3.29 Å. Both Ba(1)-Br(4) bond lengths are 3.37 Å. In the second Ba site, Ba(2) is bonded to one Br(1), two equivalent Br(2), two equivalent Br(3), and two equivalent Br(4) atoms to form distorted BaBr7 pentagonal bipyramids that share corners with two equivalent Y(1)Br6 pentagonal pyramids, edges with two equivalent Ba(1)Br7 pentagonal bipyramids, edges with two equivalent Y(1)Br6 pentagonal pyramids, and  a faceface with one Ba(1)Br7 pentagonal bipyramid. The Ba(2)-Br(1) bond length is 3.07 Å. Both Ba(2)-Br(2) bond lengths are 3.38 Å. Both Ba(2)-Br(3) bond lengths are 3.34 Å. Both Ba(2)-Br(4) bond lengths are 3.37 Å. Y(1) is bonded to two equivalent Br(2), two equivalent Br(3), and two equivalent Br(4) atoms to form distorted YBr6 pentagonal pyramids that share corners with two equivalent Ba(1)Br7 pentagonal bipyramids, corners with two equivalent Ba(2)Br7 pentagonal bipyramids, edges with two equivalent Ba(1)Br7 pentagonal bipyramids, and edges with two equivalent Ba(2)Br7 pentagonal bipyramids. Both Y(1)-Br(2) bond lengths are 2.88 Å. Both Y(1)-Br(3) bond lengths are 2.85 Å. Both Y(1)-Br(4) bond lengths are 2.80 Å. There are four inequivalent Br sites. In the first Br site, Br(1) is bonded in an L-shaped geometry to one Ba(1) and one Ba(2) atom. In the second Br site, Br(2) is bonded in a distorted trigonal non-coplanar geometry to one Ba(1), one Ba(2), and one Y(1) atom. In the third Br site, Br(3) is bonded in a trigonal non-coplanar geometry to one Ba(1), one Ba(2), and one Y(1) atom. In the fourth Br site, Br(4) is bonded in a distorted T-shaped geometry to one Ba(1), one Ba(2), and one Y(1) atom.