Ba7Hg31 crystallizes in the hexagonal P-6m2 space group. There are four inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 20-coordinate geometry to two equivalent Hg(3), six equivalent Hg(1), six equivalent Hg(2), and six equivalent Hg(5) atoms. In the second Ba site, Ba(2) is bonded in a 8-coordinate geometry to two equivalent Hg(4), six equivalent Hg(1), and six equivalent Hg(2) atoms. In the third Ba site, Ba(3) is bonded in a 16-coordinate geometry to two equivalent Hg(2), two equivalent Hg(3), two equivalent Hg(4), two equivalent Hg(7), four equivalent Hg(5), and four equivalent Hg(6) atoms. In the fourth Ba site, Ba(4) is bonded in a 15-coordinate geometry to three equivalent Hg(5), three equivalent Hg(6), three equivalent Hg(7), and six equivalent Hg(1) atoms. There are seven inequivalent Hg sites. In the first Hg site, Hg(7) is bonded in a 8-coordinate geometry to two equivalent Ba(3), two equivalent Ba(4), two equivalent Hg(5), and two equivalent Hg(7) atoms. In the second Hg site, Hg(1) is bonded in a 10-coordinate geometry to one Ba(1), one Ba(2), two equivalent Ba(4), two equivalent Hg(1), two equivalent Hg(2), and two equivalent Hg(5) atoms. In the third Hg site, Hg(2) is bonded in a 9-coordinate geometry to one Ba(1), one Ba(2), one Ba(3), two equivalent Hg(1), two equivalent Hg(5), and two equivalent Hg(6) atoms. In the fourth Hg site, Hg(3) is bonded in a body-centered cubic geometry to one Ba(1), three equivalent Ba(3), one Hg(3), and three equivalent Hg(5) atoms. In the fifth Hg site, Hg(4) is bonded in a distorted body-centered cubic geometry to one Ba(2), three equivalent Ba(3), one Hg(4), and three equivalent Hg(6) atoms. In the sixth Hg site, Hg(5) is bonded in a 10-coordinate geometry to one Ba(1), one Ba(4), two equivalent Ba(3), one Hg(3), one Hg(7), two equivalent Hg(1), and two equivalent Hg(2) atoms. In the seventh Hg site, Hg(6) is bonded in a 4-coordinate geometry to one Ba(4), two equivalent Ba(3), one Hg(4), and two equivalent Hg(2) atoms.
Ba7Hg31 crystallizes in the hexagonal P-6m2 space group. There are four inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 20-coordinate geometry to two equivalent Hg(3), six equivalent Hg(1), six equivalent Hg(2), and six equivalent Hg(5) atoms. Both Ba(1)-Hg(3) bond lengths are 3.70 Å. All Ba(1)-Hg(1) bond lengths are 4.05 Å. All Ba(1)-Hg(2) bond lengths are 3.67 Å. All Ba(1)-Hg(5) bond lengths are 3.93 Å. In the second Ba site, Ba(2) is bonded in a 8-coordinate geometry to two equivalent Hg(4), six equivalent Hg(1), and six equivalent Hg(2) atoms. Both Ba(2)-Hg(4) bond lengths are 3.67 Å. All Ba(2)-Hg(1) bond lengths are 4.03 Å. All Ba(2)-Hg(2) bond lengths are 3.55 Å. In the third Ba site, Ba(3) is bonded in a 16-coordinate geometry to two equivalent Hg(2), two equivalent Hg(3), two equivalent Hg(4), two equivalent Hg(7), four equivalent Hg(5), and four equivalent Hg(6) atoms. Both Ba(3)-Hg(2) bond lengths are 3.49 Å. Both Ba(3)-Hg(3) bond lengths are 3.52 Å. Both Ba(3)-Hg(4) bond lengths are 3.52 Å. Both Ba(3)-Hg(7) bond lengths are 3.98 Å. All Ba(3)-Hg(5) bond lengths are 3.85 Å. All Ba(3)-Hg(6) bond lengths are 3.69 Å. In the fourth Ba site, Ba(4) is bonded in a 15-coordinate geometry to three equivalent Hg(5), three equivalent Hg(6), three equivalent Hg(7), and six equivalent Hg(1) atoms. All Ba(4)-Hg(5) bond lengths are 3.63 Å. All Ba(4)-Hg(6) bond lengths are 3.56 Å. All Ba(4)-Hg(7) bond lengths are 3.57 Å. All Ba(4)-Hg(1) bond lengths are 3.68 Å. There are seven inequivalent Hg sites. In the first Hg site, Hg(7) is bonded in a 8-coordinate geometry to two equivalent Ba(3), two equivalent Ba(4), two equivalent Hg(5), and two equivalent Hg(7) atoms. Both Hg(7)-Hg(5) bond lengths are 2.97 Å. Both Hg(7)-Hg(7) bond lengths are 3.22 Å. In the second Hg site, Hg(1) is bonded in a 10-coordinate geometry to one Ba(1), one Ba(2), two equivalent Ba(4), two equivalent Hg(1), two equivalent Hg(2), and two equivalent Hg(5) atoms. There is one shorter (2.95 Å) and one longer (3.00 Å) Hg(1)-Hg(1) bond length. Both Hg(1)-Hg(2) bond lengths are 3.05 Å. Both Hg(1)-Hg(5) bond lengths are 3.33 Å. In the third Hg site, Hg(2) is bonded in a 9-coordinate geometry to one Ba(1), one Ba(2), one Ba(3), two equivalent Hg(1), two equivalent Hg(5), and two equivalent Hg(6) atoms. Both Hg(2)-Hg(5) bond lengths are 3.20 Å. Both Hg(2)-Hg(6) bond lengths are 3.32 Å. In the fourth Hg site, Hg(3) is bonded in a body-centered cubic geometry to one Ba(1), three equivalent Ba(3), one Hg(3), and three equivalent Hg(5) atoms. The Hg(3)-Hg(3) bond length is 3.04 Å. All Hg(3)-Hg(5) bond lengths are 2.91 Å. In the fifth Hg site, Hg(4) is bonded in a distorted body-centered cubic geometry to one Ba(2), three equivalent Ba(3), one Hg(4), and three equivalent Hg(6) atoms. The Hg(4)-Hg(4) bond length is 3.11 Å. All Hg(4)-Hg(6) bond lengths are 2.96 Å. In the sixth Hg site, Hg(5) is bonded in a 10-coordinate geometry to one Ba(1), one Ba(4), two equivalent Ba(3), one Hg(3), one Hg(7), two equivalent Hg(1), and two equivalent Hg(2) atoms. In the seventh Hg site, Hg(6) is bonded in a 4-coordinate geometry to one Ba(4), two equivalent Ba(3), one Hg(4), and two equivalent Hg(2) atoms.