Yb3H8 crystallizes in the monoclinic C2/m space group. There are four inequivalent Yb sites. In the first Yb site, Yb(1) is bonded in a 14-coordinate geometry to two equivalent H(1), two equivalent H(6), two equivalent H(8), four equivalent H(5), and four equivalent H(7) atoms. In the second Yb site, Yb(2) is bonded in a 14-coordinate geometry to two equivalent H(2), two equivalent H(6), two equivalent H(8), four equivalent H(5), and four equivalent H(7) atoms. In the third Yb site, Yb(3) is bonded in a 7-coordinate geometry to one H(1), one H(4), two equivalent H(2), and three equivalent H(3) atoms. In the fourth Yb site, Yb(4) is bonded in a body-centered cubic geometry to one H(1), one H(6), two equivalent H(2), two equivalent H(3), and two equivalent H(4) atoms. There are eight inequivalent H sites. In the first H site, H(6) is bonded to one Yb(1), one Yb(4), and two equivalent Yb(2) atoms to form a mixture of corner and edge-sharing HYb4 tetrahedra. In the second H site, H(7) is bonded in a single-bond geometry to one Yb(1), two equivalent Yb(2), and one H(5) atom. In the third H site, H(8) is bonded in a 3-coordinate geometry to one Yb(1) and two equivalent Yb(2) atoms. In the fourth H site, H(1) is bonded to one Yb(1), one Yb(4), and two equivalent Yb(3) atoms to form a mixture of corner and edge-sharing HYb4 tetrahedra. In the fifth H site, H(2) is bonded to one Yb(2), one Yb(4), and two equivalent Yb(3) atoms to form a mixture of corner and edge-sharing HYb4 tetrahedra. In the sixth H site, H(3) is bonded to one Yb(4) and three equivalent Yb(3) atoms to form a mixture of corner and edge-sharing HYb4 tetrahedra. In the seventh H site, H(4) is bonded to two equivalent Yb(3) and two equivalent Yb(4) atoms to form a mixture of corner and edge-sharing HYb4 tetrahedra. In the eighth H site, H(5) is bonded in a distorted single-bond geometry to one Yb(1), two equivalent Yb(2), and one H(7) atom.
Yb3H8 crystallizes in the monoclinic C2/m space group. There are four inequivalent Yb sites. In the first Yb site, Yb(1) is bonded in a 14-coordinate geometry to two equivalent H(1), two equivalent H(6), two equivalent H(8), four equivalent H(5), and four equivalent H(7) atoms. Both Yb(1)-H(1) bond lengths are 2.34 Å. Both Yb(1)-H(6) bond lengths are 2.25 Å. Both Yb(1)-H(8) bond lengths are 2.42 Å. All Yb(1)-H(5) bond lengths are 2.24 Å. All Yb(1)-H(7) bond lengths are 2.26 Å. In the second Yb site, Yb(2) is bonded in a 14-coordinate geometry to two equivalent H(2), two equivalent H(6), two equivalent H(8), four equivalent H(5), and four equivalent H(7) atoms. Both Yb(2)-H(2) bond lengths are 2.30 Å. Both Yb(2)-H(6) bond lengths are 2.19 Å. Both Yb(2)-H(8) bond lengths are 2.35 Å. There are two shorter (2.33 Å) and two longer (2.46 Å) Yb(2)-H(5) bond lengths. There are two shorter (2.36 Å) and two longer (2.48 Å) Yb(2)-H(7) bond lengths. In the third Yb site, Yb(3) is bonded in a 7-coordinate geometry to one H(1), one H(4), two equivalent H(2), and three equivalent H(3) atoms. The Yb(3)-H(1) bond length is 2.34 Å. The Yb(3)-H(4) bond length is 2.29 Å. There is one shorter (2.34 Å) and one longer (2.38 Å) Yb(3)-H(2) bond length. There are a spread of Yb(3)-H(3) bond distances ranging from 2.30-2.38 Å. In the fourth Yb site, Yb(4) is bonded in a body-centered cubic geometry to one H(1), one H(6), two equivalent H(2), two equivalent H(3), and two equivalent H(4) atoms. The Yb(4)-H(1) bond length is 2.31 Å. The Yb(4)-H(6) bond length is 2.20 Å. Both Yb(4)-H(2) bond lengths are 2.41 Å. Both Yb(4)-H(3) bond lengths are 2.37 Å. There is one shorter (2.32 Å) and one longer (2.34 Å) Yb(4)-H(4) bond length. There are eight inequivalent H sites. In the first H site, H(6) is bonded to one Yb(1), one Yb(4), and two equivalent Yb(2) atoms to form a mixture of corner and edge-sharing HYb4 tetrahedra. In the second H site, H(7) is bonded in a single-bond geometry to one Yb(1), two equivalent Yb(2), and one H(5) atom. The H(7)-H(5) bond length is 0.86 Å. In the third H site, H(8) is bonded in a 3-coordinate geometry to one Yb(1) and two equivalent Yb(2) atoms. In the fourth H site, H(1) is bonded to one Yb(1), one Yb(4), and two equivalent Yb(3) atoms to form a mixture of corner and edge-sharing HYb4 tetrahedra. In the fifth H site, H(2) is bonded to one Yb(2), one Yb(4), and two equivalent Yb(3) atoms to form a mixture of corner and edge-sharing HYb4 tetrahedra. In the sixth H site, H(3) is bonded to one Yb(4) and three equivalent Yb(3) atoms to form a mixture of corner and edge-sharing HYb4 tetrahedra. In the seventh H site, H(4) is bonded to two equivalent Yb(3) and two equivalent Yb(4) atoms to form a mixture of corner and edge-sharing HYb4 tetrahedra. In the eighth H site, H(5) is bonded in a distorted single-bond geometry to one Yb(1), two equivalent Yb(2), and one H(7) atom.