NaY(BH4)4 crystallizes in the orthorhombic Cmcm space group. Na(1) is bonded in a 6-coordinate geometry to two equivalent H(1) and four equivalent H(4) atoms. Y(1) is bonded to two equivalent H(2), two equivalent H(5), four equivalent H(3), and four equivalent H(6) atoms to form distorted YH12 cuboctahedra that share faces with two equivalent B(1)H4 tetrahedra and faces with two equivalent B(2)H4 tetrahedra. There are two inequivalent B sites. In the first B site, B(1) is bonded to one H(1), one H(2), and two equivalent H(3) atoms to form BH4 tetrahedra that share  a faceface with one Y(1)H12 cuboctahedra. In the second B site, B(2) is bonded to one H(4), one H(5), and two equivalent H(6) atoms to form BH4 tetrahedra that share  a faceface with one Y(1)H12 cuboctahedra. There are six inequivalent H sites. In the first H site, H(3) is bonded in a distorted single-bond geometry to one Y(1) and one B(1) atom. In the second H site, H(4) is bonded in a single-bond geometry to two equivalent Na(1) and one B(2) atom. In the third H site, H(5) is bonded in a distorted single-bond geometry to one Y(1) and one B(2) atom. In the fourth H site, H(6) is bonded in a distorted single-bond geometry to one Y(1) and one B(2) atom. In the fifth H site, H(1) is bonded in a distorted water-like geometry to one Na(1) and one B(1) atom. In the sixth H site, H(2) is bonded in a distorted single-bond geometry to one Y(1) and one B(1) atom.
NaY(BH4)4 crystallizes in the orthorhombic Cmcm space group. Na(1) is bonded in a 6-coordinate geometry to two equivalent H(1) and four equivalent H(4) atoms. Both Na(1)-H(1) bond lengths are 2.39 Å. All Na(1)-H(4) bond lengths are 2.63 Å. Y(1) is bonded to two equivalent H(2), two equivalent H(5), four equivalent H(3), and four equivalent H(6) atoms to form distorted YH12 cuboctahedra that share faces with two equivalent B(1)H4 tetrahedra and faces with two equivalent B(2)H4 tetrahedra. Both Y(1)-H(2) bond lengths are 2.34 Å. Both Y(1)-H(5) bond lengths are 2.32 Å. All Y(1)-H(3) bond lengths are 2.31 Å. All Y(1)-H(6) bond lengths are 2.36 Å. There are two inequivalent B sites. In the first B site, B(1) is bonded to one H(1), one H(2), and two equivalent H(3) atoms to form BH4 tetrahedra that share  a faceface with one Y(1)H12 cuboctahedra. The B(1)-H(1) bond length is 1.20 Å. The B(1)-H(2) bond length is 1.24 Å. Both B(1)-H(3) bond lengths are 1.24 Å. In the second B site, B(2) is bonded to one H(4), one H(5), and two equivalent H(6) atoms to form BH4 tetrahedra that share  a faceface with one Y(1)H12 cuboctahedra. The B(2)-H(4) bond length is 1.21 Å. The B(2)-H(5) bond length is 1.23 Å. Both B(2)-H(6) bond lengths are 1.24 Å. There are six inequivalent H sites. In the first H site, H(3) is bonded in a distorted single-bond geometry to one Y(1) and one B(1) atom. In the second H site, H(4) is bonded in a single-bond geometry to two equivalent Na(1) and one B(2) atom. In the third H site, H(5) is bonded in a distorted single-bond geometry to one Y(1) and one B(2) atom. In the fourth H site, H(6) is bonded in a distorted single-bond geometry to one Y(1) and one B(2) atom. In the fifth H site, H(1) is bonded in a distorted water-like geometry to one Na(1) and one B(1) atom. In the sixth H site, H(2) is bonded in a distorted single-bond geometry to one Y(1) and one B(1) atom.