BaBe2Si2O7 crystallizes in the orthorhombic Pmn2_1 space group. Ba(1) is bonded in a 9-coordinate geometry to one O(1), four equivalent O(2), and four equivalent O(3) atoms. Be(1) is bonded to one O(2), one O(3), and two equivalent O(4) atoms to form BeO4 tetrahedra that share corners with two equivalent Be(1)O4 tetrahedra and corners with four equivalent Si(1)O4 tetrahedra. Si(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra and corners with four equivalent Be(1)O4 tetrahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Ba(1) and two equivalent Si(1) atoms. In the second O site, O(2) is bonded in a bent 120 degrees geometry to two equivalent Ba(1), one Be(1), and one Si(1) atom. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to two equivalent Ba(1), one Be(1), and one Si(1) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to two equivalent Be(1) and one Si(1) atom.
BaBe2Si2O7 crystallizes in the orthorhombic Pmn2_1 space group. Ba(1) is bonded in a 9-coordinate geometry to one O(1), four equivalent O(2), and four equivalent O(3) atoms. The Ba(1)-O(1) bond length is 2.85 Å. There are two shorter (2.87 Å) and two longer (3.09 Å) Ba(1)-O(2) bond lengths. There are two shorter (2.77 Å) and two longer (3.12 Å) Ba(1)-O(3) bond lengths. Be(1) is bonded to one O(2), one O(3), and two equivalent O(4) atoms to form BeO4 tetrahedra that share corners with two equivalent Be(1)O4 tetrahedra and corners with four equivalent Si(1)O4 tetrahedra. The Be(1)-O(2) bond length is 1.59 Å. The Be(1)-O(3) bond length is 1.61 Å. There is one shorter (1.67 Å) and one longer (1.68 Å) Be(1)-O(4) bond length. Si(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra and corners with four equivalent Be(1)O4 tetrahedra. The Si(1)-O(1) bond length is 1.66 Å. The Si(1)-O(2) bond length is 1.61 Å. The Si(1)-O(3) bond length is 1.61 Å. The Si(1)-O(4) bond length is 1.63 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Ba(1) and two equivalent Si(1) atoms. In the second O site, O(2) is bonded in a bent 120 degrees geometry to two equivalent Ba(1), one Be(1), and one Si(1) atom. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to two equivalent Ba(1), one Be(1), and one Si(1) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to two equivalent Be(1) and one Si(1) atom.