Be2Yb2SiO7 crystallizes in the tetragonal P-42_1m space group. Be(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form BeO4 tetrahedra that share  a cornercorner with one Be(1)O4 tetrahedra and corners with two equivalent Si(1)O4 tetrahedra. Yb(1) is bonded in a 8-coordinate geometry to one O(1), three equivalent O(2), and four equivalent O(3) atoms. Si(1) is bonded to four equivalent O(3) atoms to form SiO4 tetrahedra that share corners with four equivalent Be(1)O4 tetrahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Be(1) and two equivalent Yb(1) atoms to form a mixture of distorted corner and edge-sharing OYb2Be2 tetrahedra. In the second O site, O(2) is bonded to one Be(1) and three equivalent Yb(1) atoms to form distorted OYb3Be tetrahedra that share corners with two equivalent O(1)Yb2Be2 tetrahedra, corners with four equivalent O(2)Yb3Be tetrahedra,  an edgeedge with one O(1)Yb2Be2 tetrahedra, and  an edgeedge with one O(2)Yb3Be tetrahedra. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Be(1), two equivalent Yb(1), and one Si(1) atom.
Be2Yb2SiO7 crystallizes in the tetragonal P-42_1m space group. Be(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form BeO4 tetrahedra that share  a cornercorner with one Be(1)O4 tetrahedra and corners with two equivalent Si(1)O4 tetrahedra. The Be(1)-O(1) bond length is 1.57 Å. The Be(1)-O(2) bond length is 1.61 Å. Both Be(1)-O(3) bond lengths are 1.66 Å. Yb(1) is bonded in a 8-coordinate geometry to one O(1), three equivalent O(2), and four equivalent O(3) atoms. The Yb(1)-O(1) bond length is 2.30 Å. There are two shorter (2.39 Å) and one longer (2.47 Å) Yb(1)-O(2) bond length. There are two shorter (2.37 Å) and two longer (2.67 Å) Yb(1)-O(3) bond lengths. Si(1) is bonded to four equivalent O(3) atoms to form SiO4 tetrahedra that share corners with four equivalent Be(1)O4 tetrahedra. All Si(1)-O(3) bond lengths are 1.64 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Be(1) and two equivalent Yb(1) atoms to form a mixture of distorted corner and edge-sharing OYb2Be2 tetrahedra. In the second O site, O(2) is bonded to one Be(1) and three equivalent Yb(1) atoms to form distorted OYb3Be tetrahedra that share corners with two equivalent O(1)Yb2Be2 tetrahedra, corners with four equivalent O(2)Yb3Be tetrahedra,  an edgeedge with one O(1)Yb2Be2 tetrahedra, and  an edgeedge with one O(2)Yb3Be tetrahedra. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Be(1), two equivalent Yb(1), and one Si(1) atom.