Be2Eu2SiO7 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. Eu(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 in a 4-coordinate geometry to two equivalent Be(1) and two equivalent Eu(1) atoms. In the second O site, O(2) is bonded to one Be(1) and three equivalent Eu(1) atoms to form a mixture of distorted edge and corner-sharing OEu3Be tetrahedra. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Be(1), two equivalent Eu(1), and one Si(1) atom.
Be2Eu2SiO7 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 1.63 Å. Both Be(1)-O(3) bond lengths are 1.71 Å. Eu(1) is bonded in a 8-coordinate geometry to one O(1), three equivalent O(2), and four equivalent O(3) atoms. The Eu(1)-O(1) bond length is 2.35 Å. There is one shorter (2.36 Å) and two longer (2.47 Å) Eu(1)-O(2) bond lengths. There are two shorter (2.46 Å) and two longer (2.69 Å) Eu(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 1.65 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Be(1) and two equivalent Eu(1) atoms. In the second O site, O(2) is bonded to one Be(1) and three equivalent Eu(1) atoms to form a mixture of distorted edge and corner-sharing OEu3Be tetrahedra. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Be(1), two equivalent Eu(1), and one Si(1) atom.