Be2Ho2SiO7 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. Ho(1) is bonded in a 8-coordinate geometry to one O(2), three equivalent O(1), 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 one Be(1) and three equivalent Ho(1) atoms to form distorted OHo3Be tetrahedra that share corners with two equivalent O(2)Ho2Be2 tetrahedra, corners with four equivalent O(1)Ho3Be tetrahedra,  an edgeedge with one O(2)Ho2Be2 tetrahedra, and  an edgeedge with one O(1)Ho3Be tetrahedra. In the second O site, O(2) is bonded to two equivalent Be(1) and two equivalent Ho(1) atoms to form a mixture of distorted edge and corner-sharing OHo2Be2 tetrahedra. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Be(1), two equivalent Ho(1), and one Si(1) atom.
Be2Ho2SiO7 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 1.59 Å. The Be(1)-O(2) bond length is 1.57 Å. Both Be(1)-O(3) bond lengths are 1.70 Å. Ho(1) is bonded in a 8-coordinate geometry to one O(2), three equivalent O(1), and four equivalent O(3) atoms. The Ho(1)-O(2) bond length is 2.26 Å. There is one shorter (2.31 Å) and two longer (2.40 Å) Ho(1)-O(1) bond lengths. There are two shorter (2.35 Å) and two longer (2.64 Å) Ho(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 one Be(1) and three equivalent Ho(1) atoms to form distorted OHo3Be tetrahedra that share corners with two equivalent O(2)Ho2Be2 tetrahedra, corners with four equivalent O(1)Ho3Be tetrahedra,  an edgeedge with one O(2)Ho2Be2 tetrahedra, and  an edgeedge with one O(1)Ho3Be tetrahedra. In the second O site, O(2) is bonded to two equivalent Be(1) and two equivalent Ho(1) atoms to form a mixture of distorted edge and corner-sharing OHo2Be2 tetrahedra. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Be(1), two equivalent Ho(1), and one Si(1) atom.