Li2CoSiO4 is beta beryllia-derived structured and crystallizes in the monoclinic C2/m space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form LiO4 tetrahedra that share corners with two equivalent Co(1)O4 tetrahedra, corners with four equivalent Li(2)O4 tetrahedra, corners with four equivalent Si(1)O4 tetrahedra, and  an edgeedge with one Li(1)O4 tetrahedra. In the second Li site, Li(2) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form distorted LiO4 tetrahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with four equivalent Li(1)O4 tetrahedra, corners with four equivalent Co(1)O4 tetrahedra, and  an edgeedge with one Si(1)O4 tetrahedra. Co(1) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form CoO4 tetrahedra that share corners with two equivalent Li(1)O4 tetrahedra, corners with four equivalent Li(2)O4 tetrahedra, corners with four equivalent Si(1)O4 tetrahedra, and  an edgeedge with one Co(1)O4 tetrahedra. Si(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form SiO4 tetrahedra that share corners with two equivalent Li(2)O4 tetrahedra, corners with four equivalent Li(1)O4 tetrahedra, corners with four equivalent Co(1)O4 tetrahedra, and  an edgeedge with one Li(2)O4 tetrahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Li(2), two equivalent Co(1), and one Si(1) atom to form distorted OLiCo2Si tetrahedra that share corners with two equivalent O(2)Li3Si tetrahedra, corners with eight equivalent O(3)Li2CoSi tetrahedra, and  an edgeedge with one O(1)LiCo2Si tetrahedra. In the second O site, O(2) is bonded to one Li(2), two equivalent Li(1), and one Si(1) atom to form OLi3Si tetrahedra that share corners with two equivalent O(1)LiCo2Si tetrahedra, corners with eight equivalent O(3)Li2CoSi tetrahedra, and  an edgeedge with one O(2)Li3Si tetrahedra. In the third O site, O(3) is bonded to one Li(1), one Li(2), one Co(1), and one Si(1) atom to form OLi2CoSi tetrahedra that share corners with two equivalent O(3)Li2CoSi tetrahedra, corners with four equivalent O(2)Li3Si tetrahedra, corners with four equivalent O(1)LiCo2Si tetrahedra, and  an edgeedge with one O(3)Li2CoSi tetrahedra.
Li2CoSiO4 is beta beryllia-derived structured and crystallizes in the monoclinic C2/m space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form LiO4 tetrahedra that share corners with two equivalent Co(1)O4 tetrahedra, corners with four equivalent Li(2)O4 tetrahedra, corners with four equivalent Si(1)O4 tetrahedra, and  an edgeedge with one Li(1)O4 tetrahedra. Both Li(1)-O(2) bond lengths are 1.99 Å. Both Li(1)-O(3) bond lengths are 1.98 Å. In the second Li site, Li(2) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form distorted LiO4 tetrahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with four equivalent Li(1)O4 tetrahedra, corners with four equivalent Co(1)O4 tetrahedra, and  an edgeedge with one Si(1)O4 tetrahedra. The Li(2)-O(1) bond length is 2.08 Å. The Li(2)-O(2) bond length is 1.94 Å. Both Li(2)-O(3) bond lengths are 2.08 Å. Co(1) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form CoO4 tetrahedra that share corners with two equivalent Li(1)O4 tetrahedra, corners with four equivalent Li(2)O4 tetrahedra, corners with four equivalent Si(1)O4 tetrahedra, and  an edgeedge with one Co(1)O4 tetrahedra. Both Co(1)-O(1) bond lengths are 2.04 Å. Both Co(1)-O(3) bond lengths are 1.94 Å. Si(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form SiO4 tetrahedra that share corners with two equivalent Li(2)O4 tetrahedra, corners with four equivalent Li(1)O4 tetrahedra, corners with four equivalent Co(1)O4 tetrahedra, and  an edgeedge with one Li(2)O4 tetrahedra. The Si(1)-O(1) bond length is 1.69 Å. The Si(1)-O(2) bond length is 1.62 Å. Both Si(1)-O(3) bond lengths are 1.66 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Li(2), two equivalent Co(1), and one Si(1) atom to form distorted OLiCo2Si tetrahedra that share corners with two equivalent O(2)Li3Si tetrahedra, corners with eight equivalent O(3)Li2CoSi tetrahedra, and  an edgeedge with one O(1)LiCo2Si tetrahedra. In the second O site, O(2) is bonded to one Li(2), two equivalent Li(1), and one Si(1) atom to form OLi3Si tetrahedra that share corners with two equivalent O(1)LiCo2Si tetrahedra, corners with eight equivalent O(3)Li2CoSi tetrahedra, and  an edgeedge with one O(2)Li3Si tetrahedra. In the third O site, O(3) is bonded to one Li(1), one Li(2), one Co(1), and one Si(1) atom to form OLi2CoSi tetrahedra that share corners with two equivalent O(3)Li2CoSi tetrahedra, corners with four equivalent O(2)Li3Si tetrahedra, corners with four equivalent O(1)LiCo2Si tetrahedra, and  an edgeedge with one O(3)Li2CoSi tetrahedra.