EuSi2O2N2 crystallizes in the triclinic P1 space group. There are four inequivalent Eu sites. In the first Eu site, Eu(1) is bonded in a 7-coordinate geometry to one N(5), one O(1), one O(4), one O(5), one O(6), one O(7), and one O(8) atom. In the second Eu site, Eu(2) is bonded in a 7-coordinate geometry to one N(4), one O(1), one O(2), one O(3), one O(5), one O(6), and one O(8) atom. In the third Eu site, Eu(3) is bonded in a 7-coordinate geometry to one N(1), one O(2), one O(3), one O(4), one O(5), one O(7), and one O(8) atom. In the fourth Eu site, Eu(4) is bonded in a 7-coordinate geometry to one N(3), one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom. There are eight inequivalent Si sites. In the first Si site, Si(1) is bonded to one N(4), one N(5), one N(7), and one O(6) atom to form corner-sharing SiN3O tetrahedra. In the second Si site, Si(2) is bonded to one N(2), one N(7), one N(8), and one O(7) atom to form corner-sharing SiN3O tetrahedra. In the third Si site, Si(3) is bonded to one N(3), one N(6), one N(7), and one O(3) atom to form corner-sharing SiN3O tetrahedra. In the fourth Si site, Si(4) is bonded to one N(2), one N(4), one N(6), and one O(8) atom to form corner-sharing SiN3O tetrahedra. In the fifth Si site, Si(5) is bonded to one N(1), one N(3), one N(4), and one O(2) atom to form corner-sharing SiN3O tetrahedra. In the sixth Si site, Si(6) is bonded to one N(3), one N(5), one N(8), and one O(1) atom to form corner-sharing SiN3O tetrahedra. In the seventh Si site, Si(7) is bonded to one N(1), one N(6), one N(8), and one O(5) atom to form corner-sharing SiN3O tetrahedra. In the eighth Si site, Si(8) is bonded to one N(1), one N(2), one N(5), and one O(4) atom to form corner-sharing SiN3O tetrahedra. There are eight inequivalent N sites. In the first N site, N(1) is bonded in a distorted trigonal planar geometry to one Eu(3), one Si(5), one Si(7), and one Si(8) atom. In the second N site, N(2) is bonded in a trigonal planar geometry to one Si(2), one Si(4), and one Si(8) atom. In the third N site, N(3) is bonded in a distorted trigonal planar geometry to one Eu(4), one Si(3), one Si(5), and one Si(6) atom. In the fourth N site, N(4) is bonded in a trigonal planar geometry to one Eu(2), one Si(1), one Si(4), and one Si(5) atom. In the fifth N site, N(5) is bonded in a distorted trigonal planar geometry to one Eu(1), one Si(1), one Si(6), and one Si(8) atom. In the sixth N site, N(6) is bonded in a trigonal planar geometry to one Si(3), one Si(4), and one Si(7) atom. In the seventh N site, N(7) is bonded in a trigonal planar geometry to one Si(1), one Si(2), and one Si(3) atom. In the eighth N site, N(8) is bonded in a trigonal planar geometry to one Si(2), one Si(6), and one Si(7) atom. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Eu(1), one Eu(2), one Eu(4), and one Si(6) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Eu(2), one Eu(3), one Eu(4), and one Si(5) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Eu(2), one Eu(3), one Eu(4), and one Si(3) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one Eu(1), one Eu(3), one Eu(4), and one Si(8) atom. In the fifth O site, O(5) is bonded to one Eu(1), one Eu(2), one Eu(3), and one Si(7) atom to form distorted corner-sharing OEu3Si tetrahedra. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one Eu(1), one Eu(2), one Eu(4), and one Si(1) atom. In the seventh O site, O(7) is bonded to one Eu(1), one Eu(3), one Eu(4), and one Si(2) atom to form distorted corner-sharing OEu3Si tetrahedra. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Eu(1), one Eu(2), one Eu(3), and one Si(4) atom.
EuSi2O2N2 crystallizes in the triclinic P1 space group. There are four inequivalent Eu sites. In the first Eu site, Eu(1) is bonded in a 7-coordinate geometry to one N(5), one O(1), one O(4), one O(5), one O(6), one O(7), and one O(8) atom. The Eu(1)-N(5) bond length is 2.84 Å. The Eu(1)-O(1) bond length is 2.69 Å. The Eu(1)-O(4) bond length is 2.56 Å. The Eu(1)-O(5) bond length is 2.53 Å. The Eu(1)-O(6) bond length is 2.53 Å. The Eu(1)-O(7) bond length is 2.53 Å. The Eu(1)-O(8) bond length is 2.66 Å. In the second Eu site, Eu(2) is bonded in a 7-coordinate geometry to one N(4), one O(1), one O(2), one O(3), one O(5), one O(6), and one O(8) atom. The Eu(2)-N(4) bond length is 2.96 Å. The Eu(2)-O(1) bond length is 2.51 Å. The Eu(2)-O(2) bond length is 2.49 Å. The Eu(2)-O(3) bond length is 2.56 Å. The Eu(2)-O(5) bond length is 2.74 Å. The Eu(2)-O(6) bond length is 2.68 Å. The Eu(2)-O(8) bond length is 2.56 Å. In the third Eu site, Eu(3) is bonded in a 7-coordinate geometry to one N(1), one O(2), one O(3), one O(4), one O(5), one O(7), and one O(8) atom. The Eu(3)-N(1) bond length is 2.83 Å. The Eu(3)-O(2) bond length is 2.68 Å. The Eu(3)-O(3) bond length is 2.51 Å. The Eu(3)-O(4) bond length is 2.55 Å. The Eu(3)-O(5) bond length is 2.57 Å. The Eu(3)-O(7) bond length is 2.68 Å. The Eu(3)-O(8) bond length is 2.53 Å. In the fourth Eu site, Eu(4) is bonded in a 7-coordinate geometry to one N(3), one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom. The Eu(4)-N(3) bond length is 2.94 Å. The Eu(4)-O(1) bond length is 2.50 Å. The Eu(4)-O(2) bond length is 2.51 Å. The Eu(4)-O(3) bond length is 2.74 Å. The Eu(4)-O(4) bond length is 2.72 Å. The Eu(4)-O(6) bond length is 2.54 Å. The Eu(4)-O(7) bond length is 2.52 Å. There are eight inequivalent Si sites. In the first Si site, Si(1) is bonded to one N(4), one N(5), one N(7), and one O(6) atom to form corner-sharing SiN3O tetrahedra. The Si(1)-N(4) bond length is 1.77 Å. The Si(1)-N(5) bond length is 1.76 Å. The Si(1)-N(7) bond length is 1.73 Å. The Si(1)-O(6) bond length is 1.63 Å. In the second Si site, Si(2) is bonded to one N(2), one N(7), one N(8), and one O(7) atom to form corner-sharing SiN3O tetrahedra. The Si(2)-N(2) bond length is 1.75 Å. The Si(2)-N(7) bond length is 1.76 Å. The Si(2)-N(8) bond length is 1.75 Å. The Si(2)-O(7) bond length is 1.64 Å. In the third Si site, Si(3) is bonded to one N(3), one N(6), one N(7), and one O(3) atom to form corner-sharing SiN3O tetrahedra. The Si(3)-N(3) bond length is 1.75 Å. The Si(3)-N(6) bond length is 1.76 Å. The Si(3)-N(7) bond length is 1.75 Å. The Si(3)-O(3) bond length is 1.63 Å. In the fourth Si site, Si(4) is bonded to one N(2), one N(4), one N(6), and one O(8) atom to form corner-sharing SiN3O tetrahedra. The Si(4)-N(2) bond length is 1.76 Å. The Si(4)-N(4) bond length is 1.77 Å. The Si(4)-N(6) bond length is 1.74 Å. The Si(4)-O(8) bond length is 1.64 Å. In the fifth Si site, Si(5) is bonded to one N(1), one N(3), one N(4), and one O(2) atom to form corner-sharing SiN3O tetrahedra. The Si(5)-N(1) bond length is 1.76 Å. The Si(5)-N(3) bond length is 1.75 Å. The Si(5)-N(4) bond length is 1.73 Å. The Si(5)-O(2) bond length is 1.63 Å. In the sixth Si site, Si(6) is bonded to one N(3), one N(5), one N(8), and one O(1) atom to form corner-sharing SiN3O tetrahedra. The Si(6)-N(3) bond length is 1.75 Å. The Si(6)-N(5) bond length is 1.75 Å. The Si(6)-N(8) bond length is 1.75 Å. The Si(6)-O(1) bond length is 1.63 Å. In the seventh Si site, Si(7) is bonded to one N(1), one N(6), one N(8), and one O(5) atom to form corner-sharing SiN3O tetrahedra. The Si(7)-N(1) bond length is 1.75 Å. The Si(7)-N(6) bond length is 1.75 Å. The Si(7)-N(8) bond length is 1.76 Å. The Si(7)-O(5) bond length is 1.63 Å. In the eighth Si site, Si(8) is bonded to one N(1), one N(2), one N(5), and one O(4) atom to form corner-sharing SiN3O tetrahedra. The Si(8)-N(1) bond length is 1.77 Å. The Si(8)-N(2) bond length is 1.74 Å. The Si(8)-N(5) bond length is 1.75 Å. The Si(8)-O(4) bond length is 1.63 Å. There are eight inequivalent N sites. In the first N site, N(1) is bonded in a distorted trigonal planar geometry to one Eu(3), one Si(5), one Si(7), and one Si(8) atom. In the second N site, N(2) is bonded in a trigonal planar geometry to one Si(2), one Si(4), and one Si(8) atom. In the third N site, N(3) is bonded in a distorted trigonal planar geometry to one Eu(4), one Si(3), one Si(5), and one Si(6) atom. In the fourth N site, N(4) is bonded in a trigonal planar geometry to one Eu(2), one Si(1), one Si(4), and one Si(5) atom. In the fifth N site, N(5) is bonded in a distorted trigonal planar geometry to one Eu(1), one Si(1), one Si(6), and one Si(8) atom. In the sixth N site, N(6) is bonded in a trigonal planar geometry to one Si(3), one Si(4), and one Si(7) atom. In the seventh N site, N(7) is bonded in a trigonal planar geometry to one Si(1), one Si(2), and one Si(3) atom. In the eighth N site, N(8) is bonded in a trigonal planar geometry to one Si(2), one Si(6), and one Si(7) atom. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Eu(1), one Eu(2), one Eu(4), and one Si(6) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Eu(2), one Eu(3), one Eu(4), and one Si(5) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Eu(2), one Eu(3), one Eu(4), and one Si(3) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one Eu(1), one Eu(3), one Eu(4), and one Si(8) atom. In the fifth O site, O(5) is bonded to one Eu(1), one Eu(2), one Eu(3), and one Si(7) atom to form distorted corner-sharing OEu3Si tetrahedra. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one Eu(1), one Eu(2), one Eu(4), and one Si(1) atom. In the seventh O site, O(7) is bonded to one Eu(1), one Eu(3), one Eu(4), and one Si(2) atom to form distorted corner-sharing OEu3Si tetrahedra. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Eu(1), one Eu(2), one Eu(3), and one Si(4) atom.