NaCaFe(SiO3)4 crystallizes in the monoclinic C2 space group. Na(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(4), two equivalent O(5), and two equivalent O(6) atoms. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(3), two equivalent O(5), and two equivalent O(6) atoms. Fe(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form FeO6 octahedra that share corners with two equivalent Si(2)O4 tetrahedra and corners with four equivalent Si(1)O4 tetrahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form SiO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 32-50°. In the second Si site, Si(2) is bonded to one O(2), one O(4), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 52°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Na(1), one Fe(1), and one Si(1) atom. In the second O site, O(2) is bonded in a water-like geometry to one Ca(1) and one Si(2) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Ca(1), one Fe(1), and one Si(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Na(1), one Fe(1), and one Si(2) atom. In the fifth O site, O(5) is bonded in a distorted bent 150 degrees geometry to one Na(1), one Ca(1), one Si(1), and one Si(2) atom. In the sixth O site, O(6) is bonded in a 2-coordinate geometry to one Na(1), one Ca(1), one Si(1), and one Si(2) atom.
NaCaFe(SiO3)4 crystallizes in the monoclinic C2 space group. Na(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(4), two equivalent O(5), and two equivalent O(6) atoms. Both Na(1)-O(1) bond lengths are 2.40 Å. Both Na(1)-O(4) bond lengths are 2.36 Å. Both Na(1)-O(5) bond lengths are 2.85 Å. Both Na(1)-O(6) bond lengths are 2.55 Å. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(3), two equivalent O(5), and two equivalent O(6) atoms. Both Ca(1)-O(2) bond lengths are 2.40 Å. Both Ca(1)-O(3) bond lengths are 2.29 Å. Both Ca(1)-O(5) bond lengths are 2.71 Å. Both Ca(1)-O(6) bond lengths are 2.85 Å. Fe(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form FeO6 octahedra that share corners with two equivalent Si(2)O4 tetrahedra and corners with four equivalent Si(1)O4 tetrahedra. Both Fe(1)-O(1) bond lengths are 2.09 Å. Both Fe(1)-O(3) bond lengths are 2.04 Å. Both Fe(1)-O(4) bond lengths are 1.95 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form SiO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 32-50°. The Si(1)-O(1) bond length is 1.62 Å. The Si(1)-O(3) bond length is 1.62 Å. The Si(1)-O(5) bond length is 1.66 Å. The Si(1)-O(6) bond length is 1.69 Å. In the second Si site, Si(2) is bonded to one O(2), one O(4), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 52°. The Si(2)-O(2) bond length is 1.62 Å. The Si(2)-O(4) bond length is 1.63 Å. The Si(2)-O(5) bond length is 1.67 Å. The Si(2)-O(6) bond length is 1.66 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Na(1), one Fe(1), and one Si(1) atom. In the second O site, O(2) is bonded in a water-like geometry to one Ca(1) and one Si(2) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Ca(1), one Fe(1), and one Si(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Na(1), one Fe(1), and one Si(2) atom. In the fifth O site, O(5) is bonded in a distorted bent 150 degrees geometry to one Na(1), one Ca(1), one Si(1), and one Si(2) atom. In the sixth O site, O(6) is bonded in a 2-coordinate geometry to one Na(1), one Ca(1), one Si(1), and one Si(2) atom.