Na2Ca2(CO3)3 crystallizes in the orthorhombic Amm2 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(3), and four equivalent O(4) atoms. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to two equivalent O(1) and four equivalent O(4) atoms. Ca(1) is bonded in a 9-coordinate geometry to one O(3), two equivalent O(1), two equivalent O(2), and four equivalent O(4) atoms. There are two inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to one O(2) and two equivalent O(4) atoms. In the second C site, C(2) is bonded in a trigonal planar geometry to one O(3) and two equivalent O(1) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Na(2), two equivalent Ca(1), and one C(2) atom. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), two equivalent Ca(1), and one C(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to two equivalent Na(1), two equivalent Ca(1), and one C(2) atom. In the fourth O site, O(4) is bonded to one Na(1), one Na(2), two equivalent Ca(1), and one C(1) atom to form a mixture of distorted edge, face, and corner-sharing ONa2Ca2C trigonal bipyramids.
Na2Ca2(CO3)3 crystallizes in the orthorhombic Amm2 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(3), and four equivalent O(4) atoms. Both Na(1)-O(2) bond lengths are 2.45 Å. Both Na(1)-O(3) bond lengths are 2.64 Å. All Na(1)-O(4) bond lengths are 2.56 Å. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to two equivalent O(1) and four equivalent O(4) atoms. Both Na(2)-O(1) bond lengths are 2.44 Å. All Na(2)-O(4) bond lengths are 2.32 Å. Ca(1) is bonded in a 9-coordinate geometry to one O(3), two equivalent O(1), two equivalent O(2), and four equivalent O(4) atoms. The Ca(1)-O(3) bond length is 2.43 Å. There is one shorter (2.44 Å) and one longer (2.59 Å) Ca(1)-O(1) bond length. Both Ca(1)-O(2) bond lengths are 2.57 Å. There are two shorter (2.53 Å) and two longer (2.55 Å) Ca(1)-O(4) bond lengths. There are two inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to one O(2) and two equivalent O(4) atoms. The C(1)-O(2) bond length is 1.29 Å. Both C(1)-O(4) bond lengths are 1.30 Å. In the second C site, C(2) is bonded in a trigonal planar geometry to one O(3) and two equivalent O(1) atoms. The C(2)-O(3) bond length is 1.32 Å. Both C(2)-O(1) bond lengths are 1.29 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Na(2), two equivalent Ca(1), and one C(2) atom. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), two equivalent Ca(1), and one C(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to two equivalent Na(1), two equivalent Ca(1), and one C(2) atom. In the fourth O site, O(4) is bonded to one Na(1), one Na(2), two equivalent Ca(1), and one C(1) atom to form a mixture of distorted edge, face, and corner-sharing ONa2Ca2C trigonal bipyramids.