Materials Data on Na2MgSiO4 by Materials Project

Na2MgSiO4 crystallizes in the orthorhombic Pna2_1 space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to five O2- atoms to form distorted NaO5 trigonal bipyramids that share corners with three equivalent NaO4 tetrahedra, corners with three equivalent MgO4 tetrahedra, corners with three equivalent SiO4 tetrahedra, corners with two equivalent NaO5 trigonal bipyramids, an edgeedge with one NaO4 tetrahedra, an edgeedge with one MgO4 tetrahedra, and an edgeedge with one SiO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.31–2.78 Å. In the second Na1+ site, Na1+ is bonded to four O2- atoms to form NaO4 tetrahedra that share corners with four equivalent MgO4 tetrahedra, corners with four equivalent SiO4 tetrahedra, corners with three equivalent NaO5 trigonal bipyramids, and an edgeedge with one NaO5 trigonal bipyramid. There are a spread of Na–O bond distances ranging from 2.29–2.35 Å. Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with four equivalent NaO4 tetrahedra, corners with four equivalent SiO4 tetrahedra, corners with three equivalent NaO5 trigonal bipyramids, and an edgeedge with one NaO5 trigonal bipyramid. There are a spread of Mg–O bond distances ranging from 1.95–1.98 Å. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four equivalent NaO4 tetrahedra, corners with four equivalent MgO4 tetrahedra, corners with three equivalent NaO5 trigonal bipyramids, and an edgeedge with one NaO5 trigonal bipyramid. There is one shorter (1.65 Å) and three longer (1.66 Å) Si–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal pyramidal geometry to two Na1+, one Mg2+, and one Si4+ atom. In the second O2- site, O2- is bonded in a 5-coordinate geometry to three Na1+, one Mg2+, and one Si4+ atom. In the third O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Na1+, one Mg2+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one Mg2+, and one Si4+ atom.