Materials Data on K2MgSiO4 by Materials Project

Abstract

K2MgSiO4 crystallizes in the orthorhombic Pca2_1 space group. The structure is three-dimensional. there are four inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of K–O bond distances ranging from 2.83–3.25 Å. In the second K1+ site, K1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of K–O bond distances ranging from 2.68–2.78 Å. In the third K1+ site, K1+ is bonded in a 6-coordinate geometry to eight O2- atoms. There are a spread of K–O bond distances ranging from 2.79–3.28 Å. In the fourth K1+ site, K1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of K–O bond distances ranging from 2.71–3.08 Å. There are two inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with four SiO4 tetrahedra. There is two shorter (1.96 Å) and two longer (1.97 Å) Mg–O bond length. In the second Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with four SiO4 tetrahedra. There is three shorter (1.96 Å) and one longer (1.97 Å) Mg–O bond length. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four MgO4 tetrahedra. All Si–O bond lengths are 1.66 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four MgO4 tetrahedra. There is two shorter (1.65 Å) and two longer (1.66 Å) Si–O bond length. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to four K1+, one Mg2+, and one Si4+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to three K1+, one Mg2+, and one Si4+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to three K1+, one Mg2+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to three K1+, one Mg2+, and one Si4+ atom. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to two K1+, one Mg2+, and one Si4+ atom. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to four K1+, one Mg2+, and one Si4+ atom. In the seventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to three K1+, one Mg2+, and one Si4+ atom. In the eighth O2- site, O2- is bonded in a 2-coordinate geometry to three K1+, one Mg2+, and one Si4+ atom.