Materials Data on KMg2AlFeSi3(HO6)2 by Materials Project
KMg2FeAlSi3(HO6)2 crystallizes in the triclinic P1 space group. The structure is two-dimensional and consists of one KMg2FeAlSi3(HO6)2 sheet oriented in the (0, 0, 1) direction. K1+ is bonded in a 3-coordinate geometry to three O2- atoms. There are a spread of K–O bond distances ranging from 2.78–2.81 Å. There are two inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share a cornercorner with one AlO4 tetrahedra, corners with three SiO4 tetrahedra, edges with three equivalent MgO6 octahedra, and edges with three equivalent FeO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.04–2.17 Å. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share a cornercorner with one AlO4 tetrahedra, corners with three SiO4 tetrahedra, edges with three equivalent MgO6 octahedra, and edges with three equivalent FeO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.04–2.14 Å. Fe2+ is bonded to six O2- atoms to form FeO6 octahedra that share a cornercorner with one AlO4 tetrahedra, corners with three SiO4 tetrahedra, and edges with six MgO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.05–2.24 Å. Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share a cornercorner with one FeO6 octahedra, corners with two MgO6 octahedra, and corners with three equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 60–63°. All Al–O bond lengths are 1.76 Å. There are three inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one FeO6 octahedra, corners with two MgO6 octahedra, and corners with three equivalent AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 57–60°. There is three shorter (1.64 Å) and one longer (1.66 Å) Si–O bond length. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one FeO6 octahedra, corners with two MgO6 octahedra, and corners with three equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 55–58°. There is one shorter (1.61 Å) and three longer (1.67 Å) Si–O bond length. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one FeO6 octahedra, corners with two MgO6 octahedra, and corners with three equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 55–59°. There is one shorter (1.61 Å) and three longer (1.67 Å) Si–O bond length. There are two inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.97 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.97 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to two Mg2+, one Fe2+, and one H1+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to two Mg2+, one Fe2+, and one H1+ atom. In the third O2- site, O2- is bonded in a distorted tetrahedral geometry to two Mg2+, one Fe2+, and one Al3+ atom. In the fourth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Mg2+, one Fe2+, and one Si4+ atom. In the fifth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Mg2+, one Fe2+, and one Si4+ atom. In the sixth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Mg2+, one Fe2+, and one Si4+ atom. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Al3+, and one Si4+ atom. In the eighth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Si4+ atoms. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Al3+, and one Si4+ atom. In the tenth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Al3+, and one Si4+ atom. In the eleventh O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the twelfth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Si4+ atoms.