Materials Data on KNa3Al4(SiO4)4 by Materials Project
KNa3Al4Si4O16 crystallizes in the hexagonal P6_3 space group. The structure is three-dimensional. K1+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of K–O bond distances ranging from 3.01–3.07 Å. Na1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Na–O bond distances ranging from 2.56–2.90 Å. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with four SiO4 tetrahedra. There is one shorter (1.75 Å) and three longer (1.76 Å) Al–O bond length. In the second Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with four SiO4 tetrahedra. There is one shorter (1.74 Å) and three longer (1.76 Å) Al–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 AlO4 tetrahedra. All Si–O bond lengths are 1.64 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four AlO4 tetrahedra. There is one shorter (1.62 Å) and three longer (1.64 Å) Si–O bond length. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Na1+, one Al3+, and one Si4+ atom. In the second O2- site, O2- is bonded in a linear geometry to three equivalent Na1+, one Al3+, and one Si4+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Na1+, one Al3+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Na1+, one Al3+, and one Si4+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one K1+, one Na1+, one Al3+, and one Si4+ atom. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Na1+, one Al3+, and one Si4+ atom.