Materials Data on Ba3NaSi2B7O20 by Materials Project
NaBa3B7Si2O20 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Na is bonded in a 4-coordinate geometry to four O atoms. There are two shorter (2.36 Å) and two longer (2.40 Å) Na–O bond lengths. There are two inequivalent Ba sites. In the first Ba site, Ba is bonded in a 12-coordinate geometry to ten O atoms. There are a spread of Ba–O bond distances ranging from 2.71–3.08 Å. In the second Ba site, Ba is bonded in a 11-coordinate geometry to eleven O atoms. There are a spread of Ba–O bond distances ranging from 2.72–3.30 Å. There are four inequivalent B sites. In the first B site, B is bonded in a trigonal planar geometry to three O atoms. There is one shorter (1.37 Å) and two longer (1.38 Å) B–O bond length. In the second B site, B is bonded to four O atoms to form corner-sharing BO4 tetrahedra. There is two shorter (1.45 Å) and two longer (1.51 Å) B–O bond length. In the third B site, B is bonded to four O atoms to form BO4 tetrahedra that share corners with two equivalent SiO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.46–1.53 Å. In the fourth B site, B is bonded to four O atoms to form BO4 tetrahedra that share a cornercorner with one BO4 tetrahedra and corners with two equivalent SiO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.44–1.51 Å. Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with four BO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.63–1.66 Å. There are ten inequivalent O sites. In the first O site, O is bonded in a bent 120 degrees geometry to two Ba and two B atoms. In the second O site, O is bonded in a bent 120 degrees geometry to two Ba, one B, and one Si atom. In the third O site, O is bonded in a bent 120 degrees geometry to one Ba and two B atoms. In the fourth O site, O is bonded in a distorted bent 120 degrees geometry to two equivalent Ba, one B, and one Si atom. In the fifth O site, O is bonded in a distorted bent 120 degrees geometry to one Ba and two B atoms. In the sixth O site, O is bonded in a bent 120 degrees geometry to one Ba and two B atoms. In the seventh O site, O is bonded in a bent 120 degrees geometry to one Ba, one B, and one Si atom. In the eighth O site, O is bonded to one Na and three Ba atoms to form corner-sharing OBa3Na tetrahedra. In the ninth O site, O is bonded in a 2-coordinate geometry to one Na, one Ba, one B, and one Si atom. In the tenth O site, O is bonded in a single-bond geometry to two Ba and one B atom.