Materials Data on Ba6Mg7F26 by Materials Project
Ba6Mg7F26 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded to twelve F1- atoms to form distorted BaF12 cuboctahedra that share corners with two equivalent BaF12 cuboctahedra, a faceface with one BaF12 cuboctahedra, and faces with six MgF6 octahedra. There are a spread of Ba–F bond distances ranging from 2.70–3.04 Å. In the second Ba2+ site, Ba2+ is bonded in a 12-coordinate geometry to twelve F1- atoms. There are a spread of Ba–F bond distances ranging from 2.63–3.29 Å. There are four inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six F1- atoms to form a mixture of edge and corner-sharing MgF6 octahedra. The corner-sharing octahedra tilt angles range from 48–50°. There are a spread of Mg–F bond distances ranging from 1.99–2.03 Å. In the second Mg2+ site, Mg2+ is bonded to six F1- atoms to form MgF6 octahedra that share corners with four MgF6 octahedra and faces with two equivalent BaF12 cuboctahedra. The corner-sharing octahedra tilt angles range from 2–50°. There are a spread of Mg–F bond distances ranging from 1.94–2.09 Å. In the third Mg2+ site, Mg2+ is bonded to six F1- atoms to form distorted MgF6 octahedra that share corners with three MgF6 octahedra and faces with two equivalent BaF12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–48°. There are a spread of Mg–F bond distances ranging from 1.99–2.31 Å. In the fourth Mg2+ site, Mg2+ is bonded to six F1- atoms to form MgF6 octahedra that share corners with six MgF6 octahedra and faces with four equivalent BaF12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are two shorter (1.99 Å) and four longer (2.02 Å) Mg–F bond lengths. There are seven inequivalent F1- sites. In the first F1- site, F1- is bonded in a linear geometry to four Ba2+ and two Mg2+ atoms. In the second F1- site, F1- is bonded in a 2-coordinate geometry to two equivalent Ba2+ and two Mg2+ atoms. In the third F1- site, F1- is bonded in a distorted trigonal planar geometry to three Mg2+ atoms. In the fourth F1- site, F1- is bonded in a 2-coordinate geometry to four Ba2+ and two Mg2+ atoms. In the fifth F1- site, F1- is bonded in an L-shaped geometry to two equivalent Ba2+ and two equivalent Mg2+ atoms. In the sixth F1- site, F1- is bonded in a distorted single-bond geometry to three Ba2+ and one Mg2+ atom. In the seventh F1- site, F1- is bonded in a 1-coordinate geometry to three Ba2+ and one Mg2+ atom.