Materials Data on Ca3Hf2AlFeSiO12 by Materials Project
Ca3Hf2FeAlSiO12 is Esseneite-derived structured and crystallizes in the tetragonal I-42d space group. The structure is three-dimensional. there are three inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.41–2.71 Å. In the second Ca2+ site, Ca2+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.38–2.69 Å. In the third Ca2+ site, Ca2+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.47–2.57 Å. Hf4+ is bonded to six O2- atoms to form HfO6 octahedra that share corners with two equivalent FeO4 tetrahedra, corners with two equivalent AlO4 tetrahedra, and corners with two SiO4 tetrahedra. There are a spread of Hf–O bond distances ranging from 2.06–2.13 Å. Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with four equivalent HfO6 octahedra. The corner-sharing octahedra tilt angles range from 53–56°. There is two shorter (1.90 Å) and two longer (1.91 Å) Fe–O bond length. Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with four equivalent HfO6 octahedra. The corner-sharing octahedra tilt angles range from 48–51°. There is two shorter (1.79 Å) and two longer (1.80 Å) Al–O bond length. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four equivalent O2- atoms to form SiO4 tetrahedra that share corners with four equivalent HfO6 octahedra. The corner-sharing octahedral tilt angles are 44°. All Si–O bond lengths are 1.66 Å. In the second Si4+ site, Si4+ is bonded to four equivalent O2- atoms to form SiO4 tetrahedra that share corners with four equivalent HfO6 octahedra. The corner-sharing octahedral tilt angles are 42°. All Si–O bond lengths are 1.66 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded to two Ca2+, one Hf4+, and one Fe3+ atom to form a mixture of distorted edge and corner-sharing OCa2HfFe tetrahedra. In the second O2- site, O2- is bonded to two Ca2+, one Hf4+, and one Fe3+ atom to form a mixture of distorted edge and corner-sharing OCa2HfFe tetrahedra. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Hf4+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Hf4+, and one Al3+ atom. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Hf4+, and one Al3+ atom. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Hf4+, and one Si4+ atom.