Materials Data on Ca3SiO4F by Materials Project

Ca3SiO4F is Ilmenite-derived structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Ca sites. In the first Ca site, Ca is bonded in a 6-coordinate geometry to four O and two equivalent F atoms. There are a spread of Ca–O bond distances ranging from 2.35–2.54 Å. There are one shorter (2.38 Å) and one longer (2.65 Å) Ca–F bond lengths. In the second Ca site, Ca is bonded in a 6-coordinate geometry to four O and two equivalent F atoms. There are a spread of Ca–O bond distances ranging from 2.28–2.43 Å. There are one shorter (2.48 Å) and one longer (2.57 Å) Ca–F bond lengths. Si is bonded in a tetrahedral geometry to four O atoms. There is one shorter (1.67 Å) and three longer (1.68 Å) Si–O bond length. There are three inequivalent O sites. In the first O site, O is bonded in a distorted rectangular see-saw-like geometry to three Ca and one Si atom. In the second O site, O is bonded to three Ca and one Si atom to form OCa3Si tetrahedra that share corners with six equivalent FCa6 octahedra. The corner-sharing octahedra tilt angles range from 9–60°. In the third O site, O is bonded in a distorted rectangular see-saw-like geometry to three Ca and one Si atom. F is bonded to six Ca atoms to form FCa6 octahedra that share corners with six equivalent OCa3Si tetrahedra and faces with two equivalent FCa6 octahedra.