DOE OSTI2020
Co3(PO4)4 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are three inequivalent Co4+ sites. In the first Co4+ site, Co4+ is bonded to five O2- atoms to form CoO5 trigonal bipyramids that share corners with three PO4 tetrahedra, an edgeedge with one CoO6 octahedra, and an edgeedge with one PO4 tetrahedra. There are a spread of Co–O bond distances ranging from 1.83–2.00 Å. In the second Co4+ site, Co4+ is bonded to five O2- atoms to form CoO5 square pyramids that share corners with five PO4 tetrahedra. There are a spread of Co–O bond distances ranging from 1.88–1.97 Å. In the third Co4+ site, Co4+ is bonded to six O2- atoms to form distorted CoO6 octahedra that share corners with six PO4 tetrahedra and an edgeedge with one CoO5 trigonal bipyramid. There are a spread of Co–O bond distances ranging from 1.82–2.44 Å. There are four inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent CoO6 octahedra and a cornercorner with one CoO5 square pyramid. The corner-sharing octahedra tilt angles range from 26–49°. There is one shorter (1.53 Å) and three longer (1.55 Å) P–O bond length. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one CoO6 octahedra, corners with two equivalent CoO5 square pyramids, and a cornercorner with one CoO5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 40°. There are a spread of P–O bond distances ranging from 1.53–1.58 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one CoO6 octahedra, corners with two equivalent CoO5 square pyramids, and a cornercorner with one CoO5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 37°. There are a spread of P–O bond distances ranging from 1.52–1.57 Å. In the fourth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent CoO6 octahedra, a cornercorner with one CoO5 trigonal bipyramid, and an edgeedge with one CoO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 30–56°. There are a spread of P–O bond distances ranging from 1.49–1.62 Å. There are sixteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one Co4+ and one P5+ atom. In the second O2- site, O2- is bonded in a distorted T-shaped geometry to two Co4+ and one P5+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to two Co4+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to one Co4+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Co4+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a bent 120 degrees geometry to one Co4+ and one P5+ atom. In the seventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Co4+ and one P5+ atom. In the eighth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Co4+ and one P5+ atom. In the ninth O2- site, O2- is bonded in a single-bond geometry to one P5+ atom. In the tenth O2- site, O2- is bonded in a water-like geometry to one Co4+ and one P5+ atom. In the eleventh O2- site, O2- is bonded in a bent 150 degrees geometry to one Co4+ and one P5+ atom. In the twelfth O2- site, O2- is bonded in a bent 150 degrees geometry to one Co4+ and one P5+ atom. In the thirteenth O2- site, O2- is bonded in a bent 150 degrees geometry to one Co4+ and one P5+ atom. In the fourteenth O2- site, O2- is bonded in a single-bond geometry to one P5+ atom. In the fifteenth O2- site, O2- is bonded in a bent 150 degrees geometry to one Co4+ and one P5+ atom. In the sixteenth O2- site, O2- is bonded in a bent 150 degrees geometry to one Co4+ and one P5+ atom.