DOE OSTI2020
KCo3AlSi3(HO6)2 crystallizes in the triclinic P1 space group. The structure is three-dimensional. K1+ is bonded in a 6-coordinate geometry to one H1+ and twelve O2- atoms. The K–H bond length is 3.01 Å. There are a spread of K–O bond distances ranging from 2.82–3.46 Å. There are three inequivalent Co2+ sites. In the first Co2+ site, Co2+ is bonded to six O2- atoms to form CoO6 octahedra that share a cornercorner with one AlO4 tetrahedra, corners with three SiO4 tetrahedra, and edges with six CoO6 octahedra. There are a spread of Co–O bond distances ranging from 2.03–2.20 Å. In the second Co2+ site, Co2+ is bonded to six O2- atoms to form CoO6 octahedra that share a cornercorner with one AlO4 tetrahedra, corners with three SiO4 tetrahedra, and edges with six CoO6 octahedra. There are a spread of Co–O bond distances ranging from 2.05–2.17 Å. In the third Co2+ site, Co2+ is bonded to six O2- atoms to form CoO6 octahedra that share a cornercorner with one AlO4 tetrahedra, corners with three SiO4 tetrahedra, and edges with six CoO6 octahedra. There are a spread of Co–O bond distances ranging from 2.05–2.20 Å. Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with three CoO6 octahedra and corners with three equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 60–61°. All Al–O bond lengths are 1.76 Å. There are three inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three CoO6 octahedra and corners with three equivalent AlO4 tetrahedra. The corner-sharing octahedral tilt angles are 57°. There is three shorter (1.64 Å) and one longer (1.67 Å) Si–O bond length. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three CoO6 octahedra and corners with three equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 55–56°. There is one shorter (1.61 Å) and three longer (1.67 Å) Si–O bond length. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three CoO6 octahedra and corners with three equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 54–57°. There is one shorter (1.61 Å) and three longer (1.67 Å) Si–O bond length. There are two inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one K1+ and one O2- atom. The H–O bond length is 0.97 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.97 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to three Co2+ and one H1+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to three Co2+ and one H1+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent K1+, one Al3+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent K1+ and two Si4+ atoms. In the fifth O2- site, O2- is bonded in a distorted tetrahedral geometry to three Co2+ and one Al3+ atom. In the sixth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Co2+ and one Si4+ atom. In the seventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Co2+ and one Si4+ atom. In the eighth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Co2+ and one Si4+ atom. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent K1+, one Al3+, and one Si4+ atom. In the tenth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent K1+, one Al3+, and one Si4+ atom. In the eleventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent K1+ and two Si4+ atoms. In the twelfth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent K1+ and two Si4+ atoms.