DOE OSTI2020
LaKOCO3 crystallizes in the triclinic P1 space group. The structure is two-dimensional and consists of one K2O2 sheet oriented in the (0, 0, 1) direction and one LaCO3 sheet oriented in the (0, 0, 1) direction. In the K2O2 sheet, there are four inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to five O2- atoms to form a mixture of edge and corner-sharing KO5 square pyramids. There are a spread of K–O bond distances ranging from 2.57–2.98 Å. In the second K1+ site, K1+ is bonded to five O2- atoms to form a mixture of edge and corner-sharing KO5 square pyramids. There are a spread of K–O bond distances ranging from 2.56–2.98 Å. In the third K1+ site, K1+ is bonded to five O2- atoms to form a mixture of edge and corner-sharing KO5 square pyramids. There are a spread of K–O bond distances ranging from 2.56–2.98 Å. In the fourth K1+ site, K1+ is bonded to five O2- atoms to form a mixture of edge and corner-sharing KO5 square pyramids. There are a spread of K–O bond distances ranging from 2.57–2.98 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to five K1+ atoms to form a mixture of edge and corner-sharing OK5 square pyramids. In the second O2- site, O2- is bonded to five K1+ atoms to form a mixture of edge and corner-sharing OK5 square pyramids. In the third O2- site, O2- is bonded to five K1+ atoms to form a mixture of edge and corner-sharing OK5 square pyramids. In the fourth O2- site, O2- is bonded to five K1+ atoms to form a mixture of edge and corner-sharing OK5 square pyramids. In the LaCO3 sheet, there are four inequivalent La3+ sites. In the first La3+ site, La3+ is bonded in a distorted hexagonal planar geometry to six O2- atoms. There are a spread of La–O bond distances ranging from 2.38–2.49 Å. In the second La3+ site, La3+ is bonded in a distorted hexagonal planar geometry to six O2- atoms. There are a spread of La–O bond distances ranging from 2.38–2.49 Å. In the third La3+ site, La3+ is bonded in a distorted hexagonal planar geometry to six O2- atoms. There are a spread of La–O bond distances ranging from 2.38–2.49 Å. In the fourth La3+ site, La3+ is bonded in a distorted hexagonal planar geometry to six O2- atoms. There are a spread of La–O bond distances ranging from 2.38–2.49 Å. There are four inequivalent C4+ sites. In the first C4+ site, C4+ is bonded in a bent 120 degrees geometry to two O2- atoms. Both C–O bond lengths are 1.27 Å. In the second C4+ site, C4+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.26 Å) and one longer (1.27 Å) C–O bond length. In the third C4+ site, C4+ is bonded in a bent 120 degrees geometry to two O2- atoms. Both C–O bond lengths are 1.26 Å. In the fourth C4+ site, C4+ is bonded in a bent 120 degrees geometry to two O2- atoms. Both C–O bond lengths are 1.26 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted L-shaped geometry to one La3+ and one C4+ atom. In the second O2- site, O2- is bonded in a distorted L-shaped geometry to one La3+ and one C4+ atom. In the third O2- site, O2- is bonded in a distorted L-shaped geometry to one La3+ and one C4+ atom. In the fourth O2- site, O2- is bonded in a distorted L-shaped geometry to one La3+ and one C4+ atom. In the fifth O2- site, O2- is bonded to four La3+ atoms to form a mixture of edge and corner-sharing OLa4 tetrahedra. In the sixth O2- site, O2- is bonded to four La3+ atoms to form a mixture of edge and corner-sharing OLa4 tetrahedra. In the seventh O2- site, O2- is bonded in a distorted L-shaped geometry to one La3+ and one C4+ atom. In the eighth O2- site, O2- is bonded in a distorted L-shaped geometry to one La3+ and one C4+ atom. In the ninth O2- site, O2- is bonded to four La3+ atoms to form a mixture of edge and corner-sharing OLa4 tetrahedra. In the tenth O2- site, O2- is bonded in a distorted L-shaped geometry to one La3+ and one C4+ atom. In the eleventh O2- site, O2- is bonded to four La3+ atoms to form a mixture of edge and corner-sharing OLa4 tetrahedra. In the twelfth O2- site, O2- is bonded in a distorted L-shaped geometry to one La3+ and one C4+ atom.