DOE OSTI2020
La5Ta22O62 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are five inequivalent La sites. In the first La site, La is bonded in a 6-coordinate geometry to six O atoms. There are two shorter (2.52 Å) and four longer (2.71 Å) La–O bond lengths. In the second La site, La is bonded in a 10-coordinate geometry to ten O atoms. There are a spread of La–O bond distances ranging from 2.58–2.78 Å. In the third La site, La is bonded in a 10-coordinate geometry to ten O atoms. There are a spread of La–O bond distances ranging from 2.55–2.79 Å. In the fourth La site, La is bonded in a 11-coordinate geometry to eleven O atoms. There are a spread of La–O bond distances ranging from 2.56–3.25 Å. In the fifth La site, La is bonded in a 11-coordinate geometry to eleven O atoms. There are a spread of La–O bond distances ranging from 2.55–3.26 Å. There are nine inequivalent Ta sites. In the first Ta site, Ta is bonded to six O atoms to form TaO6 octahedra that share corners with five TaO6 octahedra and an edgeedge with one TaO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 9–49°. There are a spread of Ta–O bond distances ranging from 1.91–2.09 Å. In the second Ta site, Ta is bonded to six O atoms to form TaO6 octahedra that share corners with six TaO6 octahedra and an edgeedge with one TaO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 8–41°. There are a spread of Ta–O bond distances ranging from 1.92–2.08 Å. In the third Ta site, Ta is bonded to six O atoms to form TaO6 octahedra that share corners with six TaO6 octahedra and an edgeedge with one TaO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 8–41°. There are a spread of Ta–O bond distances ranging from 1.92–2.07 Å. In the fourth Ta site, Ta is bonded to seven O atoms to form TaO7 pentagonal bipyramids that share corners with two equivalent TaO7 pentagonal bipyramids and edges with four TaO6 octahedra. There are a spread of Ta–O bond distances ranging from 1.96–2.14 Å. In the fifth Ta site, Ta is bonded to seven O atoms to form TaO7 pentagonal bipyramids that share corners with two equivalent TaO7 pentagonal bipyramids and edges with four TaO6 octahedra. There are a spread of Ta–O bond distances ranging from 1.96–2.14 Å. In the sixth Ta site, Ta is bonded to six O atoms to form TaO6 octahedra that share corners with six TaO6 octahedra and an edgeedge with one TaO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 3–33°. There are a spread of Ta–O bond distances ranging from 1.92–2.08 Å. In the seventh Ta site, Ta is bonded to six O atoms to form TaO6 octahedra that share corners with five TaO6 octahedra and an edgeedge with one TaO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 16–58°. There are a spread of Ta–O bond distances ranging from 1.93–2.13 Å. In the eighth Ta site, Ta is bonded to six O atoms to form TaO6 octahedra that share corners with five TaO6 octahedra and an edgeedge with one TaO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 16–58°. There are a spread of Ta–O bond distances ranging from 1.93–2.13 Å. In the ninth Ta site, Ta is bonded to six O atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedra tilt angles range from 7–41°. There are a spread of Ta–O bond distances ranging from 1.94–2.08 Å. There are forty-two inequivalent O sites. In the first O site, O is bonded in a distorted bent 150 degrees geometry to one La and two Ta atoms. In the second O site, O is bonded in a distorted bent 150 degrees geometry to one La and two Ta atoms. The O–Ta bond length is 1.99 Å. In the third O site, O is bonded in a bent 150 degrees geometry to two Ta atoms. The O–Ta bond length is 1.92 Å. In the fourth O site, O is bonded in a bent 150 degrees geometry to two Ta atoms. The O–Ta bond length is 1.91 Å. In the fifth O site, O is bonded in a trigonal non-coplanar geometry to one La and two equivalent Ta atoms. In the sixth O site, O is bonded in a linear geometry to two equivalent Ta atoms. In the seventh O site, O is bonded in a linear geometry to two equivalent Ta atoms. Both O–Ta bond lengths are 1.98 Å. In the eighth O site, O is bonded in a linear geometry to two equivalent Ta atoms. Both O–Ta bond lengths are 1.94 Å. In the ninth O site, O is bonded in a linear geometry to two equivalent Ta atoms. In the tenth O site, O is bonded in a distorted trigonal non-coplanar geometry to three Ta atoms. In the eleventh O site, O is bonded in a distorted trigonal non-coplanar geometry to three Ta atoms. The O–Ta bond length is 2.09 Å. In the twelfth O site, O is bonded in a linear geometry to one La and two equivalent Ta atoms. In the thirteenth O site, O is bonded in a linear geometry to one La and two equivalent Ta atoms. In the fourteenth O site, O is bonded in a linear geometry to one La and two equivalent Ta atoms. In the fifteenth O site, O is bonded in a linear geometry to one La and two equivalent Ta atoms. In the sixteenth O site, O is bonded to two La and two Ta atoms to form a mixture of distorted edge and corner-sharing OLa2Ta2 tetrahedra. In the seventeenth O site, O is bonded to two La and two Ta atoms to form a mixture of distorted edge and corner-sharing OLa2Ta2 tetrahedra. The O–Ta bond length is 2.02 Å. In the eighteenth O site, O is bonded in a distorted trigonal non-coplanar geometry to three Ta atoms. The O–Ta bond length is 2.08 Å. In the nineteenth O site, O is bonded in a distorted trigonal non-coplanar geometry to three Ta atoms. In the twentieth O site, O is bonded in a distorted linear geometry to one La and two equivalent Ta atoms. In the twenty-first O site, O is bonded in a distorted linear geometry to one La and two equivalent Ta atoms. In the twenty-second O site, O is bonded in a distorted linear geometry to one La and two equivalent Ta atoms. In the twenty-third O site, O is bonded in a distorted linear geometry to one La and two equivalent Ta atoms. In the twenty-fourth O site, O is bonded in a distorted rectangular see-saw-like geometry to two La and two Ta atoms. In the twenty-fifth O site, O is bonded in a distorted rectangular see-saw-like geometry to two La and two Ta atoms. In the twenty-sixth O site, O is bonded in a linear geometry to two equivalent Ta atoms. Both O–Ta bond lengths are 1.96 Å. In the twenty-seventh O site, O is bonded in a linear geometry to two equivalent Ta atoms. Both O–Ta bond lengths are 1.95 Å. In the twenty-eighth O site, O is bonded in a linear geometry to two equivalent Ta atoms. In the twenty-ninth O site, O is bonded in a linear geometry to two equivalent Ta atoms. In the thirtieth O site, O is bonded in a distorted trigonal non-coplanar geometry to three Ta atoms. The O–Ta bond length is 2.05 Å. In the thirty-first O site, O is bonded in a distorted trigonal non-coplanar geometry to three Ta atoms. In the thirty-second O site, O is bonded in a distorted linear geometry to one La and two equivalent Ta atoms. In the thirty-third O site, O is bonded in a distorted linear geometry to one La and two equivalent Ta atoms. In the thirty-fourth O site, O is bonded in a distorted linear geometry to one La and two equivalent Ta atoms. In the thirty-fifth O site, O is bonded in a distorted linear geometry to one La and two equivalent Ta atoms. In the thirty-sixth O site, O is bonded to two La and two Ta atoms to form corner-sharing OLa2Ta2 tetrahedra. In the thirty-seventh O site, O is bonded in a bent 150 degrees geometry to two Ta atoms. In the thirty-eighth O site, O is bonded in a bent 150 degrees geometry to two Ta atoms. In the thirty-ninth O site, O is bonded in a distorted rectangular see-saw-like geometry to two La and two Ta atoms. In the fortieth O site, O is bonded in a distorted rectangular see-saw-like geometry to two La and two Ta atoms. In the forty-first O site, O is bonded in a distorted T-shaped geometry to one La and two equivalent Ta atoms. In the forty-second O site, O is bonded in a distorted linear geometry to one La and two equivalent Ta atoms.