Materials Data on K4Eu2U(GeO4)4 by Materials Project

Abstract

K4UEu2(GeO4)4 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of K–O bond distances ranging from 2.79–3.06 Å. In the second K1+ site, K1+ is bonded to seven O2- atoms to form distorted KO7 pentagonal bipyramids that share corners with two equivalent UO6 octahedra, corners with four GeO4 tetrahedra, edges with three equivalent KO7 pentagonal bipyramids, edges with two GeO4 tetrahedra, and a faceface with one UO6 octahedra. The corner-sharing octahedra tilt angles range from 59–62°. There are a spread of K–O bond distances ranging from 2.89–3.11 Å. U6+ is bonded to six O2- atoms to form UO6 octahedra that share corners with four equivalent KO7 pentagonal bipyramids, corners with four GeO4 tetrahedra, and faces with two equivalent KO7 pentagonal bipyramids. There are a spread of U–O bond distances ranging from 1.89–2.25 Å. Eu3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Eu–O bond distances ranging from 2.30–2.66 Å. There are two inequivalent Ge4+ sites. In the first Ge4+ site, Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share a cornercorner with one UO6 octahedra, corners with two equivalent KO7 pentagonal bipyramids, a cornercorner with one GeO4 tetrahedra, and an edgeedge with one KO7 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 47°. There are a spread of Ge–O bond distances ranging from 1.74–1.83 Å. In the second Ge4+ site, Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share a cornercorner with one UO6 octahedra, corners with two equivalent KO7 pentagonal bipyramids, a cornercorner with one GeO4 tetrahedra, and an edgeedge with one KO7 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 48°. There are a spread of Ge–O bond distances ranging from 1.76–1.82 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent K1+, one U6+, and one Ge4+ atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent K1+, one Eu3+, and one Ge4+ atom. In the third O2- site, O2- is bonded to two equivalent K1+, one Eu3+, and one Ge4+ atom to form distorted edge-sharing OK2EuGe trigonal pyramids. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to three K1+ and two Ge4+ atoms. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to one K1+, two equivalent Eu3+, and one Ge4+ atom. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to one K1+, two equivalent Eu3+, and one Ge4+ atom. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent K1+, one U6+, and one Ge4+ atom. In the eighth O2- site, O2- is bonded in a distorted single-bond geometry to one K1+, one U6+, and one Eu3+ atom.