KEr3F10 crystallizes in the orthorhombic Immm space group. K(1) is bonded in a distorted tetrahedral geometry to two equivalent F(4) and two equivalent F(5) atoms. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a 8-coordinate geometry to one F(2), one F(3), two equivalent F(1), two equivalent F(4), and two equivalent F(5) atoms. In the second Er site, Er(2) is bonded in a 8-coordinate geometry to two equivalent F(4), two equivalent F(5), and four equivalent F(1) atoms. There are five inequivalent F sites. In the first F site, F(1) is bonded in a bent 150 degrees geometry to one Er(1) and one Er(2) atom. In the second F site, F(2) is bonded in a bent 150 degrees geometry to two equivalent Er(1) atoms. In the third F site, F(3) is bonded in a bent 150 degrees geometry to two equivalent Er(1) atoms. In the fourth F site, F(4) is bonded to one K(1), one Er(2), and two equivalent Er(1) atoms to form a mixture of edge and corner-sharing FKEr3 tetrahedra. In the fifth F site, F(5) is bonded to one K(1), one Er(2), and two equivalent Er(1) atoms to form a mixture of edge and corner-sharing FKEr3 tetrahedra.
KEr3F10 crystallizes in the orthorhombic Immm space group. K(1) is bonded in a distorted tetrahedral geometry to two equivalent F(4) and two equivalent F(5) atoms. Both K(1)-F(4) bond lengths are 2.72 Å. Both K(1)-F(5) bond lengths are 2.72 Å. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a 8-coordinate geometry to one F(2), one F(3), two equivalent F(1), two equivalent F(4), and two equivalent F(5) atoms. The Er(1)-F(2) bond length is 2.17 Å. The Er(1)-F(3) bond length is 2.17 Å. Both Er(1)-F(1) bond lengths are 2.17 Å. Both Er(1)-F(4) bond lengths are 2.32 Å. Both Er(1)-F(5) bond lengths are 2.32 Å. In the second Er site, Er(2) is bonded in a 8-coordinate geometry to two equivalent F(4), two equivalent F(5), and four equivalent F(1) atoms. Both Er(2)-F(4) bond lengths are 2.32 Å. Both Er(2)-F(5) bond lengths are 2.32 Å. All Er(2)-F(1) bond lengths are 2.17 Å. There are five inequivalent F sites. In the first F site, F(1) is bonded in a bent 150 degrees geometry to one Er(1) and one Er(2) atom. In the second F site, F(2) is bonded in a bent 150 degrees geometry to two equivalent Er(1) atoms. In the third F site, F(3) is bonded in a bent 150 degrees geometry to two equivalent Er(1) atoms. In the fourth F site, F(4) is bonded to one K(1), one Er(2), and two equivalent Er(1) atoms to form a mixture of edge and corner-sharing FKEr3 tetrahedra. In the fifth F site, F(5) is bonded to one K(1), one Er(2), and two equivalent Er(1) atoms to form a mixture of edge and corner-sharing FKEr3 tetrahedra.