K2HfO6 crystallizes in the orthorhombic Cmme space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. In the second K site, K(2) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(5), and four equivalent O(4) atoms. There are two inequivalent Hf sites. In the first Hf site, Hf(1) is bonded in an octahedral geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. In the second Hf site, Hf(2) is bonded in an octahedral geometry to two equivalent O(5) and four equivalent O(4) atoms. There are five inequivalent O sites. In the first O site, O(3) is bonded in a distorted T-shaped geometry to two equivalent K(1) and one Hf(1) atom. In the second O site, O(4) is bonded in a 1-coordinate geometry to one K(1), two equivalent K(2), and one Hf(2) atom. In the third O site, O(5) is bonded in a distorted T-shaped geometry to two equivalent K(2) and one Hf(2) atom. In the fourth O site, O(1) is bonded in a single-bond geometry to two equivalent K(1) and one Hf(1) atom. In the fifth O site, O(2) is bonded in a 5-coordinate geometry to two equivalent K(1), two equivalent K(2), and one Hf(1) atom.
K2HfO6 crystallizes in the orthorhombic Cmme space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. Both K(1)-O(1) bond lengths are 3.21 Å. Both K(1)-O(2) bond lengths are 3.08 Å. There is one shorter (2.84 Å) and one longer (2.97 Å) K(1)-O(3) bond length. Both K(1)-O(4) bond lengths are 2.79 Å. In the second K site, K(2) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(5), and four equivalent O(4) atoms. Both K(2)-O(2) bond lengths are 2.72 Å. Both K(2)-O(5) bond lengths are 2.90 Å. There are two shorter (2.88 Å) and two longer (3.25 Å) K(2)-O(4) bond lengths. There are two inequivalent Hf sites. In the first Hf site, Hf(1) is bonded in an octahedral geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. Both Hf(1)-O(1) bond lengths are 2.09 Å. Both Hf(1)-O(2) bond lengths are 2.01 Å. Both Hf(1)-O(3) bond lengths are 2.08 Å. In the second Hf site, Hf(2) is bonded in an octahedral geometry to two equivalent O(5) and four equivalent O(4) atoms. Both Hf(2)-O(5) bond lengths are 2.05 Å. All Hf(2)-O(4) bond lengths are 2.05 Å. There are five inequivalent O sites. In the first O site, O(3) is bonded in a distorted T-shaped geometry to two equivalent K(1) and one Hf(1) atom. In the second O site, O(4) is bonded in a 1-coordinate geometry to one K(1), two equivalent K(2), and one Hf(2) atom. In the third O site, O(5) is bonded in a distorted T-shaped geometry to two equivalent K(2) and one Hf(2) atom. In the fourth O site, O(1) is bonded in a single-bond geometry to two equivalent K(1) and one Hf(1) atom. In the fifth O site, O(2) is bonded in a 5-coordinate geometry to two equivalent K(1), two equivalent K(2), and one Hf(1) atom.