K2NaNbO2F4 is (Cubic) Perovskite-derived structured and crystallizes in the monoclinic P2_1 space group. There are two inequivalent K sites. In the first K site, K(1) is bonded to two equivalent O(1), two equivalent O(2), two equivalent F(1), two equivalent F(4), and four equivalent F(3) atoms to form KO4F8 cuboctahedra that share corners with four equivalent K(1)O4F8 cuboctahedra, corners with eight equivalent K(2)O4F8 cuboctahedra, faces with two equivalent K(2)O4F8 cuboctahedra, faces with four equivalent K(1)O4F8 cuboctahedra, faces with four equivalent Na(1)O2F4 octahedra, and faces with four equivalent Nb(1)O2F4 octahedra. In the second K site, K(2) is bonded to two equivalent O(1), two equivalent O(2), two equivalent F(1), two equivalent F(4), and four equivalent F(2) atoms to form KO4F8 cuboctahedra that share corners with four equivalent K(2)O4F8 cuboctahedra, corners with eight equivalent K(1)O4F8 cuboctahedra, faces with two equivalent K(1)O4F8 cuboctahedra, faces with four equivalent K(2)O4F8 cuboctahedra, faces with four equivalent Na(1)O2F4 octahedra, and faces with four equivalent Nb(1)O2F4 octahedra. Na(1) is bonded to one O(1), one O(2), one F(1), one F(2), one F(3), and one F(4) atom to form NaO2F4 octahedra that share corners with six equivalent Nb(1)O2F4 octahedra, faces with four equivalent K(1)O4F8 cuboctahedra, and faces with four equivalent K(2)O4F8 cuboctahedra. The corner-sharing octahedral tilt angles range from 1-3°. Nb(1) is bonded to one O(1), one O(2), one F(1), one F(2), one F(3), and one F(4) atom to form NbO2F4 octahedra that share corners with six equivalent Na(1)O2F4 octahedra, faces with four equivalent K(1)O4F8 cuboctahedra, and faces with four equivalent K(2)O4F8 cuboctahedra. The corner-sharing octahedral tilt angles range from 1-3°. There are two inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to two equivalent K(1), two equivalent K(2), one Na(1), and one Nb(1) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to two equivalent K(1), two equivalent K(2), one Na(1), and one Nb(1) atom. There are four inequivalent F sites. In the first F site, F(1) is bonded in a distorted linear geometry to two equivalent K(1), two equivalent K(2), one Na(1), and one Nb(1) atom. In the second F site, F(2) is bonded in a distorted linear geometry to four equivalent K(2), one Na(1), and one Nb(1) atom. In the third F site, F(3) is bonded in a distorted linear geometry to four equivalent K(1), one Na(1), and one Nb(1) atom. In the fourth F site, F(4) is bonded in a distorted linear geometry to two equivalent K(1), two equivalent K(2), one Na(1), and one Nb(1) atom.
K2NaNbO2F4 is (Cubic) Perovskite-derived structured and crystallizes in the monoclinic P2_1 space group. There are two inequivalent K sites. In the first K site, K(1) is bonded to two equivalent O(1), two equivalent O(2), two equivalent F(1), two equivalent F(4), and four equivalent F(3) atoms to form KO4F8 cuboctahedra that share corners with four equivalent K(1)O4F8 cuboctahedra, corners with eight equivalent K(2)O4F8 cuboctahedra, faces with two equivalent K(2)O4F8 cuboctahedra, faces with four equivalent K(1)O4F8 cuboctahedra, faces with four equivalent Na(1)O2F4 octahedra, and faces with four equivalent Nb(1)O2F4 octahedra. There is one shorter (3.01 Å) and one longer (3.07 Å) K(1)-O(1) bond length. There is one shorter (3.02 Å) and one longer (3.07 Å) K(1)-O(2) bond length. There is one shorter (3.00 Å) and one longer (3.06 Å) K(1)-F(1) bond length. There is one shorter (3.02 Å) and one longer (3.05 Å) K(1)-F(4) bond length. There are a spread of K(1)-F(3) bond distances ranging from 3.02-3.07 Å. In the second K site, K(2) is bonded to two equivalent O(1), two equivalent O(2), two equivalent F(1), two equivalent F(4), and four equivalent F(2) atoms to form KO4F8 cuboctahedra that share corners with four equivalent K(2)O4F8 cuboctahedra, corners with eight equivalent K(1)O4F8 cuboctahedra, faces with two equivalent K(1)O4F8 cuboctahedra, faces with four equivalent K(2)O4F8 cuboctahedra, faces with four equivalent Na(1)O2F4 octahedra, and faces with four equivalent Nb(1)O2F4 octahedra. There is one shorter (3.06 Å) and one longer (3.11 Å) K(2)-O(1) bond length. There is one shorter (3.01 Å) and one longer (3.10 Å) K(2)-O(2) bond length. There is one shorter (3.03 Å) and one longer (3.08 Å) K(2)-F(1) bond length. There is one shorter (3.04 Å) and one longer (3.11 Å) K(2)-F(4) bond length. There are a spread of K(2)-F(2) bond distances ranging from 3.01-3.08 Å. Na(1) is bonded to one O(1), one O(2), one F(1), one F(2), one F(3), and one F(4) atom to form NaO2F4 octahedra that share corners with six equivalent Nb(1)O2F4 octahedra, faces with four equivalent K(1)O4F8 cuboctahedra, and faces with four equivalent K(2)O4F8 cuboctahedra. The corner-sharing octahedral tilt angles range from 1-3°. The Na(1)-O(1) bond length is 2.40 Å. The Na(1)-O(2) bond length is 2.40 Å. The Na(1)-F(1) bond length is 2.28 Å. The Na(1)-F(2) bond length is 2.29 Å. The Na(1)-F(3) bond length is 2.28 Å. The Na(1)-F(4) bond length is 2.26 Å. Nb(1) is bonded to one O(1), one O(2), one F(1), one F(2), one F(3), and one F(4) atom to form NbO2F4 octahedra that share corners with six equivalent Na(1)O2F4 octahedra, faces with four equivalent K(1)O4F8 cuboctahedra, and faces with four equivalent K(2)O4F8 cuboctahedra. The corner-sharing octahedral tilt angles range from 1-3°. The Nb(1)-O(1) bond length is 1.90 Å. The Nb(1)-O(2) bond length is 1.90 Å. The Nb(1)-F(1) bond length is 2.02 Å. The Nb(1)-F(2) bond length is 2.03 Å. The Nb(1)-F(3) bond length is 2.04 Å. The Nb(1)-F(4) bond length is 2.03 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to two equivalent K(1), two equivalent K(2), one Na(1), and one Nb(1) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to two equivalent K(1), two equivalent K(2), one Na(1), and one Nb(1) atom. There are four inequivalent F sites. In the first F site, F(1) is bonded in a distorted linear geometry to two equivalent K(1), two equivalent K(2), one Na(1), and one Nb(1) atom. In the second F site, F(2) is bonded in a distorted linear geometry to four equivalent K(2), one Na(1), and one Nb(1) atom. In the third F site, F(3) is bonded in a distorted linear geometry to four equivalent K(1), one Na(1), and one Nb(1) atom. In the fourth F site, F(4) is bonded in a distorted linear geometry to two equivalent K(1), two equivalent K(2), one Na(1), and one Nb(1) atom.