Modulated structure of potassium sodium strontium barium niobates (KNSBN): harmonic solution

The structures of two specimens of the (K_1 - yNa_y)_2F - 2(Sr_xBa_1 - x)_2 - FNb₂O₆ family (KNSBN) have been solved and refined (x^I = 0.6, y^I = 0.45, F^I = 1.07 and x^II = 0.72, y^II = 0.45, F^II = 1.08). The KNSBN compounds appear to be incommensurately modulated, as described in a five-dimensional superspace approach with the tetragonal P4bm (pp1/2, p - p1/2) superspace group. Their modulation wavevectors are almost independent of the composition. The description of the modulation is restricted to first-order harmonics in order to limit the number of refined parameters. The modulation mainly affects the positions of the O atoms and their displacements depend on the Sr/Ba ratio. The structural models for the two compounds are not only almost identical, but also analoguous to the structural model of the Sr_xBa_1 - xNb₂O₆ parent compound: doping with K⁺ and Na⁺ cations has no significant influence on the incommensurate modulation, contrary to the strong dependence observed for the physical properties.

Computing details

For both compounds, program(s) used to refine structure: (Jana2000; Petricek and Dusek, 2000); software used to prepare material for publication: (Jana2000; Petricek and Dusek, 2000).

Figures

(I)

Crystal data

Ba0.38K0.085Na0.07Nb2O6Sr0.56	F(000) = 1740
Mr = 388	Dx = 5.283 Mg m^−3
Tetragonal, X4bm†	Mo Kα radiation, λ = 0.71069 Å
q1 = 0.31100a* + 0.31100b*; q2 = 0.31100a* + -0.31100b*	Cell parameters from 4101 reflections
a = 12.4375 (5) Å	µ = 13.79 mm^−1
c = 7.8807 (2) Å	T = 293 K
V = 1219.08 (8) Å^3	Sphere, tranparent
Z = 10	0.08 mm (radius)

† Symmetry operations: (1) x₁, x₂, x₃, x₄, x₅; (2) −x₂, x₁, x₃, x₅, −x₄; (3) 1/2−x₁, 1/2+x₂, x₃, −x₅, −x₄; (4) −x₁, −x₂, x₃, −x₄, −x₅; (5) 1/2−x₂, 1/2−x₁, x₃, −x₄, x₅; (6) x₂, −x₁, x₃, −x₅, x₄; (7) 1/2+x₁, 1/2−x₂, x₃, x₅, x₄; (8) 1/2+x₂, 1/2+x₁, x₃, x₄, −x₅; (9) x₁, x₂, 1/2+x₃, 1/2+x₄, 1/2+x₅; (10) −x₂, x₁, 1/2+x₃, 1/2+x₅, 1/2−x₄; (11) 1/2−x₁, 1/2+x₂, 1/2+x₃, 1/2−x₅, 1/2−x₄; (12) −x₁, −x₂, 1/2+x₃, 1/2−x₄, 1/2−x₅; (13) 1/2−x₂, 1/2−x₁, 1/2+x₃, 1/2−x₄, 1/2+x₅; (14) x₂, −x₁, 1/2+x₃, 1/2−x₅, 1/2+x₄; (15) 1/2+x₁, 1/2−x₂, 1/2+x₃, 1/2+x₅, 1/2+x₄; (16) 1/2+x₂, 1/2+x₁, 1/2+x₃, 1/2+x₄, 1/2−x₅.

Data collection

Nonius CCD diffractometer	7718 reflections with I > 3σ(I)
w scan, intergration method	Rint = 0.038
Absorption correction: for a sphere (Jana2000; Petricek and Dusek, 2000)	θmax = 59.6°, θmin = 3.0°
Tmin = 0.221, Tmax = 0.228	h = −27→29
144596 measured reflections	k = −30→28
8612 independent reflections	l = −18→18

Refinement

Refinement on F	Weighting scheme based on measured s.u.'s w = 1/(σ^2(F) + 0.0004F^2)
R[F^2 > 2σ(F^2)] = 0.051	(Δ/σ)max = 0.026
wR(F^2) = 0.087	Δρmax = 3.64 e Å^−3
S = 2.61	Δρmin = −5.83 e Å^−3
8612 reflections	Extinction correction: B-C type 1 Lorentzian isotropic (Becker & Coppens, 1974)
150 parameters	Extinction coefficient: 0.058 (4)

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Nb1	0	0.5	0.00125 (9)	0.00610 (5)
Nb2	0.074775 (15)	0.211720 (14)	−0.00588 (8)	0.00691 (4)
Sr1	0	0	0.23884 (11)	0.00707 (9)	0.730 (3)
O1	0.34344 (15)	0.00549 (16)	−0.0262 (4)	0.0118 (4)
O2	0.13858 (17)	0.06904 (14)	−0.0287 (3)	0.0107 (4)
O3	0.28172 (16)	0.78172 (16)	−0.0229 (4)	0.0100 (5)
O4	0	0.5	0.2307 (6)	0.0190 (8)
O5	0.29600 (16)	0.42432 (15)	0.2273 (3)	0.0126 (5)
Ba	0.17168 (2)	0.67168 (2)	0.240438	0.02187 (7)	0.403 (6)
Sr2	0.17168 (2)	0.67168 (2)	0.240438	0.02187 (7)	0.411 (7)
Na1	0	0	0.23884 (11)	0.00707 (9)	0.175
K	0.17168 (2)	0.67168 (2)	0.240438	0.02187 (7)	0.1062

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Nb1	0.00649 (8)	0.00649 (8)	0.00533 (11)	−0.00017 (8)	0	0
Nb2	0.00727 (7)	0.00625 (6)	0.00720 (7)	0.00083 (4)	0.00020 (8)	−0.00146 (8)
Sr1	0.00684 (12)	0.00684 (12)	0.0075 (2)	0	0	0
O1	0.0063 (5)	0.0148 (7)	0.0144 (9)	−0.0040 (5)	−0.0019 (8)	0.0032 (8)
O2	0.0172 (8)	0.0068 (5)	0.0081 (9)	0.0062 (5)	−0.0011 (7)	−0.0034 (6)
O3	0.0098 (5)	0.0098 (5)	0.0105 (12)	0.0032 (6)	0.0037 (7)	0.0037 (7)
O4	0.0259 (13)	0.0259 (13)	0.0052 (15)	0.0048 (15)	0	0
O5	0.0148 (8)	0.0195 (10)	0.0034 (8)	−0.0030 (7)	0.0007 (6)	−0.0014 (8)
Ba	0.02641 (11)	0.02641 (11)	0.01278 (14)	−0.01650 (14)	−0.00053 (10)	−0.00053 (10)
Sr2	0.02641 (11)	0.02641 (11)	0.01278 (14)	−0.01650 (14)	−0.00053 (10)	−0.00053 (10)
Na1	0.00684 (12)	0.00684 (12)	0.0075 (2)	0	0	0
K	0.02641 (11)	0.02641 (11)	0.01278 (14)	−0.01650 (14)	−0.00053 (10)	−0.00053 (10)

Bond lengths (Å)

	Average	Minimum	Maximum
Nb1—O1^i	1.969 (5)	1.954 (5)	1.994 (5)
Nb1—O1^ii	1.969 (5)	1.954 (5)	1.994 (5)
Nb1—O1^iii	1.969 (5)	1.954 (5)	1.995 (5)
Nb1—O1^iv	1.969 (5)	1.954 (5)	1.995 (5)
Nb1—O4	1.823 (8)	1.731 (13)	1.886 (13)
Nb1—O4^v	2.148 (8)	2.061 (13)	2.203 (13)
Nb2—O1^i	1.933 (5)	1.914 (5)	1.961 (5)
Nb2—O2	1.959 (5)	1.942 (5)	1.994 (5)
Nb2—O2^i	2.021 (5)	2.000 (5)	2.052 (5)
Nb2—O3^vi	1.994 (6)	1.971 (6)	2.024 (6)
Nb2—O5^vii	1.854 (6)	1.812 (6)	1.900 (6)
Nb2—O5^viii	2.121 (6)	2.067 (6)	2.176 (6)
Sr1—O2	2.856 (5)	2.581 (5)	3.138 (5)
Sr1—O2^ix	2.661 (5)	2.497 (5)	2.846 (5)
Sr1—O2^i	2.856 (5)	2.581 (5)	3.138 (5)
Sr1—O2^x	2.661 (5)	2.497 (5)	2.846 (5)
Sr1—O2^xi	2.856 (5)	2.581 (5)	3.138 (5)
Sr1—O2^xii	2.661 (5)	2.497 (5)	2.846 (5)
Sr1—O2^xiii	2.856 (5)	2.581 (5)	3.138 (5)
Sr1—O2^xiv	2.661 (5)	2.497 (5)	2.846 (5)
Sr1—O5^xv	2.718 (5)	2.603 (5)	2.827 (5)
Sr1—O5^vii	2.718 (5)	2.603 (5)	2.827 (5)
Sr1—O5^iv	2.718 (5)	2.603 (5)	2.827 (5)
Sr1—O5^xvi	2.718 (5)	2.603 (5)	2.827 (5)
Ba—O1^ii	2.948 (6)	2.727 (6)	3.208 (6)
Ba—O1^xvii	2.772 (6)	2.635 (6)	2.946 (6)
Ba—O1^iii	2.955 (6)	2.728 (6)	3.208 (6)
Ba—O1^xviii	2.776 (6)	2.635 (6)	2.946 (6)
Ba—O3	2.837 (5)	2.681 (6)	3.002 (6)
Ba—O3^ix	2.690 (5)	2.615 (6)	2.774 (6)
Ba—O4	3.032 (4)	2.751 (4)	3.291 (4)
Ba—O5	3.464 (5)	2.914 (5)	3.976 (5)
Ba—O5^ii	3.163 (5)	2.679 (5)	3.662 (5)
Ba—O5^iii	3.180 (5)	2.678 (5)	3.664 (5)
Ba—O5^xix	3.438 (5)	2.914 (5)	3.976 (5)
Sr2—O1^ii	2.948 (6)	2.727 (6)	3.208 (6)
Sr2—O1^xvii	2.772 (6)	2.635 (6)	2.946 (6)
Sr2—O1^iii	2.955 (6)	2.728 (6)	3.208 (6)
Sr2—O1^xviii	2.776 (6)	2.635 (6)	2.946 (6)
Sr2—O3	2.837 (5)	2.681 (6)	3.002 (6)
Sr2—O3^ix	2.690 (5)	2.615 (6)	2.774 (6)
Sr2—O4	3.032 (4)	2.751 (4)	3.291 (4)
Sr2—O5	3.464 (5)	2.914 (5)	3.976 (5)
Sr2—O5^ii	3.163 (5)	2.679 (5)	3.662 (5)
Sr2—O5^iii	3.180 (5)	2.678 (5)	3.664 (5)
Sr2—O5^xix	3.438 (5)	2.914 (5)	3.976 (5)
Na1—O2	2.856 (5)	2.581 (5)	3.138 (5)
Na1—O2^ix	2.661 (5)	2.497 (5)	2.846 (5)
Na1—O2^i	2.856 (5)	2.581 (5)	3.138 (5)
Na1—O2^x	2.661 (5)	2.497 (5)	2.846 (5)
Na1—O2^xi	2.856 (5)	2.581 (5)	3.138 (5)
Na1—O2^xii	2.661 (5)	2.497 (5)	2.846 (5)
Na1—O2^xiii	2.856 (5)	2.581 (5)	3.138 (5)
Na1—O2^xiv	2.661 (5)	2.497 (5)	2.846 (5)
Na1—O5^xv	2.718 (5)	2.603 (5)	2.827 (5)
Na1—O5^vii	2.718 (5)	2.603 (5)	2.827 (5)
Na1—O5^iv	2.718 (5)	2.603 (5)	2.827 (5)
Na1—O5^xvi	2.718 (5)	2.603 (5)	2.827 (5)
K—O1^ii	2.948 (6)	2.727 (6)	3.208 (6)
K—O1^xvii	2.772 (6)	2.635 (6)	2.946 (6)
K—O1^iii	2.955 (6)	2.728 (6)	3.208 (6)
K—O1^xviii	2.776 (6)	2.635 (6)	2.946 (6)
K—O3	2.837 (5)	2.681 (6)	3.002 (6)
K—O3^ix	2.690 (5)	2.615 (6)	2.774 (6)
K—O4	3.032 (4)	2.751 (4)	3.291 (4)
K—O5	3.464 (5)	2.914 (5)	3.976 (5)
K—O5^ii	3.163 (5)	2.679 (5)	3.662 (5)
K—O5^iii	3.180 (5)	2.678 (5)	3.664 (5)
K—O5^xix	3.438 (5)	2.914 (5)	3.976 (5)

Symmetry codes: (i) −x₂, x₁, x₃, x₅, −x₄; (ii) −x₁+1/2, x₂+1/2, x₃, −x₅, −x₄; (iii) x₂, −x₁+1, x₃, −x₅, x₄; (iv) x₁−1/2, −x₂+1/2, x₃, x₅, x₄; (v) x₁, x₂, x₃−1/2, x₁/2, x₁/2; (vi) −x₂+1, x₁, x₃, x₅, −x₄; (vii) −x₂+1/2, −x₁+1/2, x₃, −x₄, x₅; (viii) −x₂+1/2, −x₁+1/2, x₃−1/2, −x₁/2, x₁/2; (ix) x₁, x₂, x₃+1/2, x₁/2, x₁/2; (x) −x₂, x₁, x₃+1/2, x₁/2, −x₁/2; (xi) −x₁, −x₂, x₃, −x₄, −x₅; (xii) −x₁, −x₂, x₃+1/2, −x₁/2, −x₁/2; (xiii) x₂, −x₁, x₃, −x₅, x₄; (xiv) x₂, −x₁, x₃+1/2, −x₁/2, x₁/2; (xv) −x₁+1/2, x₂−1/2, x₃, −x₅, −x₄; (xvi) x₂−1/2, x₁−1/2, x₃, x₄, −x₅; (xvii) −x₁+1/2, x₂+1/2, x₃+1/2, −x₁/2, −x₁/2; (xviii) x₂, −x₁+1, x₃+1/2, −x₁/2, x₁/2; (xix) x₂−1/2, x₁+1/2, x₃, x₄, −x₅.

(KNSBN72)

Crystal data

Ba0.26K0.09Na0.08Nb2O6Sr0.67	F(000) = 1719
Mr = 381.6	Dx = 5.221 Mg m^−3
Tetragonal, X4bm†	Mo Kα radiation, λ = 0.71069 Å
q1 = 0.30720a* + 0.30720b*; q2 = 0.30720a* + -0.30720b*	Cell parameters from 2000 reflections
a = 12.4292 (8) Å	µ = 14.11 mm^−1
c = 7.8524 (3) Å	T = 293 K
V = 1213.08 (12) Å^3	Sphere, transparent
Z = 10	0.12 mm (radius)

† Symmetry operations: (1) x₁, x₂, x₃, x₄, x₅; (2) −x₂, x₁, x₃, x₅, −x₄; (3) 1/2−x₁, 1/2+x₂, x₃, −x₅, −x₄; (4) −x₁, −x₂, x₃, −x₄, −x₅; (5) 1/2−x₂, 1/2−x₁, x₃, −x₄, x₅; (6) x₂, −x₁, x₃, −x₅, x₄; (7) 1/2+x₁, 1/2−x₂, x₃, x₅, x₄; (8) 1/2+x₂, 1/2+x₁, x₃, x₄, −x₅; (9) x₁, x₂, 1/2+x₃, 1/2+x₄, 1/2+x₅; (10) −x₂, x₁, 1/2+x₃, 1/2+x₅, 1/2−x₄; (11) 1/2−x₁, 1/2+x₂, 1/2+x₃, 1/2−x₅, 1/2−x₄; (12) −x₁, −x₂, 1/2+x₃, 1/2−x₄, 1/2−x₅; (13) 1/2−x₂, 1/2−x₁, 1/2+x₃, 1/2−x₄, 1/2+x₅; (14) x₂, −x₁, 1/2+x₃, 1/2−x₅, 1/2+x₄; (15) 1/2+x₁, 1/2−x₂, 1/2+x₃, 1/2+x₅, 1/2+x₄; (16) 1/2+x₂, 1/2+x₁, 1/2+x₃, 1/2+x₄, 1/2−x₅.

Data collection

Nonius CCD diffractometer	6196 reflections with I > 3σ(I)
w scan, intergration method	Rint = 0.038
Absorption correction: for a sphere (Jana2000; Petricek and Dusek, 2000)	θmax = 40.5°, θmin = 3.3°
Tmin = 0.106, Tmax = 0.152	h = −22→22
96783 measured reflections	k = −22→19
7577 independent reflections	l = −14→14

Refinement

Refinement on F	Weighting scheme based on measured s.u.'s w = 1/(σ^2(F) + 0.0004F^2)
R[F^2 > 2σ(F^2)] = 0.055	(Δ/σ)max = 0.006
wR(F^2) = 0.074	Δρmax = 3.07 e Å^−3
S = 2.32	Δρmin = −5.07 e Å^−3
6196 reflections	Extinction correction: B-C type 1 Lorentzian isotropic (Becker & Coppens, 1974)
129 parameters	Extinction coefficient: 0.069 (3)

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Nb1	0	0.5	0.00128 (12)	0.00738 (8)
Nb2	0.074907 (18)	0.211795 (17)	−0.00681 (10)	0.00831 (6)
Sr1	0	0	0.23820 (13)	0.00745 (13)	0.712 (4)
O1	0.34394 (15)	0.00525 (14)	−0.0263 (3)	0.0090 (3)*
O2	0.13855 (16)	0.06807 (15)	−0.0286 (3)	0.0106 (3)*
O3	0.28142 (15)	0.78142 (15)	−0.0207 (4)	0.0093 (4)*
O4	0	0.5	0.2334 (7)	0.0184 (8)*
O5	0.29630 (13)	0.42457 (15)	0.2277 (3)	0.0091 (4)*
Ba	0.17129 (3)	0.67129 (3)	0.240438	0.02574 (9)	0.247 (8)
Sr2	0.17129 (3)	0.67129 (3)	0.240438	0.02574 (9)	0.560 (8)
Na1	0	0	0.23820 (13)	0.00745 (13)	0.1975
K	0.17129 (3)	0.67129 (3)	0.240438	0.02574 (9)	0.12

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Nb1	0.00770 (11)	0.00770 (11)	0.00672 (17)	−0.00021 (11)	0	0
Nb2	0.00844 (10)	0.00717 (10)	0.00933 (12)	0.00080 (5)	0.00013 (11)	−0.00158 (11)
Sr1	0.00702 (18)	0.00702 (18)	0.0083 (3)	0	0	0
Ba	0.03204 (13)	0.03204 (13)	0.0131 (2)	−0.0214 (2)	0.00100 (15)	0.00100 (15)
Sr2	0.03204 (13)	0.03204 (13)	0.0131 (2)	−0.0214 (2)	0.00100 (15)	0.00100 (15)
Na1	0.00702 (18)	0.00702 (18)	0.0083 (3)	0	0	0
K	0.03204 (13)	0.03204 (13)	0.0131 (2)	−0.0214 (2)	0.00100 (15)	0.00100 (15)

Bond lengths (Å)

	Average	Minimum	Maximum
Nb1—O1^i	1.968 (5)	1.923 (5)	2.018 (5)
Nb1—O1^ii	1.968 (5)	1.923 (5)	2.018 (5)
Nb1—O1^iii	1.967 (5)	1.923 (5)	2.018 (5)
Nb1—O1^iv	1.967 (5)	1.923 (5)	2.018 (5)
Nb1—O4	1.842 (9)	1.734 (14)	1.911 (13)
Nb1—O4^v	2.127 (9)	2.024 (14)	2.187 (10)
Nb2—O1^i	1.940 (5)	1.887 (5)	2.000 (5)
Nb2—O2	1.972 (5)	1.943 (5)	2.011 (5)
Nb2—O2^i	2.013 (5)	1.971 (5)	2.051 (5)
Nb2—O3^vi	1.995 (5)	1.944 (5)	2.050 (5)
Nb2—O5^vii	1.863 (6)	1.805 (6)	1.915 (6)
Nb2—O5^viii	2.110 (6)	2.055 (6)	2.174 (6)
Sr1—O2	2.843 (5)	2.533 (5)	3.165 (5)
Sr1—O2^ix	2.656 (5)	2.433 (5)	2.906 (5)
Sr1—O2^i	2.843 (5)	2.533 (5)	3.165 (5)
Sr1—O2^x	2.656 (5)	2.433 (5)	2.906 (5)
Sr1—O2^xi	2.843 (5)	2.533 (5)	3.165 (5)
Sr1—O2^xii	2.656 (5)	2.433 (5)	2.906 (5)
Sr1—O2^xiii	2.843 (5)	2.533 (5)	3.165 (5)
Sr1—O2^xiv	2.656 (5)	2.433 (5)	2.906 (5)
Sr1—O5^xv	2.718 (4)	2.573 (4)	2.841 (4)
Sr1—O5^vii	2.718 (4)	2.573 (4)	2.841 (4)
Sr1—O5^iv	2.718 (4)	2.573 (4)	2.841 (4)
Sr1—O5^xvi	2.718 (4)	2.573 (4)	2.841 (4)
Ba—O1^ii	2.940 (5)	2.643 (5)	3.299 (5)
Ba—O1^xvii	2.768 (5)	2.604 (5)	2.976 (5)
Ba—O1^iii	2.949 (5)	2.643 (5)	3.299 (5)
Ba—O1^xviii	2.772 (5)	2.604 (5)	2.976 (5)
Ba—O3	2.820 (5)	2.622 (6)	3.039 (6)
Ba—O3^ix	2.699 (5)	2.578 (5)	2.835 (6)
Ba—O4	3.025 (4)	2.657 (4)	3.366 (4)
Ba—O5	3.462 (5)	2.775 (5)	4.105 (5)
Ba—O5^ii	3.167 (5)	2.550 (5)	3.804 (5)
Ba—O5^iii	3.188 (5)	2.549 (5)	3.805 (5)
Ba—O5^xix	3.430 (5)	2.774 (5)	4.105 (5)
Sr2—O1^ii	2.940 (5)	2.643 (5)	3.299 (5)
Sr2—O1^xvii	2.768 (5)	2.604 (5)	2.976 (5)
Sr2—O1^iii	2.949 (5)	2.643 (5)	3.299 (5)
Sr2—O1^xviii	2.772 (5)	2.604 (5)	2.976 (5)
Sr2—O3	2.820 (5)	2.622 (6)	3.039 (6)
Sr2—O3^ix	2.699 (5)	2.578 (5)	2.835 (6)
Sr2—O4	3.025 (4)	2.657 (4)	3.366 (4)
Sr2—O5	3.462 (5)	2.775 (5)	4.105 (5)
Sr2—O5^ii	3.167 (5)	2.550 (5)	3.804 (5)
Sr2—O5^iii	3.188 (5)	2.549 (5)	3.805 (5)
Sr2—O5^xix	3.430 (5)	2.774 (5)	4.105 (5)
Na1—O2	2.843 (5)	2.533 (5)	3.165 (5)
Na1—O2^ix	2.656 (5)	2.433 (5)	2.906 (5)
Na1—O2^i	2.843 (5)	2.533 (5)	3.165 (5)
Na1—O2^x	2.656 (5)	2.433 (5)	2.906 (5)
Na1—O2^xi	2.843 (5)	2.533 (5)	3.165 (5)
Na1—O2^xii	2.656 (5)	2.433 (5)	2.906 (5)
Na1—O2^xiii	2.843 (5)	2.533 (5)	3.165 (5)
Na1—O2^xiv	2.656 (5)	2.433 (5)	2.906 (5)
Na1—O5^xv	2.718 (4)	2.573 (4)	2.841 (4)
Na1—O5^vii	2.718 (4)	2.573 (4)	2.841 (4)
Na1—O5^iv	2.718 (4)	2.573 (4)	2.841 (4)
Na1—O5^xvi	2.718 (4)	2.573 (4)	2.841 (4)
K—O1^ii	2.940 (5)	2.643 (5)	3.299 (5)
K—O1^xvii	2.768 (5)	2.604 (5)	2.976 (5)
K—O1^iii	2.949 (5)	2.643 (5)	3.299 (5)
K—O1^xviii	2.772 (5)	2.604 (5)	2.976 (5)
K—O3	2.820 (5)	2.622 (6)	3.039 (6)
K—O3^ix	2.699 (5)	2.578 (5)	2.835 (6)
K—O4	3.025 (4)	2.657 (4)	3.366 (4)
K—O5	3.462 (5)	2.775 (5)	4.105 (5)
K—O5^ii	3.167 (5)	2.550 (5)	3.804 (5)
K—O5^iii	3.188 (5)	2.549 (5)	3.805 (5)
K—O5^xix	3.430 (5)	2.774 (5)	4.105 (5)

Symmetry codes: (i) −x₂, x₁, x₃, x₅, −x₄; (ii) −x₁+1/2, x₂+1/2, x₃, −x₅, −x₄; (iii) x₂, −x₁+1, x₃, −x₅, x₄; (iv) x₁−1/2, −x₂+1/2, x₃, x₅, x₄; (v) x₁, x₂, x₃−1/2, x₁/2, x₁/2; (vi) −x₂+1, x₁, x₃, x₅, −x₄; (vii) −x₂+1/2, −x₁+1/2, x₃, −x₄, x₅; (viii) −x₂+1/2, −x₁+1/2, x₃−1/2, −x₁/2, x₁/2; (ix) x₁, x₂, x₃+1/2, x₁/2, x₁/2; (x) −x₂, x₁, x₃+1/2, x₁/2, −x₁/2; (xi) −x₁, −x₂, x₃, −x₄, −x₅; (xii) −x₁, −x₂, x₃+1/2, −x₁/2, −x₁/2; (xiii) x₂, −x₁, x₃, −x₅, x₄; (xiv) x₂, −x₁, x₃+1/2, −x₁/2, x₁/2; (xv) −x₁+1/2, x₂−1/2, x₃, −x₅, −x₄; (xvi) x₂−1/2, x₁−1/2, x₃, x₄, −x₅; (xvii) −x₁+1/2, x₂+1/2, x₃+1/2, −x₁/2, −x₁/2; (xviii) x₂, −x₁+1, x₃+1/2, −x₁/2, x₁/2; (xix) x₂−1/2, x₁+1/2, x₃, x₄, −x₅.