Dynamic orientational disorder in crystals of fluoroelpasolites, structural refinement of (NH₄)₃AlF₆, (NH₄)₃TiOF₅ and Rb₂KTiOF₅

Room-temperature crystal structures of triammonium hexafluoroaluminate, (NH₄)₃AlF₆ (I), and triammonium oxopentafluorotitanate, (NH₄)₃TiOF₅ (II), were refined, and the crystal structures of dirubidium potassium oxopentaflourotitanate, Rb₂KTiOF₅, at 297 K (III) and 218 K (IV) were determined using single-crystal X-ray diffraction techniques. In ammonium fluoroelpasolites [(I) and (II)], the ligand (O, F) atoms are located in the mixed 24e + 96j position of the Fm3m unit cell. The 24e position is occupied by the ligand atoms predominantly in (III) and fully in (IV). `Ordered' N1 and Rb atoms are tetrahedrally displaced from the 8c position into the 32f site, and the H atoms of the disordered ammonium group N2 are statistically distributed in the 96k and 32f positions. The Ti atoms in (II) and (IV) are shifted from the 4a position to 24e thus allowing identification of the O and F atoms in the octahedron on a local scale. The disorder in the crystals is of a dynamic nature. Unique Raman spectra of Rb₂KTiOF₅ under the laser beam of 1064 nm indicate fast octahedral reorientations resulting in physical equalizations of the Ti-O and Ti-F distances as well as in the appearance of totally synchronous Ti-O and Ti-F stretching vibrations at 750 cm^-1. This phenomenon is assumed to also take place under X-rays.

Computing details

For all compounds, data collection: Bruker Smart v5.054 (Bruker, 1998); cell refinement: Bruker SAINT v6.02a (Bruker, 2000); data reduction: Bruker SAINT v6.02a (Bruker, 2000); program(s) used to solve structure: Bruker SHELXTL v5.1 (Bruker, 1998); program(s) used to refine structure: Bruker SHELXTL v5.1 (Bruker, 1998); molecular graphics: Bruker SHELXTL v5.1 (Bruker, 1998); software used to prepare material for publication: Bruker SHELXTL v5.1 (Bruker, 1998).

Figures

(I) ammonium hexafluoroaluminate

Crystal data

H12N3AlF6)	Dx = 1.815 Mg m^−3
Mr = 195.11	Mo Kα radiation, λ = 0.71073 Å
Cubic, Fm3m	Cell parameters from 512 reflections
Hall symbol: -F 4 2 3	θ = 3.2–38.8°
a = 8.9378 (2) Å	µ = 0.34 mm^−1
V = 713.99 (3) Å^3	T = 297 K
Z = 4	Sphere, colorless
F(000) = 400	0.30 × 0.30 × 0.30 mm

Data collection

Bruker P4 diffractometer	138 independent reflections
Radiation source: fine-focus sealed tube	137 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.016
Detector resolution: 8.33 pixels mm^-1	θmax = 38.8°, θmin = 4.0°
ω scans	h = −15→14
Absorption correction: multi-scan SADABS v.2.03; Bruker 1999	k = −15→15
Tmin = 0.905, Tmax = 0.905	l = −15→15
4547 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.028	Hydrogen site location: difference Fourier map
wR(F^2) = 0.077	H-atom parameters not refined
S = 1.09	w = 1/[σ^2(Fo^2) + (0.0389P)^2 + 0.5425P] where P = (Fo^2 + 2Fc^2)/3
137 reflections	(Δ/σ)max = 0.047
15 parameters	Δρmax = 0.24 e Å^−3
0 restraints	Δρmin = −0.37 e Å^−3

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

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

	x	y	z	Uiso*/Ueq	Occ. (<1)
Al1	0.0000	0.0000	0.0000	0.01748 (12)
N1	0.2594 (3)	0.2594 (3)	0.2594 (3)	0.0307 (5)	0.25
N2	0.5000	0.5000	0.5000	0.0529 (8)
F1	0.0000	0.0000	0.1971 (3)	0.0803 (15)	0.33
F2	0.0000	0.0525 (4)	0.1925 (3)	0.0663 (11)	0.17
H11	0.2034	0.2034	0.2034	0.086*	0.25
H12	0.3154	0.3154	0.2034	0.086*	0.08
H13	0.3154	0.2034	0.3154	0.086*	0.08
H14	0.2034	0.3154	0.3154	0.086*	0.08
H2	0.5960	0.5192	0.5192	0.065*	0.13
H3	0.4430	0.4430	0.4430	0.065*	0.12

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Al1	0.01748 (12)	0.01748 (12)	0.01748 (12)	0.000	0.000	0.000
N1	0.0307 (5)	0.0307 (5)	0.0307 (5)	0.0028 (8)	0.0028 (8)	0.0028 (8)
N2	0.0529 (8)	0.0529 (8)	0.0529 (8)	0.000	0.000	0.000
F1	0.115 (2)	0.115 (2)	0.0102 (8)	0.000	0.000	0.000
F2	0.085 (2)	0.085 (2)	0.0296 (9)	0.000	0.000	−0.0258 (10)

Geometric parameters (Å, º)

Al1—F1	1.762 (3)	N2—F1^xii	2.707 (3)
Al1—F1^i	1.762 (3)	N2—F1^xv	2.707 (3)
Al1—F2^ii	1.784 (3)	N2—F2^ix	2.788 (3)
Al1—F2^iii	1.784 (3)	N2—F2^xvi	2.788 (3)
Al1—F2^iv	1.784 (3)	N2—F2^xvii	2.788 (3)
Al1—F2^v	1.784 (3)	N2—F2^vii	2.788 (3)
N1—N1^vi	0.238 (7)	F1—F2^ii	2.507 (2)
N1—N1^vii	0.238 (7)	F1—F2^xviii	2.507 (2)
N1—N1^viii	0.238 (7)	F1—F2^xix	2.507 (2)
N1—F2^ix	2.794 (4)	F1—F2^xx	2.507 (2)
N1—F2^x	2.869 (2)	F1—F2^xxi	2.507 (2)
N1—F2^xi	2.896 (2)	F1—F2^xxii	2.507 (2)
N1—F2^i	3.025 (4)	F1—F2^xxiii	2.507 (2)
N1—F1^xii	3.092 (3)	F1—F2^xxiv	2.507 (2)
N1—F1^xiii	3.1860 (4)	F2—F2^xxv	2.523 (4)
N1—F1^xiv	3.1860 (4)	F2—F2^xxvi	2.523 (4)
N1—F1	3.326 (4)
F1^xxvii—Al1—F1^i	180.0	F1^iv—Al1—F2^xviii	90.0
F1^iv—Al1—F2^ii	90.0	F1—Al1—F2^xviii	90.0
F1—Al1—F2^ii	90.0	F1^xviii—Al1—F2^xxvii	90.0
F1^i—Al1—F2^iii	90.0	F1^xxiv—Al1—F2^xxvii	90.0
F1^xxvii—Al1—F2^iv	90.0	N1^vi—N1—N1^vii	60.001 (10)
F1^i—Al1—F2^iv	90.0	N1^vi—N1—N1^viii	60.001 (9)
F1^xviii—Al1—F2^v	90.0	N1^vii—N1—N1^viii	59.998 (9)
F1^xxiv—Al1—F2^v	90.0

Symmetry codes: (i) z, x, y; (ii) −z, −y, x; (iii) x, −z, −y; (iv) −x, −y, −z; (v) −y, −x, −z; (vi) x, −y+1/2, −z+1/2; (vii) −x+1/2, −y+1/2, z; (viii) −x+1/2, y, −z+1/2; (ix) z, −y+1/2, x+1/2; (x) −z+1/2, y, −x+1/2; (xi) −z+1/2, −y+1/2, x; (xii) y+1/2, z, x+1/2; (xiii) −y+1/2, −z+1/2, −x; (xiv) −y, −z+1/2, −x+1/2; (xv) x+1/2, y+1/2, z; (xvi) x+1/2, z, −y+1/2; (xvii) −y+1/2, −x+1/2, z; (xviii) −y, −z, −x; (xix) −z, y, −x; (xx) y, −z, x; (xxi) z, −y, x; (xxii) z, y, −x; (xxiii) −y, z, −x; (xxiv) y, z, x; (xxv) −x, −z, y; (xxvi) x, z, −y; (xxvii) −z, −x, −y.

(II) ammonium oxopentafluorotitanate

Crystal data

(NH4)3TiOF5	Dx = 1.869 Mg m^−3
Mr = 213.03	Mo Kα radiation, λ = 0.71073 Å
Cubic, Fm3m	Cell parameters from 846 reflections
Hall symbol: -F 4 2 3	θ = 3.9–35.0°
a = 9.1144 (6) Å	µ = 1.17 mm^−1
V = 757.15 (9) Å^3	T = 297 K
Z = 4	Plate, colorless
F(000) = 432	0.32 × 0.26 × 0.20 mm

Data collection

Bruker P4 diffractometer	149 independent reflections
Radiation source: fine-focus sealed tube	149 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.020
Detector resolution: 8.33 pixels mm^-1	θmax = 39.0°, θmin = 3.9°
ω scans	h = −16→16
Absorption correction: multi-scan SADABS v.2.03; Bruker 1999	k = −16→11
Tmin = 0.706, Tmax = 0.800	l = −16→16
4778 measured reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.021	H-atom parameters not refined
wR(F^2) = 0.063	w = 1/[σ^2(Fo^2) + (0.0274P)^2 + 0.372P] where P = (Fo^2 + 2Fc^2)/3
S = 1.16	(Δ/σ)max = 0.025
149 reflections	Δρmax = 0.17 e Å^−3
18 parameters	Δρmin = −0.25 e Å^−3
0 restraints	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0176 (15)

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

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

	x	y	z	Uiso*/Ueq	Occ. (<1)
Ti1	0.01769 (12)	0.0000	0.0000	0.0272 (2)	0.17
N1	0.2597 (3)	0.2597 (3)	0.2597 (3)	0.0439 (6)	0.25
N2	0.5000	0.5000	0.5000	0.0665 (10)
O1	0.0000	0.0000	0.2036 (3)	0.0916 (16)	0.17
F1	0.0000	0.0000	0.2036 (3)	0.0916 (16)	0.17
F2	0.0000	0.0616 (4)	0.1980 (3)	0.0833 (11)	0.17
H11	0.2047	0.2047	0.2047	0.086*	0.25
H12	0.3147	0.3147	0.2047	0.086*	0.08
H13	0.3147	0.2047	0.3147	0.086*	0.08
H14	0.2047	0.3147	0.3147	0.086*	0.08
H2	0.5960	0.5192	0.5192	0.065*	0.13
H3	0.4430	0.4430	0.4430	0.065*	0.12

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ti1	0.0266 (6)	0.0276 (2)	0.0276 (2)	0.000	0.000	0.000
N1	0.0439 (6)	0.0439 (6)	0.0439 (6)	0.0056 (11)	0.0056 (11)	0.0056 (11)
N2	0.0665 (10)	0.0665 (10)	0.0665 (10)	0.000	0.000	0.000
O1	0.130 (2)	0.130 (2)	0.0144 (9)	0.000	0.000	0.000
F1	0.130 (2)	0.130 (2)	0.0144 (9)	0.000	0.000	0.000
F2	0.084 (2)	0.123 (3)	0.0429 (11)	0.000	0.000	−0.0390 (12)

Geometric parameters (Å, º)

Ti1—Ti1^i	0.2280 (15)	N1—F2^xiii	2.786 (4)
Ti1—Ti1^ii	0.322 (2)	N1—F2^xiv	2.864 (2)
Ti1—O1^iii	1.695 (3)	N1—F2^xv	2.8990 (19)
Ti1—F2^iv	1.897 (3)	N1—F2	3.030 (5)
Ti1—F2^iii	1.897 (3)	N1—F1^xvi	3.139 (4)
Ti1—F2^v	1.897 (3)	N1—F1^xvii	3.2421 (4)
Ti1—F2^vi	1.897 (3)	N1—F1^xviii	3.2421 (4)
Ti1—F1^i	2.017 (3)	N1—F1^xix	3.387 (5)
F2—F1^vii	2.649 (2)	N2—F1^xx	2.701 (3)
F2—F1^iii	2.649 (2)	N2—F1^xxi	2.701 (3)
F2—F2^viii	2.673 (4)	N2—F2^xiii	2.809 (3)
F2—F2^ix	2.673 (4)	N2—F2^xxii	2.809 (3)
N1—N1^x	0.251 (8)	N2—F2^xxiii	2.809 (3)
N1—N1^xi	0.251 (8)	N2—F2^xii	2.809 (3)
N1—N1^xii	0.251 (8)
Ti1^i—Ti1—Ti1^vii	60.0	N1^x—N1—N1^xi	60.014 (11)
Ti1^i—Ti1—Ti1^xix	90.0	N1^xii—N1—N1^xi	59.972 (10)
Ti1^vii—Ti1—Ti1^xix	60.0	F1^iii—Ti1—F2^iv	94.9 (1)
Ti1^i—Ti1—Ti1^iii	60.0	F1^iii—Ti1—F2^v	85.1 (1)
Ti1^vii—Ti1—Ti1^iii	90.0	F2^iv—Ti1—F2^v	89.6 (1)
Ti1^xix—Ti1—Ti1^iii	60.0	F1^iii—Ti1—F1^xxiv	180.0
N1^x—N1—N1^xii	60.014 (12)	F2^iv—Ti1—F2^iii	170.3 (2)

Symmetry codes: (i) −y, −z, −x; (ii) −x, −y, −z; (iii) z, x, y; (iv) z, y, −x; (v) z, −y, x; (vi) z, −x, −y; (vii) −z, −x, −y; (viii) −x, −z, y; (ix) x, z, −y; (x) x, −y+1/2, −z+1/2; (xi) −x+1/2, y, −z+1/2; (xii) −x+1/2, −y+1/2, z; (xiii) z, −y+1/2, x+1/2; (xiv) −z+1/2, y, −x+1/2; (xv) −z+1/2, −y+1/2, x; (xvi) y+1/2, z, x+1/2; (xvii) −z+1/2, −x+1/2, −y; (xviii) −x, −y+1/2, −z+1/2; (xix) y, z, x; (xx) −y+1/2, −z+1, −x+1/2; (xxi) x+1/2, y+1/2, z; (xxii) x+1/2, z, −y+1/2; (xxiii) −y+1/2, −x+1/2, z; (xxiv) −y, x, z.

(III) rubidium potassium oxopentafuorotitanate

Crystal data

Rb2KTiOF5	Dx = 3.476 Mg m^−3
Mr = 368.94	Mo Kα radiation, λ = 0.71073 Å
Cubic, Fm3m	Cell parameters from 512 reflections
Hall symbol: -F 4 2 3	θ = 4.0–40.5°
a = 8.9002 (1) Å	µ = 15.55 mm^−1
V = 705.02 (1) Å^3	T = 297 K
Z = 4	Formless, colorless
F(000) = 672	0.28 × 0.25 × 0.20 mm

Data collection

Bruker P4 diffractometer	198 independent reflections
Radiation source: fine-focus sealed tube	138 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.029
Detector resolution: 8.33 pixels mm^-1	θmax = 46.0°, θmin = 4.0°
ω scans	h = −17→18
Absorption correction: multi-scan SADABS v.2.03; Bruker 1999	k = −17→18
Tmin = 0.098, Tmax = 0.147	l = −17→18
5318 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.021	w = 1/[σ^2(Fo^2) + (0.0304P)^2 + 2.5031P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.073	(Δ/σ)max = 0.032
S = 1.19	Δρmax = 0.75 e Å^−3
138 reflections	Δρmin = −1.07 e Å^−3
16 parameters	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.00044 (9)

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

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

	x	y	z	Uiso*/Ueq	Occ. (<1)
Ti1	0.0000	0.0000	0.0000	0.01638 (6)
Rb1	0.25798 (2)	0.25798 (2)	0.25798 (2)	0.02154 (4)	0.25
K1	0.5000	0.5000	0.5000	0.01367 (6)
O1	0.0000	0.0000	0.21506 (12)	0.0354 (3)	0.08
F1	0.0000	0.0000	0.21506 (12)	0.0354 (3)	0.58
O2	0.0000	0.0328 (5)	0.2077 (3)	0.0446 (16)	0.02
F2	0.0000	0.0328 (5)	0.2077 (3)	0.0446 (16)	0.06

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ti1	0.01638 (6)	0.01638 (6)	0.01638 (6)	0.000	0.000	0.000
Rb1	0.02154 (4)	0.02154 (4)	0.02154 (4)	0.00104 (7)	0.00104 (7)	0.00104 (7)
K1	0.01367 (6)	0.01367 (6)	0.01367 (6)	0.000	0.000	0.000
O1	0.0487 (4)	0.0487 (4)	0.0087 (3)	0.000	0.000	0.000
F1	0.0487 (4)	0.0487 (4)	0.0087 (3)	0.000	0.000	0.000
O2	0.040 (2)	0.083 (5)	0.0106 (8)	0.000	0.000	−0.0132 (15)
F2	0.040 (2)	0.083 (5)	0.0106 (8)	0.000	0.000	−0.0132 (15)

Geometric parameters (Å, º)

Ti1—F1^i	1.914 (2)	Rb1—F2^i	2.958 (3)
Ti1—F1^ii	1.914 (2)	Rb1—F2^xi	2.972 (3)
Ti1—F2^iii	1.872 (3)	Rb1—F2^xii	3.080 (3)
Ti1—O2^iv	1.872 (3)	K1—F1^xiii	2.5360 (11)
Ti1—F2^v	1.872 (3)	K1—F1^xiv	2.5360 (11)
Ti1—F2^vi	1.872 (3)	K1—F2^xv	2.618 (3)
Rb1—Rb1^vii	0.2009 (6)	K1—F2^xvi	2.618 (3)
Rb1—Rb1^viii	0.2009 (6)	K1—F2^xvii	2.618 (3)
Rb1—Rb1^ix	0.2009 (6)	K1—F2^i	2.618 (3)
Rb1—F1^ii	3.070 (3)	F1—F2^xviii	2.677 (5)
Rb1—F1^x	3.157 (3)	F2—F2^xix	2.647 (5)
Rb1—F2^ii	2.882 (3)
F2^iv—Ti1—F2^xx	180.0 (3)	F1^iv—Ti1—F2^xx	90.0 (3)
F2^xxi—Ti1—F2^xxii	180.0 (3)	F2^iv—Ti1—F2^xxi	90.0 (4)

Symmetry codes: (i) x+1/2, z, −y+1/2; (ii) z, −x+1/2, −y+1/2; (iii) −x, −y, −z; (iv) −z, −y, x; (v) −y, −z, −x; (vi) y, z, x; (vii) x, −y+1/2, −z+1/2; (viii) −x+1/2, y, −z+1/2; (ix) −x+1/2, −y+1/2, z; (x) −z, −x+1/2, −y+1/2; (xi) −y+1/2, −x+1/2, z; (xii) −y+1/2, z, −x+1/2; (xiii) −y+1/2, −z+1, −x+1/2; (xiv) −z+1, −x+1/2, −y+1/2; (xv) −z+1, y+1/2, −x+1/2; (xvi) z, −y+1/2, x+1/2; (xvii) −x+1/2, −z+1, y+1/2; (xviii) −z, x, y; (xix) −y, z, −x; (xx) z, y, −x; (xxi) x, −z, −y; (xxii) −x, z, y.

(IV) rubidium potassium oxopentafuorotitanate

Crystal data

Rb2KTiOF5	Dx = 3.490 Mg m^−3
Mr = 368.94	Mo Kα radiation, λ = 0.71073 Å
Cubic, Fm3m	Cell parameters from 512 reflections
Hall symbol: -F 4 2 3	θ = 4.0–39.8°
a = 8.8879 (2) Å	µ = 15.61 mm^−1
V = 702.10 (3) Å^3	T = 218 K
Z = 4	Formless, colorless
F(000) = 672	0.35 × 0.25 × 0.25 mm

Data collection

Bruker P4 diffractometer	155 independent reflections
Radiation source: fine-focus sealed tube	130 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.030
Detector resolution: 8.33 pixels mm^-1	θmax = 40.9°, θmin = 4.0°
ω scans	h = −16→14
Absorption correction: multi-scan SADABS v.2.03; Bruker 1999	k = −16→14
Tmin = 0.074, Tmax = 0.112	l = −16→16
4779 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.023	w = 1/[σ^2(Fo^2) + (0.0157P)^2 + 5.640P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.061	(Δ/σ)max = 0.046
S = 1.33	Δρmax = 1.09 e Å^−3
130 reflections	Δρmin = −0.84 e Å^−3
12 parameters	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.00086 (17)

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

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

	x	y	z	Uiso*/Ueq	Occ. (<1)
Ti1	0.0185 (2)	0.0000	0.0000	0.0027 (4)	0.17
Rb1	0.25798 (8)	0.25798 (8)	0.25798 (8)	0.01411 (13)	0.25
K1	0.5000	0.5000	0.5000	0.01017 (19)
O1	0.0000	0.0000	0.2147 (2)	0.0358 (6)	0.17
F1	0.0000	0.0000	0.2147 (2)	0.0358 (6)	0.83

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ti1	0.0050 (11)	0.0015 (3)	0.0015 (3)	0.000	0.000	0.000
Rb1	0.01411 (13)	0.01411 (13)	0.01411 (13)	0.0007 (2)	0.0007 (2)	0.0007 (2)
K1	0.01017 (19)	0.01017 (19)	0.01017 (19)	0.000	0.000	0.000
O1	0.0506 (8)	0.0506 (8)	0.0064 (7)	0.000	0.000	0.000
F1	0.0506 (8)	0.0506 (8)	0.0064 (7)	0.000	0.000	0.000

Geometric parameters (Å, º)

Ti1—Ti1^i	0.232 (3)	Rb1—Rb1^x	0.201 (2)
Ti1—Ti1^ii	0.232 (3)	Rb1—Rb1^xi	0.201 (2)
Ti1—Ti1^iii	0.232 (3)	Rb1—F1^xviii	3.0663 (10)
Ti1—Ti1^iv	0.232 (3)	Rb1—F1^xix	3.0663 (10)
Ti1—Ti1^v	0.328 (4)	Rb1—F1^xx	3.0663 (10)
Ti1—F1^iv	1.744 (3)	Rb1—O1^xviii	3.0663 (10)
Ti1—F1^i	1.915 (2)	Rb1—O1^xix	3.0663 (10)
Ti1—F1^v	1.915 (2)	Rb1—O1^xx	3.0663 (10)
Ti1—F1	1.915 (2)	Rb1—F1^xxi	3.1534 (2)
Ti1—F1^iii	1.915 (2)	Rb1—F1^xxii	3.1533 (2)
Ti1—F1^ii	2.072 (3)	Rb1—F1^xxiii	3.1533 (2)
Ti1—Rb1^vi	3.7128 (11)	Rb1—F1^iii	3.2654 (12)
Ti1—Rb1^vii	3.7128 (11)	Rb1—F1^iv	3.2654 (12)
Ti1—Rb1^viii	3.7128 (11)	Rb1—O1^iii	3.2654 (12)
Ti1—Rb1^ix	3.7128 (11)	K1—F1^xviii	2.536 (2)
Ti1—Rb1^x	3.7191 (10)	K1—F1^xix	2.536 (2)
Ti1—Rb1^xi	3.7191 (10)	K1—F1^xx	2.536 (2)
Ti1—Rb1^xii	3.7191 (10)	K1—O1^xviii	2.536 (2)
Ti1—Rb1^xiii	3.7191 (10)	K1—O1^xix	2.536 (2)
Ti1—Rb1^xiv	3.7191 (10)	K1—O1^xx	2.536 (2)
Ti1—Rb1^xv	3.7191 (10)	F1—F1^i	2.698 (3)
Ti1—Rb1^xvi	3.7191 (10)	F1—F1^ii	2.698 (3)
Ti1—Rb1^xvii	3.7191 (10)	F1—F1^iii	2.698 (3)
Ti1—Rb1	3.8789 (16)	F1—F1^iv	2.698 (3)
Rb1—Rb1^vi	0.201 (2)
Ti1^i—Ti1—Ti1^ii	60.0	F1^i—Ti1—O1^v	89.579 (9)
Ti1^i—Ti1—Ti1^iii	90.0	F1^v—Ti1—O1^i	89.579 (9)
Ti1^ii—Ti1—Ti1^iii	60.0	O1^i—Ti1—O1^v	89.579 (9)
Ti1^i—Ti1—Ti1^iv	60.0	F1^i—Ti1—F1^ii	85.08 (5)
Ti1^ii—Ti1—Ti1^iv	90.0	F1^v—Ti1—F1^ii	85.08 (5)
Ti1^iii—Ti1—Ti1^iv	60.0	F1^iii—Ti1—F1^ii	85.08 (5)
F1^iv—Ti1—F1^i	94.92 (5)	F1^iii—Ti1—F1^ii	85.08 (5)
O1^iv—Ti1—F1^i	94.92 (5)	F1^i—Ti1—F1^iii	170.16 (11)
F1^iv—Ti1—F1^v	94.92 (5)	F1^iv—Ti1—O1^ii	180.0
O1^iv—Ti1—F1^v	94.92 (5)	O1^iv—Ti1—O1^ii	180.0
F1^i—Ti1—F1^v	89.579 (9)

Symmetry codes: (i) −y, −z, −x; (ii) −z, −x, −y; (iii) y, z, x; (iv) z, x, y; (v) −x, −y, −z; (vi) x, −y+1/2, −z+1/2; (vii) x, −y+1/2, z−1/2; (viii) x, y−1/2, −z+1/2; (ix) x, y−1/2, z−1/2; (x) −x+1/2, y, −z+1/2; (xi) −x+1/2, −y+1/2, z; (xii) −x+1/2, y−1/2, −z; (xiii) −x+1/2, −y, z−1/2; (xiv) −x+1/2, y−1/2, z; (xv) −x+1/2, y, z−1/2; (xvi) −x+1/2, −y+1/2, −z; (xvii) −x+1/2, −y, −z+1/2; (xviii) y+1/2, z, x+1/2; (xix) z, x+1/2, y+1/2; (xx) x+1/2, y+1/2, z; (xxi) −y+1/2, −z+1/2, −x; (xxii) −y, −z+1/2, −x+1/2; (xxiii) −z+1/2, −x+1/2, −y.