Disordering of the [NbOF₅]^2- complex anions in bis­(glycinium) penta­fluoridooxidoniobate(V) and bis­([beta]-alaninium) penta­fluorido­oxido­niobate(V) dihydrate

The title compounds, (C₂H₆NO₂)₂[NbOF₅], (I), and (C₃H₈NO₂)₂[NbOF₅]·2H₂O, (II), are built from isolated distorted octa­hedral [NbOF₅]^2- complex anions, amino acid cations and water mol­ecules [for (II)]. In the penta­fluorido­oxido­nio­bate(V) anions, the Nb and O atoms, and the F atoms in trans positions with respect to the O atoms, are disordered about an inversion centre for both structures. The Nb atoms are shifted from the inversion centres by distances of 0.1455 (1) and 0.1263 (2) Å for (I) and (II), respectively. The Nb=O and Nb-F(trans) bond lengths are 1.7952 (3) and 2.0862 (3) Å, respectively, for (I), and 1.8037 (7) and 2.0556 (7) Å for (II). In the crystal structures, cations and water mol­ecules [for (II)] are linked to the [NbOF₅]^2- anions via hydrogen bonds. This study demonstrates the possibility of true geometry determination of disordered [NbOF₅]^2- complex anions in centrosymmetric structures.

S1. Comment

Recently, hybrid organic–inorganic compounds have been synthesized and intensively studied due to their exceptional importance for designing materials with structure-dependent properties, such as nonlinear optical activity, superionic conductivity, and piezoelectric and ferroelectric properties. Special attention has been given to the compounds of the early transition metals with distorted coordination polyhedra, in which the metal atoms are displaced from the centre of the polyhedron toward a vertex, edge or face. These metals include niobium, characterized by the displacement of the Nb atom from the centre of the octahedron in the [NbOF₅]^2- anion in the direction of the O atom along the Nb═O bond, caused by electronic effects [`primary' distortion (Welk et al., 2002; Izumi et al., 2005)]. Sometimes in the [NbOF₅]^2- anion, the Nb atom is located on or near any element of symmetry that results in a statistical arrangement of ligands around it and this complicates analysis of the accurate geometry of the complex anions. The present work deals with the determination of the crystal structures of bis(glycinium) pentafluoridooxidoniobate(V), (I), and bis(β-alaninium) pentafluoridooxidoniobate(V) dihydrate, (II), and the study of the disordering of the [NbOF₅]^2- complex anions in these compounds.

For both structures, the locations of the Nb atoms at the inversion centres were determined by direct methods and confirmed by the Patterson function. Thus, initially the structures of (I) and (II) were solved with the Nb atoms located at centres of symmetry [Wyckoff positions 2a for (I) and 1a for (II)] and atoms F1 and O1 occupied the same position. Refinement by least-squares method with anisotropic displacement parameters for all non-H atoms resulted in R [F² > 2σ(F²)] values of 0.0579 for (I) and 0.0255 for (II). At this stage, the lengths of the Nb1—F1/O1 bonds were approximately equal to the average mean values of Nb═O and Nb—F(trans) bonds for ordered structures (Pushilin et al., 2007; Zhu et al., 2005; Zhu & Tang, 2005, 2006; Sarin et al., 1977), namely 1.939 Å for (I) and 1.930 Å for (II). Analysis of the anisotropic displacement parameters showed that the Nb1 atoms had significant thermal displacement along the Nb1—F1/O1 directions in both structures (Fig. 1a and c). The maximal axis of the Nb1 displacement ellipsoid (σ₁) had angles with the Nb1—F1/O1 bond of 8° for (I) and 1° for (II), which make no physical sense, since the Nb═O bond is strongest in [NbOF₅]^2- anions (Kharitonov & Buslaev, 1964; Welk et al., 2002; Izumi et al., 2005). In addition, for difference electron-density syntheses with isotropic displacement parameters for the Nb1 atoms, the highest peaks (Q1) [28 e Å^-3 for (I) and 10 e Å^-3 for (II)] were located along the Nb1—F1/O1 bonds at distances from the Nb atoms of 0.33 and 0.47 Å for (I) and (II), respectively. In our opinion, the above factors indicate displacement of the Nb1 atoms from the centres of symmetry towards the O atoms along the Nb1—F1/O1 directions. We have checked this assumption by placing Nb1 atoms approximately in the middle of the Nb1···Q1 distances with half-occupancy of the Nb1 sites. Refinement led to determination of the Nb1 positions at distances of 0.146 Å for (I) and 0.128 Å for (II) from the centres of symmetry and demonstrated satisfactory anisotropy of the Nb1 atoms (Fig. 1b and d) [angles between σ₁ and the Nb1—F1/O1 direction are 54° for (I) and 37° for (II)]. The resulting geometric parameters of the [NbOF₅]^2- anion are comparable with those of the same anions for ordered structures. For similar reasons, the Nb atom was moved from the twofold rotation axis in the Na₂[NbOF₅] structure (Stomberg, 1984), which also resulted in a more accurate geometry for the [NbOF₅]^2- anion.

Due to the statistical distribution of the Nb atoms in (I) and (II), one should expect splitting of the ligand positions as well. Refinement of models where ligand positions were split into two sites was performed for both structures. However, in our experiments these positions were indistinguishable within the limits of experimental error. Thus, in (I) and (II) the complex anions are statistically disordered about an inversion centre. The Nb atoms are coordinated by five F atoms and one O atom, forming distorted octahedra. The Nb—F bond in a trans position to the Nb═O bond is significantly longer than theother four Nb—F bonds in the polyhedra (Tables 1 and 3). The Nb1 atoms are displaced from the equatorial planes of the octahedra in the direction of the axial atoms O1 by 0.1455 (1) and 0.1263 (2) Å for (I) and (II), respectively.

The asymmetric unit of (I) contains one-half of an [NbOF₅]^2- anion and one glycinium cation (C₂H₆NO₂⁺). The glycinium cation is protonated on the amine group and thus carries a positive charge. The C1—O3 bonds [1.3169 (4) Å] are much longer than C1—O2 [1.2158 (4) Å], indicating localized single and double bonds, respectively. The glycinium cations are linked by intermolecular N—H···O hydrogen bonds to form layers parallel to the ac plane (Fig. 2). By a combination of N—H···F, N—H···O and O—H···F hydrogen bonds (Table 2 and Fig. 3), some of which are weak and bifurcated or trifurcated, the layers are linked to the [NbOF₅]^2- anions. It should be noted that the structure includes two short O—H···F/O hydrogen bonds between the hydroxyl groups of the glycinium cations and the axial atoms F1 and O1 having the highest negative charge in the [NbOF₅]^2- anion (Izumi et al., 2005). Also, in the structure of (I) there is a very weak non-covalent interaction, F3(δ-)···C1ⁱⁱⁱ(δ+) [2.8446 (5) Å; symmetry code: (iii) ? Please complete], which is slightly less than the sum of the van der Waals radii of F and C atoms (3.17 Å; Bondi, 1964). Similar short contacts between the F atom and the C atom of a carboxyl group are also present in the structures of bis(DL-valinium) pentafluoridooxidoniobate(V) (2.840 Å; Pushilin et al., 2007), sodium tris(glycinium) bis(hexafluorosilicate) glycine trisolvate (2.870 Å; Narayana et al., 2007) and 4-methylbenzoic acidium hexafluoro-arsenate p-toluic acid (2.920 and 2.940 Å; Lindeman et al., 2005).

The asymmetric unit of (II) contains one-half of an [NbOF₅]^2- anion, one β-alaninium cation (C₃H₈NO₂⁺) and one water molecule. The positive charge of the cation is localized on the amine group. The single (C1—O3) and double (C1═O2) bonds in the carboxyl group are 1.3270 (11) and 1.2097 (10) Å, respectively. The cations and water molecules are linked by N—H···O hydrogen bonds to form chains along the b axis and these chains are packed into layers parallel to the ab plane (Fig. 4 and Table 4). The anions, cations and water molecules are linked by a network of O—H···F and N—H···F hydrogen bonds into a three-dimensional framework (Fig. 5). As in (I), the shortest hydrogen bonds are formed with atoms F1 and O1 of the [NbOF₅]^2- anion.

Related literature

For related literature, see: Bondi (1964); Izumi et al. (2005); Kharitonov & Buslaev (1964); Lindeman et al. (2005); Narayana et al. (2007); Pushilin et al. (2007); Sarin et al. (1977); Stomberg (1984); Welk et al. (2002); Zhu & Tang (2005, 2006); Zhu, Liu, Wang & Tang (2005).

S2. Experimental

Compound (I) was synthesized by the reaction of Nb₂O₅ (1.33 g, 5 mmol) with glycine (1.50 g, 20 mmol) in a solution of hydrofluoric acid (48%, 40 ml). The solution was allowed to evaporate slowly at room temperature. After a few days, colourless crystals suitable for X-ray diffraction were obtained. These were separated from the solution, washed with a small amount of acetone and dried to constant weight in air.

Compound (II) was synthesized using a route similar to that for (I), by the reaction of Nb₂O₅ (1.33 g, 5 mmol) with β-alanine (1.78 g, 20 mmol) in a solution of hydrofluoric acid (48%, 40 ml).

S3. Refinement

The Nb1 atoms were refined with site occupancy 0.5. Atoms F1 and O1 were refined together, assuming that their positional and displacement parameters are the same, with site occupancies of 0.5. For the glycinium and β-alaninium cations, after checking their presence in difference maps, all H atoms were placed in geometrically idealized positions and refined in the riding-model approximation, with C—H = 0.99 or 0.98 Å, N—H = 0.91 or 0.90 Å and O—H = 0.84 or 0.83 Å, and with U_iso(H) = 1.2 or 1.5U_eq(C,N,O). For water molecules, the H atoms were located in a difference map and refined with U_iso(H) = 1.5U_eq(O).

Computing details

For both compounds, data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 2003); data reduction: SAINT (Bruker, 2003); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: XP in SHELXTL (Sheldrick, 2008); software used to prepare material for publication: publCIF (Westrip, 2008).

Figures

	Fig. 1. The [NbOF5]^2- anions, showing the displacement of the Nb1 atoms from the inversion centre [(a) for (I) and (c) for (II)], and the disordered displacement of the Nb1 atoms [(b) for (I) and (d) for (II)]. Ellipsoids are drawn at the 50% probability level. [Symmetry code: (i) ? Please complete]
	Fig. 2. A fragment of the cationic layer of (I), viewed parallel to the ac plane. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii. Hydrogen bonds are shown as dotted lines. [Symmetry codes: (iii) ?; (vi) ? Please complete]
	Fig. 3. The structure of (I), viewed along the a axis.
	Fig. 4. A fragment of the chain of hydrogen-bonded cations and water molecules of (II). Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii. Hydrogen bonds are shown as dotted lines. [Symmetry codes: (iii) ?; (v) ? Please complete]
	Fig. 5. The structure of (II), viewed along the c axis.

(I) bis(glycinium) pentafluoridooxidoniobate(V)

Crystal data

(C2H6NO2)2[NbOF5]	F(000) = 352
Mr = 356.07	Dx = 2.263 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 1882 reflections
a = 5.3532 (1) Å	θ = 3.8–50.5°
b = 10.8585 (3) Å	µ = 1.24 mm^−1
c = 8.9913 (2) Å	T = 173 K
β = 90.022 (1)°	Spherical, colourless
V = 522.64 (2) Å^3	0.28 × 0.14 (radius) mm
Z = 2

Data collection

Bruker SMART 1000 CCD area-detector diffractometer	5525 independent reflections
Radiation source: fine-focus sealed tube	5027 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.033
Detector resolution: 8.33 pixels mm^-1	θmax = 50.5°, θmin = 2.9°
ω scans	h = −11→11
Absorption correction: for a sphere (SADABS; Bruker, 2003)	k = −23→21
Tmin = 0.669, Tmax = 0.723	l = −19→19
19292 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)] = 0.028	H-atom parameters constrained
wR(F^2) = 0.075	w = 1/[σ^2(Fo^2) + (0.035P)^2 + 0.0886P] where P = (Fo^2 + 2Fc^2)/3
S = 1.11	(Δ/σ)max = 0.011
5525 reflections	Δρmax = 1.00 e Å^−3
85 parameters	Δρmin = −0.95 e Å^−3
0 restraints	Extinction correction: SHELXTL (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0379 (13)

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)
Nb1	0.009533 (12)	0.507853 (5)	0.511909 (6)	0.00829 (1)	0.50
F1	0.11202 (5)	0.59455 (3)	0.67061 (3)	0.01574 (4)	0.50
O1	0.11202 (5)	0.59455 (3)	0.67061 (3)	0.01574 (4)	0.50
F2	0.17782 (6)	0.61073 (3)	0.36979 (3)	0.02106 (5)
F3	0.28697 (5)	0.39493 (3)	0.51657 (3)	0.01911 (5)
O2	0.60417 (6)	0.62252 (3)	−0.12855 (3)	0.01781 (5)
O3	1.00718 (5)	0.62993 (3)	−0.05875 (3)	0.01441 (4)
H3	1.0333	0.6216	−0.1503	0.022*
N1	0.44755 (6)	0.70615 (3)	0.13990 (3)	0.01485 (5)
H1A	0.4570	0.7898	0.1363	0.022*
H1B	0.3776	0.6827	0.2276	0.022*
H1C	0.3519	0.6785	0.0632	0.022*
C1	0.76489 (6)	0.63467 (3)	−0.03415 (3)	0.01119 (4)
C2	0.70120 (6)	0.65334 (3)	0.12786 (3)	0.01340 (5)
H2A	0.7082	0.5735	0.1809	0.016*
H2B	0.8240	0.7097	0.1742	0.016*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Nb1	0.00946 (2)	0.00882 (2)	0.00660 (2)	0.00033 (1)	0.00060 (1)	−0.00023 (1)
F1	0.01719 (8)	0.01886 (8)	0.01118 (7)	−0.00143 (7)	0.00056 (6)	−0.00375 (6)
O1	0.01719 (8)	0.01886 (8)	0.01118 (7)	−0.00143 (7)	0.00056 (6)	−0.00375 (6)
F2	0.02009 (9)	0.02075 (9)	0.02233 (9)	−0.00249 (8)	0.00680 (8)	0.00799 (8)
F3	0.01452 (8)	0.01736 (8)	0.02543 (10)	0.00518 (7)	0.00000 (8)	−0.00019 (8)
O2	0.01470 (8)	0.02780 (12)	0.01092 (7)	−0.00077 (9)	−0.00224 (7)	−0.00257 (8)
O3	0.01184 (7)	0.02010 (9)	0.01129 (7)	0.00072 (7)	0.00138 (6)	−0.00087 (7)
N1	0.01280 (8)	0.01951 (10)	0.01223 (8)	−0.00037 (8)	0.00254 (7)	−0.00162 (8)
C1	0.01213 (8)	0.01251 (8)	0.00894 (7)	−0.00012 (7)	0.00041 (7)	−0.00016 (7)
C2	0.01432 (10)	0.01723 (10)	0.00865 (8)	0.00147 (8)	0.00038 (7)	0.00044 (7)

Geometric parameters (Å, º)

Nb1—Nb1^i	0.2921 (1)	F3—Nb1^i	1.9233 (3)
Nb1—O1	1.7952 (3)	O2—C1	1.2155 (4)
Nb1—F1^i	2.0862 (3)	O3—C1	1.3169 (4)
Nb1—F2	1.9218 (3)	O3—H3	0.8400
Nb1—F2^i	1.9484 (3)	N1—C2	1.4780 (5)
Nb1—F3^i	1.9233 (3)	N1—H1A	0.9100
Nb1—F3	1.9264 (3)	N1—H1B	0.9100
Nb1—F1	1.7952 (3)	N1—H1C	0.9100
Nb1—O1^i	2.0862 (3)	C1—C2	1.5099 (4)
F1—Nb1^i	2.0862 (3)	C2—H2A	0.9900
F2—Nb1^i	1.9484 (3)	C2—H2B	0.9900
F1—Nb1—F2	94.616 (13)	F3—Nb1—O1^i	85.301 (12)
F1—Nb1—F3^i	94.011 (13)	F2^i—Nb1—O1^i	85.223 (12)
F2—Nb1—F3^i	88.823 (13)	C1—O3—H3	109.5
F1—Nb1—F3	94.653 (13)	C2—N1—H1A	109.5
F2—Nb1—F3	91.312 (13)	C2—N1—H1B	109.5
F3^i—Nb1—F3	171.296 (3)	H1A—N1—H1B	109.5
F1—Nb1—F2^i	94.006 (13)	C2—N1—H1C	109.5
F2—Nb1—F2^i	171.377 (3)	H1A—N1—H1C	109.5
F3^i—Nb1—F2^i	90.600 (13)	H1B—N1—H1C	109.5
F3—Nb1—F2^i	87.963 (13)	O2—C1—O3	125.13 (3)
F1—Nb1—F1^i	179.228 (4)	O2—C1—C2	121.89 (3)
F2—Nb1—F1^i	86.155 (12)	O3—C1—C2	112.96 (3)
F3^i—Nb1—F1^i	86.025 (12)	N1—C2—C1	109.30 (3)
F3—Nb1—F1^i	85.301 (12)	N1—C2—H2A	109.8
F2^i—Nb1—F1^i	85.223 (12)	C1—C2—H2A	109.8
F1—Nb1—O1^i	179.228 (4)	N1—C2—H2B	109.8
F2—Nb1—O1^i	86.155 (12)	C1—C2—H2B	109.8
F3^i—Nb1—O1^i	86.025 (12)	H2A—C2—H2B	108.3
O2—C1—C2—N1	−24.12 (5)	O3—C1—C2—N1	157.61 (3)

Symmetry code: (i) −x, −y+1, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3···(F1/O1)^ii	0.84	1.69	2.5268 (4)	174
N1—H1A···O2^iii	0.91	2.45	2.9149 (5)	112
N1—H1A···(F1/O1)^iv	0.91	2.25	2.8259 (4)	120
N1—H1A···F3^v	0.91	2.25	2.8640 (4)	124
N1—H1B···F2	0.91	1.84	2.7264 (4)	164
N1—H1C···O3^vi	0.91	2.21	3.0707 (4)	158
N1—H1C···O2	0.91	2.27	2.7121 (4)	109
C2—H2A···(F1/O1)^vii	0.99	2.46	3.3952 (4)	158

Symmetry codes: (ii) x+1, y, z−1; (iii) x, −y+3/2, z+1/2; (iv) x, −y+3/2, z−1/2; (v) −x+1, y+1/2, −z+1/2; (vi) x−1, y, z; (vii) −x+1, −y+1, −z+1.

(II) bis(β-alaninium) pentafluoridooxidoniobate(V) dihydrate

Crystal data

(C3H8NO2)2[NbOF5]·2H2O	Z = 1
Mr = 420.15	F(000) = 212
Triclinic, P1	Dx = 1.872 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 6.9552 (8) Å	Cell parameters from 3133 reflections
b = 7.2092 (8) Å	θ = 31.0–3.7°
c = 8.0205 (9) Å	µ = 0.90 mm^−1
α = 74.609 (2)°	T = 203 K
β = 86.223 (2)°	Prism, colourless
γ = 74.016 (2)°	0.27 × 0.25 × 0.24 mm
V = 372.74 (7) Å^3

Data collection

Bruker SMART 1000 CCD area-detector diffractometer	2215 independent reflections
Radiation source: fine-focus sealed tube	2114 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.021
Detector resolution: 8.33 pixels mm^-1	θmax = 31.4°, θmin = 3.7°
ω scans	h = −9→9
Absorption correction: multi-scan (SADABS; Bruker, 2003)	k = −10→10
Tmin = 0.794, Tmax = 0.814	l = −11→11
4033 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)] = 0.025	Hydrogen site location: difference Fourier map
wR(F^2) = 0.064	H atoms treated by a mixture of independent and constrained refinement
S = 1.15	w = 1/[σ^2(Fo^2) + (0.0266P)^2 + 0.1346P] where P = (Fo^2 + 2Fc^2)/3
2215 reflections	(Δ/σ)max = 0.008
108 parameters	Δρmax = 0.53 e Å^−3
0 restraints	Δρmin = −0.56 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)
Nb1	0.99134 (4)	0.00837 (4)	0.98533 (3)	0.01554 (3)	0.50
F1	0.86210 (9)	0.08616 (10)	0.78035 (8)	0.02602 (15)	0.50
O1	0.86210 (9)	0.08616 (10)	0.78035 (8)	0.02602 (15)	0.50
F2	0.82582 (9)	0.22574 (9)	1.06818 (8)	0.02974 (15)
F3	0.81570 (9)	−0.15627 (9)	1.09415 (8)	0.03148 (14)
O2	0.75089 (10)	0.90443 (10)	0.48842 (9)	0.02560 (17)
O3	1.06682 (10)	0.71644 (11)	0.53072 (9)	0.02688 (17)
H3	1.0836	0.7918	0.4361	0.040*
O4	0.52264 (10)	0.69774 (10)	0.29964 (10)	0.02650 (17)
H1	0.424 (2)	0.770 (2)	0.2623 (19)	0.040*
H2	0.611 (2)	0.749 (2)	0.2484 (19)	0.040*
N1	0.46814 (11)	0.69786 (11)	0.68341 (10)	0.02143 (17)
H1A	0.4902	0.7650	0.5753	0.032*
H1B	0.3448	0.7549	0.7168	0.032*
H1C	0.4779	0.5701	0.6856	0.032*
C1	0.87584 (13)	0.76627 (12)	0.57476 (11)	0.01814 (18)
C2	0.83121 (13)	0.63095 (13)	0.74223 (12)	0.02096 (19)
H2A	0.9257	0.6220	0.8313	0.025*
H2B	0.8509	0.4966	0.7267	0.025*
C3	0.61968 (14)	0.70374 (14)	0.80351 (12)	0.0227 (2)
H3A	0.6033	0.6200	0.9188	0.027*
H3B	0.5971	0.8410	0.8127	0.027*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Nb1	0.01307 (4)	0.01579 (4)	0.01655 (6)	−0.00491 (3)	0.00424 (4)	−0.00204 (4)
F1	0.0222 (3)	0.0363 (3)	0.0179 (3)	−0.0084 (2)	−0.0015 (2)	−0.0032 (2)
O1	0.0222 (3)	0.0363 (3)	0.0179 (3)	−0.0084 (2)	−0.0015 (2)	−0.0032 (2)
F2	0.0272 (3)	0.0278 (2)	0.0324 (3)	−0.0016 (2)	0.0070 (2)	−0.0124 (2)
F3	0.0304 (2)	0.0400 (3)	0.0302 (3)	−0.0232 (2)	0.0098 (2)	−0.0074 (2)
O2	0.0228 (3)	0.0231 (3)	0.0254 (3)	−0.0047 (2)	−0.0006 (3)	0.0017 (2)
O3	0.0185 (3)	0.0318 (3)	0.0252 (3)	−0.0065 (2)	0.0031 (3)	0.0003 (3)
O4	0.0195 (3)	0.0250 (3)	0.0335 (3)	−0.0086 (2)	0.0011 (3)	−0.0024 (3)
N1	0.0181 (3)	0.0215 (3)	0.0243 (3)	−0.0070 (2)	0.0022 (3)	−0.0039 (3)
C1	0.0189 (3)	0.0193 (3)	0.0181 (3)	−0.0080 (3)	−0.0002 (3)	−0.0050 (3)
C2	0.0199 (3)	0.0222 (3)	0.0191 (4)	−0.0079 (3)	−0.0019 (3)	0.0005 (3)
C3	0.0243 (4)	0.0274 (3)	0.0203 (4)	−0.0121 (3)	0.0042 (3)	−0.0082 (3)

Geometric parameters (Å, º)

Nb1—Nb1^i	0.2551 (5)	O3—H3	0.8300
Nb1—F1^i	2.0556 (7)	O4—H1	0.761 (14)
Nb1—O1	1.8037 (7)	O4—H2	0.836 (16)
Nb1—F2	1.9186 (7)	N1—C3	1.4902 (13)
Nb1—F2^i	1.9443 (7)	N1—H1A	0.9000
Nb1—F3	1.9420 (7)	N1—H1B	0.9000
Nb1—F3^i	1.9129 (7)	N1—H1C	0.9000
Nb1—O1^i	2.0556 (7)	C1—C2	1.5062 (12)
F1—Nb1^i	2.0556 (7)	C2—C3	1.5159 (13)
F2—Nb1^i	1.9443 (7)	C2—H2A	0.9800
F3—Nb1^i	1.9129 (7)	C2—H2B	0.9800
O2—C1	1.2097 (10)	C3—H3A	0.9800
O3—C1	1.3270 (11)	C3—H3B	0.9800
F1—Nb1—F3^i	94.73 (3)	C3—N1—H1A	109.5
F1—Nb1—F2	94.04 (3)	C3—N1—H1B	109.5
F3^i—Nb1—F2	90.42 (3)	H1A—N1—H1B	109.5
F1—Nb1—F3	92.76 (3)	C3—N1—H1C	109.5
F3^i—Nb1—F3	172.461 (14)	H1A—N1—H1C	109.5
F2—Nb1—F3	89.86 (3)	H1B—N1—H1C	109.5
F1—Nb1—F2^i	93.42 (3)	O2—C1—O3	123.46 (8)
F3^i—Nb1—F2^i	89.95 (3)	O2—C1—C2	123.74 (8)
F2—Nb1—F2^i	172.466 (14)	O3—C1—C2	112.79 (7)
F3—Nb1—F2^i	88.80 (3)	C1—C2—C3	112.53 (7)
F1—Nb1—F1^i	178.80 (2)	C1—C2—H2A	109.1
F3^i—Nb1—F1^i	86.19 (3)	C3—C2—H2A	109.1
F2—Nb1—F1^i	86.70 (3)	C1—C2—H2B	109.1
F3—Nb1—F1^i	86.30 (3)	C3—C2—H2B	109.1
F2^i—Nb1—F1^i	85.81 (3)	H2A—C2—H2B	107.8
F1—Nb1—O1^i	178.80 (2)	N1—C3—C2	111.81 (8)
F3^i—Nb1—O1^i	86.19 (3)	N1—C3—H3A	109.3
F2—Nb1—O1^i	86.70 (3)	C2—C3—H3A	109.3
F3—Nb1—O1^i	86.30 (3)	N1—C3—H3B	109.3
F2^i—Nb1—O1^i	85.81 (3)	C2—C3—H3B	109.3
C1—O3—H3	109.5	H3A—C3—H3B	107.9
H1—O4—H2	105.4 (14)
C1—C2—C3—N1	65.52 (10)	O2—C1—C2—C3	−8.02 (14)
O3—C1—C2—C3	172.70 (9)

Symmetry code: (i) −x+2, −y, −z+2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3···(F1/O1)^ii	0.83	1.79	2.6143 (9)	170
N1—H1A···O2	0.90	2.29	2.9159 (11)	126
N1—H1A···O4	0.90	2.37	3.0766 (12)	135
N1—H1A···O2^iii	0.90	2.45	2.8660 (10)	108
N1—H1B···F2^iv	0.90	2.04	2.8069 (10)	142
N1—H1C···O4^v	0.90	1.90	2.8019 (12)	175
O4—H1···(F1/O1)^v	0.761 (14)	1.979 (15)	2.7201 (9)	164.6 (15)
O4—H2···F3^vi	0.836 (16)	1.967 (16)	2.7923 (10)	168.9 (16)

Symmetry codes: (ii) −x+2, −y+1, −z+1; (iii) −x+1, −y+2, −z+1; (iv) −x+1, −y+1, −z+2; (v) −x+1, −y+1, −z+1; (vi) x, y+1, z−1.