Synthesis and redetermination of the crystal structure of NbF5

Möbs, M.; Kraus, F.

doi:10.1107/S2056989023010150

Synthesis and redetermination of the crystal structure of NbF₅

NbF₅ was synthesized in high purity by direct fluorination. IR and Raman spectroscopy confirms the high purity. The crystal structure was redetermined at 100 K with higher precision.

Keywords: crystal structure; redetermination; niobium(V) fluoride; synthesis; powder X-ray diffraction.

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Supporting information

	Crystallographic Information File (CIF) https://doi.org/10.1107/S2056989023010150/ox2001sup1.cif Contains datablock I
	Structure factor file (CIF format) https://doi.org/10.1107/S2056989023010150/ox2001Isup2.hkl Contains datablock I
	Rietveld powder data file (CIF format) https://doi.org/10.1107/S2056989023010150/ox2001Isup3.rtv Contains datablock I
	Microsoft Word (DOCX) file https://doi.org/10.1107/S2056989023010150/ox2001sup4.docx IR and Raman spectra

CCDC references: 2309973; 2289431

checkCIF report

Key indicators

Structure: I

Single-crystal X-ray study
T = 100 K
Mean (b-F) = 0.001 Å
R factor = 0.014
wR factor = 0.032
Data-to-parameter ratio = 17.5

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT041_ALERT_1_C Calc. and Reported SumFormula    Strings  Differ     Please Check
              Calc: F5 Nb
              Rep.: F5 Nb1
PLAT911_ALERT_3_C Missing FCF Refl Between Thmin & STh/L=    0.600          5 Report
                2  2  0,  -1  3  1,  -3  5  1,  -2  0  2,   2  0  2,

Alert level G
FORMU01_ALERT_1_G  There is a discrepancy between the atom counts in the
            _chemical_formula_sum and _chemical_formula_moiety. This is
            usually due to the moiety formula being in the wrong format.
            Atom count from _chemical_formula_sum:   F5 Nb1
            Atom count from _chemical_formula_moiety:F20 Nb4
PLAT019_ALERT_1_G _diffrn_measured_fraction_theta_full/*_max < 1.0      0.998 Report
PLAT045_ALERT_1_G Calculated and Reported Z Differ by a Factor ...      0.250 Check
PLAT112_ALERT_2_G ADDSYM Detects New (Pseudo) Symm. Elem       sub         87 %Fit
PLAT112_ALERT_2_G ADDSYM Detects New (Pseudo) Symm. Elem       343         87 %Fit
PLAT434_ALERT_2_G Short Inter HL..HL Contact F1       ..F2       .       2.77 Ang.
                                                    x,y,1+z  =      1_556 Check
PLAT434_ALERT_2_G Short Inter HL..HL Contact F2       ..F2       .       2.63 Ang.
                                                    -x,y,-z  =      2_555 Check
PLAT434_ALERT_2_G Short Inter HL..HL Contact F2       ..F5       .       2.70 Ang.
                                                    -x,y,-z  =      2_555 Check
PLAT434_ALERT_2_G Short Inter HL..HL Contact F2       ..F5       .       2.70 Ang.
                                                   -x,-y,-z  =      5_555 Check
PLAT794_ALERT_5_G Tentative Bond Valency for Nb1       (V)       .       5.62 Info
PLAT794_ALERT_5_G Tentative Bond Valency for Nb2       (V)       .       5.63 Info
PLAT802_ALERT_4_G CIF Input Record(s) with more than 80 Characters          1 Info
PLAT899_ALERT_4_G SHELXL2018 is Deprecated and Succeeded by SHELXL     2019/3 Note
PLAT912_ALERT_4_G Missing # of FCF Reflections Above STh/L=  0.600          1 Note
PLAT913_ALERT_3_G Missing # of Very Strong Reflections in FCF ....          2 Note
               -3  5  1,   2  0  2,
PLAT933_ALERT_2_G Number of HKL-OMIT Records in Embedded .res File          1 Note
               -2  0  2,

   0 ALERT level A = Most likely a serious problem - resolve or explain
   0 ALERT level B = A potentially serious problem, consider carefully
   2 ALERT level C = Check. Ensure it is not caused by an omission or oversight
  16 ALERT level G = General information/check it is not something unexpected

   4 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   7 ALERT type 2 Indicator that the structure model may be wrong or deficient
   2 ALERT type 3 Indicator that the structure quality may be low
   3 ALERT type 4 Improvement, methodology, query or suggestion
   2 ALERT type 5 Informative message, check

Computing details top

Niobium(V) fluoride top

Crystal data top

Nb₄F₂₀	F(000) = 688
M_r = 187.91	D_x = 3.719 Mg m⁻³
Monoclinic, C2/m	Mo Kα radiation, λ = 0.71073 Å
a = 9.4863 (12) Å	Cell parameters from 8094 reflections
b = 14.2969 (12) Å	θ = 2.6–30.9°
c = 4.9892 (6) Å	µ = 3.56 mm⁻¹
β = 97.292 (10)°	T = 100 K
V = 671.19 (13) Å³	Block, colorless
Z = 8	0.18 × 0.05 × 0.05 mm

Data collection top

Stoe IPDSII diffractometer	1048 independent reflections
Radiation source: sealed X-ray tube, 12 x 0.4 mm long-fine focus	903 reflections with I > 2σ(I)
Detector resolution: 6.67 pixels mm^-1	R_int = 0.032
rotation method, ω scans	θ_max = 30.4°, θ_min = 2.6°
Absorption correction: numerical (X-RED32 and X-SHAPE; Stoe & Cie, Stoe & Cie, 2020)	h = −13→13
T_min = 0.776, T_max = 0.778	k = −18→20
5819 measured reflections	l = −7→7

Refinement top

Refinement on F²	0 restraints
Least-squares matrix: full	Primary atom site location: dual
R[F² > 2σ(F²)] = 0.014	Secondary atom site location: difference Fourier map
wR(F²) = 0.032	w = 1/[σ²(F_o²) + (0.0196P)²] where P = (F_o² + 2F_c²)/3
S = 1.02	(Δ/σ)_max = 0.001
1048 reflections	Δρ_max = 0.54 e Å⁻³
60 parameters	Δρ_min = −0.52 e Å⁻³

Special details top

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

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Nb1	0.000000	0.20347 (2)	0.500000	0.01085 (6)
Nb2	0.26047 (2)	0.000000	0.24168 (4)	0.01094 (6)
F1	0.34193 (16)	0.000000	0.6005 (3)	0.0169 (3)
F2	0.13043 (15)	0.000000	−0.0646 (3)	0.0148 (3)
F3	0.36790 (12)	0.09599 (7)	0.1443 (2)	0.0179 (2)
F4	0.12213 (11)	0.09546 (6)	0.3786 (2)	0.01482 (19)
F5	−0.10961 (12)	0.18505 (7)	0.17107 (19)	0.0163 (2)
F6	0.11939 (13)	0.28718 (7)	0.3733 (2)	0.0171 (2)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Nb1	0.01143 (11)	0.00957 (9)	0.01173 (9)	0.000	0.00212 (7)	0.000
Nb2	0.01106 (10)	0.01044 (9)	0.01157 (10)	0.000	0.00242 (7)	0.000
F1	0.0168 (7)	0.0195 (6)	0.0141 (6)	0.000	0.0011 (5)	0.000
F2	0.0145 (6)	0.0152 (6)	0.0145 (6)	0.000	0.0013 (5)	0.000
F3	0.0177 (5)	0.0169 (5)	0.0196 (5)	−0.0046 (4)	0.0043 (4)	0.0012 (4)
F4	0.0150 (4)	0.0130 (4)	0.0170 (4)	0.0021 (4)	0.0039 (3)	−0.0013 (4)
F5	0.0176 (5)	0.0163 (4)	0.0146 (4)	−0.0003 (4)	0.0008 (4)	−0.0004 (4)
F6	0.0175 (5)	0.0152 (4)	0.0189 (5)	−0.0026 (4)	0.0036 (4)	0.0018 (4)

Geometric parameters (Å, º) top

Nb1—F6	1.8157 (11)	Nb2—F3	1.8121 (10)
Nb1—F6ⁱ	1.8158 (10)	Nb2—F3ⁱⁱ	1.8122 (10)
Nb1—F5	1.8468 (10)	Nb2—F2	1.8378 (14)
Nb1—F5ⁱ	1.8468 (10)	Nb2—F1	1.8577 (14)
Nb1—F4ⁱ	2.0669 (9)	Nb2—F4	2.0685 (10)
Nb1—F4	2.0669 (9)	Nb2—F4ⁱⁱ	2.0685 (10)

F6—Nb1—F6ⁱ	97.52 (7)	F3—Nb2—F2	96.78 (5)
F6—Nb1—F5	95.18 (5)	F3ⁱⁱ—Nb2—F2	96.78 (5)
F6ⁱ—Nb1—F5	95.61 (5)	F3—Nb2—F1	94.53 (5)
F6—Nb1—F5ⁱ	95.61 (5)	F3ⁱⁱ—Nb2—F1	94.53 (5)
F6ⁱ—Nb1—F5ⁱ	95.18 (5)	F2—Nb2—F1	162.63 (6)
F5—Nb1—F5ⁱ	163.61 (7)	F3—Nb2—F4	89.47 (5)
F6—Nb1—F4ⁱ	172.83 (4)	F3ⁱⁱ—Nb2—F4	171.95 (4)
F6ⁱ—Nb1—F4ⁱ	89.59 (4)	F2—Nb2—F4	83.54 (5)
F5—Nb1—F4ⁱ	83.14 (5)	F1—Nb2—F4	83.43 (4)
F5ⁱ—Nb1—F4ⁱ	84.63 (4)	F3—Nb2—F4ⁱⁱ	171.95 (4)
F6—Nb1—F4	89.59 (4)	F3ⁱⁱ—Nb2—F4ⁱⁱ	89.47 (5)
F6ⁱ—Nb1—F4	172.83 (4)	F2—Nb2—F4ⁱⁱ	83.54 (5)
F5—Nb1—F4	84.62 (4)	F1—Nb2—F4ⁱⁱ	83.43 (4)
F5ⁱ—Nb1—F4	83.14 (5)	F4—Nb2—F4ⁱⁱ	82.57 (5)
F4ⁱ—Nb1—F4	83.32 (5)	Nb1—F4—Nb2	172.94 (5)
F3—Nb2—F3ⁱⁱ	98.46 (7)

Symmetry codes: (i) −x, y, −z+1; (ii) x, −y, z.

Selected crystallographic details for NbF₅ determined from single crystal X-ray diffraction (SCXRD, middle column) and powder X-ray diffraction (PXRD, Rietveld refinement, right column) top

	NbF₅ (SCXRD)	NbF₅ (PXRD)
Empirical formula	NbF₅	NbF₅
Empirical formula moiety	Nb₄F₂₀	Nb₄F₂₀
Color and appearance	colorless block	colorless powder
Size (mm³); capillary diameter (mm)	0.180 × 0.050 × 0.050	0.3
Molecular mass (g mol^–1)	187.91	187.91
Crystal system	monoclinic	monoclinic
Space group (No.)	C2/m (12)	C2/m (12)
Pearson symbol	mC48	mC48
a (Å)	9.4863 (12)	9.62749 (19)
b (Å)	14.2969 (12)	14.4564 (3)
c (Å)	4.9892 (6)	5.12831 (10)
β (°)	97.292 (10)	95.8243 (4)
V (Å³)	671.19 (13)	710.07 (3)
Z	8	8
Z'	2	2
ρ_calc (g cm^-3)	3.719	3.515
λ (Å)	0.71073 (Mo Kα)	1.540596 (Cu Kα₁)
T (K)	100	293
µ (mm^-1)	3.561	27.9495
2θ range measured (min, max, increment)	5.182, 60.76, –	6.885, 80.340, 0.015
2θ range refined (min, max)	–	10.005, 80.340
hkl_max	-13 ≤ h ≤ 13	0 ≤ h ≤ 8
	-18 ≤ k ≤ 18	0 ≤ k ≤ 12
	-7≤ l ≤7	-4≤ l ≤4
Absorption correction	numerical	cylindrical
T_max, T_min	0.7778, 0.7760	–
R_int, R_σ	0.0318, 0.0172	–
Completeness	0.994	–
No. of unique reflections	1048	240
No. of parameters	60	74
No. of restraints	0	0
No. of constraints	0	0
Background parameters	–	20
Profile parameters	–	12^a
R_p, R_wp	–	0.0308, 0.0425
R_p^b, R_wp^b	–	0.0889, 0.0904
R_Bragg	–	0.0132
S (all data)	1.024	1.77
R(F) [I ≥ 2σ(I), all data]	0.0143, 0.0198	–
wR(F²) [I ≥ 2σ(I), all data]	0.0315, 0.0323	–
Δρ_max, Δρ_min (e Å^-3)	0.544, –0.521	–

Notes: (a) refined profile parameters include spherical harmonics of order 4; (b) background-corrected R-factors.

Selected interatomic distances (Å) for the crystal structure of NbF₅ top

Nb1—F4	2.0669 (9)	Nb2—F3	1.8121 (10)
Nb1—F5	1.8468 (10)	Nb2—F4	2.0685 (10)
Nb1—F6	1.8157 (11)	Nb1—Nb2	4.1275 (4)
Nb2—F1	1.8577 (14)	Nb1—Nb1ⁱⁱⁱ	5.8179 (6)
Nb2—F2	1.8378 (14)	Nb2—Nb2ⁱⁱ	5.8565 (8)

Symmetry codes: (i) x, -y, z; (ii) -x, y, 1 - z, (iii) -x, -y, 1 - z.

Selected interatomic angles (°) for the crystal structure of NbF₅. top

F6—Nb1—F6ⁱⁱ	97.52 (7)	F3—Nb2—F3ⁱ	98.46 (7)
F6—Nb1—F5	95.18 (5)	F3—Nb2—F2	96.78 (5)
F6ⁱ—Nb1—F5	95.61 (5)	F3ⁱ—Nb2—F2	96.78 (5)
F6—Nb1—F5ⁱⁱ	95.61 (5)	F3—Nb2—F1	94.53 (5)
F6ⁱⁱ—Nb1—F5ⁱⁱ	95.18 (5)	F3ⁱ—Nb2—F1	94.53 (5)
F5—Nb1—F5ⁱⁱ	163.61 (7)	F2—Nb2—F1	162.63 (6)
F6—Nb1—F4ⁱⁱ	172.83 (4)	F3—Nb2—F4	89.47 (5)
F6ⁱⁱ—Nb1—F4ⁱⁱ	89.59 (4)	F3ⁱ—Nb2—F4	171.95 (4)
F5—Nb1—F4ⁱⁱ	83.14 (5)	F2—Nb2—F4	83.54 (5)
F5ⁱⁱ—Nb1—F4ⁱⁱ	84.63 (4)	F1—Nb2—F4	83.43 (4)
F6—Nb1—F4	89.59 (4)	F3—Nb2—F4ⁱ	171.95 (4)
F6ⁱⁱ—Nb1—F4	172.83 (4)	F3ⁱ—Nb2—F4ⁱ	89.47 (5)
F5—Nb1—F4	84.62 (4)	F2—Nb2—F4ⁱ	83.54 (5)
F5ⁱⁱ—Nb1—F4	83.14 (5)	F1—Nb2—F4ⁱ	83.43 (4)
F4ⁱⁱ—Nb1—F4	83.32 (5)	F4—Nb2—F4ⁱ	82.57 (5)
Nb1—Nb2—Nb1ⁱⁱⁱ	89.62 (1)	Nb1—F4—Nb2	172.94 (5)
Nb2—Nb1—Nb2ⁱⁱ	90.38 (1)

Symmetry codes: (i) x, -y, z; (ii) -x, y, 1 - z, (iii) -x, -y, 1 - z.

Selected interatomic angles (°) for the crystal structure of NbF₅ top

F6ⁱ—Nb1—F5	95.61 (5)	F3ⁱ—Nb2—F2	96.78 (5)
F6—Nb1—F6ⁱⁱ	97.52 (7)	F3—Nb2—F3ⁱ	98.46 (7)
F6—Nb1—F5	95.18 (5)	F3—Nb2—F2	96.78 (5)
F6ⁱ—Nb1—F5	95.61 (5)	F3ⁱ—Nb2—F2	96.78 (5)
F6—Nb1—F5ⁱⁱ	95.61 (5)	F3—Nb2—F1	94.53 (5)
F6ⁱⁱ—Nb1—F5ⁱⁱ	95.18 (5)	F3ⁱ—Nb2—F1	94.53 (5)
F5—Nb1—F5ⁱⁱ	163.61 (7)	F2—Nb2—F1	162.63 (6)
F6—Nb1—F4ⁱⁱ	172.83 (4)	F3—Nb2—F4	89.47 (5)
F6ⁱⁱ—Nb1—F4ⁱⁱ	89.59 (4)	F3ⁱ—Nb2—F4	171.95 (4)
F5—Nb1—F4ⁱⁱ	83.14 (5)	F2—Nb2—F4	83.54 (5)
F5ⁱⁱ—Nb1—F4ⁱⁱ	84.63 (4)	F1—Nb2—F4	83.43 (4)
F6—Nb1—F4	89.59 (4)	F3—Nb2—F4ⁱ	171.95 (4)
F6ⁱⁱ—Nb1—F4	172.83 (4)	F3ⁱ—Nb2—F4ⁱ	89.47 (5)
F5—Nb1—F4	84.62 (4)	F2—Nb2—F4ⁱ	83.54 (5)
F5ⁱⁱ—Nb1—F4	83.14 (5)	F1—Nb2—F4ⁱ	83.43 (4)
F4ⁱⁱ—Nb1—F4	83.32 (5)	F4—Nb2—F4ⁱ	82.57 (5)
Nb1—Nb2—Nb1ⁱⁱⁱ	89.62 (1)	Nb1—F4—Nb2	172.94 (5)
Nb2—Nb1—Nb2ⁱⁱ	90.38 (1)

Symmetry codes: (i) x, -y, z; (ii) -x, y, 1 - z, (iii) -x, -y, 1 - z.

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