Niobium selenide trichloride, NbSeCl₃

The structure of the title compound, NbSeCl₃, was determined by single-crystal X-ray diffraction. The structure consists of NbSeCl₃ chains centred on the Nb atoms. These chains, with a zigzag development along the c direction, show a regular alternation of short and long Nb-Nb distances. NbSeCl₃ is isostructural with NbSeBr₃; it may be described as 2(Nb⁴⁺) (Se₂^2-) 6(Cl^-), with the presence of both (Nb-Nb)⁸⁺ and (Se-Se)^2- dimers.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](e-Se) = 0.001 Å
• R factor = 0.039
• wR factor = 0.073
• Data-to-parameter ratio = 37.5

checkCIF/PLATON results

No syntax errors found



Alert level B
RINTA01_ALERT_3_B  The value of Rint is greater than 0.15
            Rint given   0.161
PLAT020_ALERT_3_B The value of Rint is greater than 0.10 .........       0.16

Alert level C
PLAT041_ALERT_1_C Calc. and Rep. SumFormula Strings    Differ ....          ?
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ ....          ?
PLAT045_ALERT_1_C Calculated and Reported Z Differ by ............       0.50 Ratio
PLAT199_ALERT_1_C Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_C Check the Reported _diffrn_ambient_temperature .        293 K

   0 ALERT level A = In general: serious problem
   2 ALERT level B = Potentially serious problem
   5 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   5 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 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
   0 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: Please provide missing details; cell refinement: DIRAX (Duisenberg, 1992); data reduction: Please provide missing details; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 2001); software used to prepare material for publication: SHELXTL (Sheldrick, 2001).

Niobium selenide trichloride

Crystal data

NbSeCl3	F(000) = 504
Mr = 278.22	Dx = 3.692 Mg m^−3
Monoclinic, P2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yc	Cell parameters from 29 reflections
a = 6.2993 (13) Å	θ = 5.1–21.4°
b = 6.7205 (13) Å	µ = 11.09 mm^−1
c = 11.962 (2) Å	T = 293 K
β = 98.71 (3)°	Ribbon-shaped, dark-red
V = 500.56 (17) Å^3	0.22 × 0.04 × 0.02 mm
Z = 4

Data collection

Nonius KappaCCD area-detector diffractometer	1725 independent reflections
Radiation source: fine-focus sealed tube	1251 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.161
CCD scans	θmax = 32.0°, θmin = 6.5°
Absorption correction: gaussian integration (Reference?)	h = −9→8
Tmin = 0.157, Tmax = 0.839	k = −9→10
10058 measured reflections	l = −17→17

Refinement

Refinement on F^2	0 restraints
Least-squares matrix: full	Primary atom site location: structure-invariant direct methods
R[F^2 > 2σ(F^2)] = 0.039	Secondary atom site location: difference Fourier map
wR(F^2) = 0.073	w = 1/[σ^2(Fo^2) + (0.0233P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 0.99	(Δ/σ)max < 0.001
1725 reflections	Δρmax = 1.36 e Å^−3
46 parameters	Δρmin = −1.35 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
Nb1	0.07292 (6)	0.35745 (6)	0.14548 (3)	0.01460 (10)
Se1	−0.17021 (8)	0.07522 (8)	0.19917 (3)	0.02253 (12)
Cl1	0.35647 (18)	0.2079 (2)	0.06792 (8)	0.0274 (3)
Cl2	−0.24703 (16)	0.55253 (18)	0.19563 (7)	0.0189 (2)
Cl3	0.15715 (17)	0.67894 (18)	0.04371 (7)	0.0203 (2)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Nb1	0.01942 (17)	0.0149 (2)	0.00983 (15)	−0.00017 (16)	0.00327 (11)	−0.00050 (13)
Se1	0.0329 (3)	0.0174 (3)	0.01694 (19)	−0.0066 (2)	0.00256 (16)	−0.00091 (17)
Cl1	0.0258 (5)	0.0345 (7)	0.0234 (5)	0.0065 (5)	0.0085 (4)	−0.0013 (5)
Cl2	0.0229 (5)	0.0196 (6)	0.0141 (4)	0.0039 (4)	0.0021 (3)	0.0008 (4)
Cl3	0.0270 (5)	0.0210 (6)	0.0125 (4)	−0.0064 (4)	0.0016 (3)	0.0010 (4)

Geometric parameters (Å, º)

Nb1—Cl1	2.3587 (12)	Nb1—Se1^i	2.6610 (7)
Nb1—Cl2^i	2.4296 (12)	Nb1—Nb1^i	2.7913 (9)
Nb1—Cl3^ii	2.5077 (12)	Se1—Se1^i	2.2995 (12)
Nb1—Cl2	2.5508 (12)	Se1—Nb1^i	2.6610 (7)
Nb1—Cl3	2.5744 (12)	Cl2—Nb1^i	2.4296 (12)
Nb1—Se1	2.5795 (7)	Cl3—Nb1^ii	2.5078 (13)
Cl1—Nb1—Cl2^i	104.99 (4)	Cl3^ii—Nb1—Se1^i	126.96 (4)
Cl1—Nb1—Cl3^ii	88.40 (4)	Cl2—Nb1—Se1^i	107.99 (3)
Cl2^i—Nb1—Cl3^ii	152.79 (4)	Cl3—Nb1—Se1^i	152.41 (3)
Cl1—Nb1—Cl2	169.70 (4)	Se1—Nb1—Se1^i	52.03 (3)
Cl2^i—Nb1—Cl2	79.51 (5)	Cl1—Nb1—Nb1^i	136.37 (4)
Cl3^ii—Nb1—Cl2	83.86 (4)	Cl2^i—Nb1—Nb1^i	58.00 (3)
Cl1—Nb1—Cl3	87.09 (5)	Cl3^ii—Nb1—Nb1^i	125.78 (3)
Cl2^i—Nb1—Cl3	79.40 (4)	Cl2—Nb1—Nb1^i	53.88 (3)
Cl3^ii—Nb1—Cl3	77.73 (4)	Cl3—Nb1—Nb1^i	122.88 (2)
Cl2—Nb1—Cl3	84.64 (4)	Se1—Nb1—Nb1^i	59.244 (19)
Cl1—Nb1—Se1	107.34 (4)	Se1^i—Nb1—Nb1^i	56.408 (16)
Cl2^i—Nb1—Se1	114.63 (3)	Se1^i—Se1—Nb1	65.81 (2)
Cl3^ii—Nb1—Se1	82.48 (3)	Se1^i—Se1—Nb1^i	62.16 (2)
Cl2—Nb1—Se1	78.42 (3)	Nb1—Se1—Nb1^i	64.35 (2)
Cl3—Nb1—Se1	155.17 (3)	Nb1^i—Cl2—Nb1	68.12 (3)
Cl1—Nb1—Se1^i	82.11 (4)	Nb1^ii—Cl3—Nb1	102.27 (4)
Cl2^i—Nb1—Se1^i	79.01 (3)

Symmetry codes: (i) −x, y, −z+1/2; (ii) −x, −y+1, −z.