Tetraamminehexabromodiscandium(III)

The title compound, [Sc₂Br₆(NH₃)₄], was obtained by the reaction of ammonium bromide, (NH₄)Br, with scandium metal in a sealed tantalum container. The crystal structure contains isolated dimers of bromide edge-connected [Sc-mer-(NH₃)₃Br₃] and [Sc(NH₃)Br₅] octahedra. Sc(NH₃)₂Br₃ is isotypic with Sc(NH₃)₂Cl₃.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](Sc-N) = 0.010 Å
• R factor = 0.039
• wR factor = 0.081
• Data-to-parameter ratio = 26.5

checkCIF/PLATON results

No syntax errors found



Alert level C
GOODF01_ALERT_2_C  The least squares goodness of fit parameter lies
            outside the range 0.80 <> 2.00
            Goodness of fit given =      0.700
PLAT041_ALERT_1_C Calc. and Rep. SumFormula Strings    Differ ....          ?
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ ....          ?
PLAT420_ALERT_2_C D-H Without Acceptor       N11    -   H11B   ...          ?
PLAT420_ALERT_2_C D-H Without Acceptor       N11    -   H11C   ...          ?
PLAT420_ALERT_2_C D-H Without Acceptor       N12    -   H12A   ...          ?
PLAT420_ALERT_2_C D-H Without Acceptor       N13    -   H13A   ...          ?
PLAT420_ALERT_2_C D-H Without Acceptor       N13    -   H13B   ...          ?
PLAT431_ALERT_2_C Short Inter HL..A Contact  Br1    ..  Br2      =       3.60 Ang.

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

   2 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
   0 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion

---

Computing details

Data collection: X-AREA (Stoe & Cie, 2002); cell refinement: X-AREA; data reduction: X-AREA; program(s) used to solve structure: SIR92 (Altomare et al., 1993); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 1996); software used to prepare material for publication: SHELXL97.

Tetraamminehexabromodiscandium(III)

Crystal data

[Sc2Br6(NH3)4]	Z = 2
Mr = 637.52	F(000) = 584
Triclinic, P1	Dx = 2.827 Mg m^−3
Hall symbol: -P 1	Melting point: unknown K
a = 7.211 (2) Å	Mo Kα radiation, λ = 0.71073 Å
b = 10.157 (3) Å	Cell parameters from 2678 reflections
c = 11.350 (3) Å	θ = 1.9–29.7°
α = 105.39 (2)°	µ = 16.88 mm^−1
β = 90.76 (2)°	T = 293 K
γ = 109.85 (2)°	Column, colourless
V = 749.0 (4) Å^3	0.2 × 0.1 × 0.1 mm

Data collection

Stoe IPDS II diffractometer	2938 independent reflections
Radiation source: fine-focus sealed tube	1237 reflections with I > 2s(I)
Graphite monochromator	Rint = 0.077
Detector resolution: not measured pixels mm^-1	θmax = 26.0°, θmin = 1.9°
ω and φ scans	h = −8→8
Absorption correction: numerical the absorption correction (X-RED; Stoe & Cie, 2001) was performed after optimizing the crystal shape using X-SHAPE (Stoe & Cie, 1999)	k = −12→12
Tmin = 0.100, Tmax = 0.148	l = −13→13
6953 measured reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.039	H-atom parameters constrained
wR(F^2) = 0.081	w = 1/[σ^2(Fo^2) + (0.0201P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 0.70	(Δ/σ)max < 0.001
2938 reflections	Δρmax = 0.66 e Å^−3
111 parameters	Δρmin = −0.70 e Å^−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 1997), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.00190 (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
Br21	0.1258 (2)	0.40251 (16)	0.34540 (12)	0.0546 (4)
Br11	−0.14637 (19)	−0.42322 (15)	0.13769 (11)	0.0521 (4)
Br1	−0.0130 (2)	−0.01176 (15)	0.24330 (12)	0.0481 (3)
Br2	0.5115 (2)	0.02968 (14)	0.25850 (12)	0.0486 (4)
Br23	0.33607 (19)	0.22062 (15)	0.53367 (11)	0.0511 (4)
Br22	0.3424 (2)	0.22896 (17)	0.07698 (11)	0.0558 (4)
Sc1	0.1727 (3)	−0.2021 (3)	0.1969 (2)	0.0415 (5)
Sc2	0.3187 (3)	0.2260 (3)	0.3042 (2)	0.0394 (5)
N13	0.1770 (14)	−0.1951 (11)	0.3998 (8)	0.052 (3)
H13A	0.2940	−0.1334	0.4400	0.117 (16)*
H13B	0.1576	−0.2840	0.4066	0.117 (16)*
H13C	0.0812	−0.1653	0.4317	0.117 (16)*
N11	0.1814 (14)	−0.1890 (11)	0.0005 (8)	0.051 (3)
H11A	0.3022	−0.1796	−0.0215	0.117 (16)*
H11B	0.1524	−0.1121	−0.0047	0.117 (16)*
H11C	0.0930	−0.2701	−0.0494	0.117 (16)*
N21	0.6158 (15)	0.3995 (11)	0.3506 (9)	0.052 (3)
H21A	0.6266	0.4603	0.3051	0.117 (16)*
H21B	0.7083	0.3593	0.3356	0.117 (16)*
H21C	0.6320	0.4487	0.4299	0.117 (16)*
N12	0.3669 (15)	−0.3404 (11)	0.1667 (8)	0.053 (3)
H12A	0.2912	−0.4341	0.1522	0.117 (16)*
H12B	0.4524	−0.3132	0.2335	0.117 (16)*
H12C	0.4334	−0.3283	0.1025	0.117 (16)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br21	0.0542 (9)	0.0524 (9)	0.0616 (8)	0.0289 (7)	0.0031 (6)	0.0107 (7)
Br11	0.0482 (8)	0.0467 (8)	0.0525 (7)	0.0078 (7)	0.0048 (6)	0.0116 (6)
Br1	0.0359 (6)	0.0443 (8)	0.0604 (8)	0.0142 (6)	0.0044 (5)	0.0090 (6)
Br2	0.0362 (6)	0.0433 (8)	0.0626 (8)	0.0160 (6)	0.0046 (5)	0.0068 (6)
Br23	0.0578 (8)	0.0577 (9)	0.0392 (6)	0.0215 (7)	0.0062 (6)	0.0148 (6)
Br22	0.0556 (8)	0.0706 (10)	0.0404 (7)	0.0194 (7)	0.0068 (6)	0.0185 (6)
Sc1	0.0406 (12)	0.0385 (13)	0.0446 (10)	0.0144 (10)	0.0057 (9)	0.0101 (10)
Sc2	0.0378 (11)	0.0396 (13)	0.0396 (10)	0.0141 (10)	0.0045 (8)	0.0090 (9)
N13	0.044 (6)	0.059 (7)	0.054 (6)	0.017 (5)	0.006 (5)	0.019 (5)
N11	0.050 (6)	0.049 (7)	0.047 (6)	0.012 (5)	0.004 (4)	0.010 (5)
N21	0.052 (7)	0.047 (6)	0.054 (6)	0.014 (5)	0.012 (5)	0.011 (5)
N12	0.067 (7)	0.045 (6)	0.058 (6)	0.035 (5)	0.013 (5)	0.013 (5)

Geometric parameters (Å, º)

Br21—Sc2	2.575 (3)	N13—H13A	0.8900
Br11—Sc1	2.538 (3)	N13—H13B	0.8900
Br1—Sc1	2.654 (3)	N13—H13C	0.8900
Br1—Sc2	2.679 (3)	N11—H11A	0.8900
Br2—Sc1	2.679 (3)	N11—H11B	0.8900
Br2—Sc2	2.745 (3)	N11—H11C	0.8900
Br23—Sc2	2.622 (3)	N21—H21A	0.8900
Br22—Sc2	2.594 (3)	N21—H21B	0.8900
Sc1—N11	2.269 (9)	N21—H21C	0.8900
Sc1—N12	2.269 (9)	N12—H12A	0.8900
Sc1—N13	2.284 (10)	N12—H12B	0.8900
Sc2—N21	2.211 (10)	N12—H12C	0.8900
Sc1—Br1—Sc2	95.35 (9)	Br21—Sc2—Br2	177.95 (11)
Sc1—Br2—Sc2	93.25 (8)	Br22—Sc2—Br2	87.55 (8)
N11—Sc1—N12	91.6 (4)	Br23—Sc2—Br2	87.06 (8)
N11—Sc1—N13	175.3 (4)	Br1—Sc2—Br2	84.79 (9)
N12—Sc1—N13	90.5 (3)	Sc1—N13—H13A	109.5
N11—Sc1—Br11	91.6 (3)	Sc1—N13—H13B	109.5
N12—Sc1—Br11	93.2 (3)	H13A—N13—H13B	109.5
N13—Sc1—Br11	92.4 (3)	Sc1—N13—H13C	109.5
N11—Sc1—Br1	89.0 (3)	H13A—N13—H13C	109.5
N12—Sc1—Br1	172.8 (3)	H13B—N13—H13C	109.5
N13—Sc1—Br1	88.4 (3)	Sc1—N11—H11A	109.5
Br11—Sc1—Br1	93.95 (9)	Sc1—N11—H11B	109.5
N11—Sc1—Br2	88.2 (3)	H11A—N11—H11B	109.5
N12—Sc1—Br2	86.3 (3)	Sc1—N11—H11C	109.5
N13—Sc1—Br2	87.7 (3)	H11A—N11—H11C	109.5
Br11—Sc1—Br2	179.43 (12)	H11B—N11—H11C	109.5
Br1—Sc1—Br2	86.61 (9)	Sc2—N21—H21A	109.5
N21—Sc2—Br21	95.2 (3)	Sc2—N21—H21B	109.5
N21—Sc2—Br22	87.9 (3)	H21A—N21—H21B	109.5
Br21—Sc2—Br22	92.64 (9)	Sc2—N21—H21C	109.5
N21—Sc2—Br23	87.8 (3)	H21A—N21—H21C	109.5
Br21—Sc2—Br23	92.89 (8)	H21B—N21—H21C	109.5
Br22—Sc2—Br23	173.27 (10)	Sc1—N12—H12A	109.5
N21—Sc2—Br1	171.6 (3)	Sc1—N12—H12B	109.5
Br21—Sc2—Br1	93.17 (9)	H12A—N12—H12B	109.5
Br22—Sc2—Br1	92.17 (9)	Sc1—N12—H12C	109.5
Br23—Sc2—Br1	91.35 (9)	H12A—N12—H12C	109.5
N21—Sc2—Br2	86.8 (3)	H12B—N12—H12C	109.5

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N13—H13A···Br23^i	0.89	3.12	3.690 (10)	124
N13—H13B···Br21^ii	0.89	3.00	3.854 (11)	161
N13—H13C···Br23^iii	0.89	2.92	3.722 (9)	151
N11—H11A···Br22^iv	0.89	2.82	3.684 (9)	163
N11—H11B···Br22	0.89	3.13	3.846 (11)	139
N21—H21A···Br11^v	0.89	2.77	3.514 (10)	143
N21—H21B···Br21^vi	0.89	2.89	3.669 (10)	148
N21—H21C···Br21^vii	0.89	2.81	3.609 (10)	151
N12—H12A···Br21^ii	0.89	3.11	3.712 (10)	127
N12—H12B···Br23^i	0.89	2.79	3.671 (10)	170
N12—H12C···Br22^iv	0.89	2.80	3.678 (9)	168

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