Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536802015301/bt6185sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536802015301/bt6185Isup2.hkl |
CCDC reference: 198297
1 mmol (0.1717 g) of tetraethylammonium bromide, (Et4)NBr, and 3 mmol (0.8145 g) of mercuric bromide, HgBr2, were dissolved by stirring in 50 ml me thanol at 323 K until a clear solution was obtained. Single crystals were obtained when the solution was allowed to sit at room temperature for 2 d.
Data collection: X-AREA (Stoe & Cie, 2001); cell refinement: X-STEP (Stoe & Cie, 2000); data reduction: X-RED (Stoe & Cie, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 1999); software used to prepare material for publication: SHELXL97.
(C8H20N)2[Hg2Br6][HgBr2] | Dx = 3.044 Mg m−3 |
Mr = 1501.55 | Mo Kα radiation, λ = 0.71073 Å |
Tetragonal, P42/m | Cell parameters from 23650 reflections |
Hall symbol: -P4c | θ = 2.0–26.0° |
a = 10.0888 (11) Å | µ = 23.79 mm−1 |
c = 16.094 (2) Å | T = 293 K |
V = 1638.1 (3) Å3 | Prism, colourless |
Z = 2 | 0.2 × 0.15 × 0.1 mm |
F(000) = 1340 |
Stoe Imaging Plate Diffraction System (IPDS-I) diffractometer | 1681 independent reflections |
Radiation source: fine-focus sealed tube | 1114 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.116 |
ϕ scans | θmax = 26.0°, θmin = 2.0° |
Absorption correction: numerical (X-SHAPE; Stoe & Cie, 1998) | h = −12→12 |
Tmin = 0.023, Tmax = 0.093 | k = −12→11 |
23650 measured reflections | l = −19→19 |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.035 | H-atom parameters constrained |
wR(F2) = 0.088 | w = 1/[σ2(Fo2) + (0.0507P)2] where P = (Fo2 + 2Fc2)/3 |
S = 0.91 | (Δ/σ)max < 0.001 |
1681 reflections | Δρmax = 1.33 e Å−3 |
74 parameters | Δρmin = −0.84 e Å−3 |
0 restraints | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0087 (4) |
(C8H20N)2[Hg2Br6][HgBr2] | Z = 2 |
Mr = 1501.55 | Mo Kα radiation |
Tetragonal, P42/m | µ = 23.79 mm−1 |
a = 10.0888 (11) Å | T = 293 K |
c = 16.094 (2) Å | 0.2 × 0.15 × 0.1 mm |
V = 1638.1 (3) Å3 |
Stoe Imaging Plate Diffraction System (IPDS-I) diffractometer | 1681 independent reflections |
Absorption correction: numerical (X-SHAPE; Stoe & Cie, 1998) | 1114 reflections with I > 2σ(I) |
Tmin = 0.023, Tmax = 0.093 | Rint = 0.116 |
23650 measured reflections |
R[F2 > 2σ(F2)] = 0.035 | 0 restraints |
wR(F2) = 0.088 | H-atom parameters constrained |
S = 0.91 | Δρmax = 1.33 e Å−3 |
1681 reflections | Δρmin = −0.84 e Å−3 |
74 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
Hg1 | 0.46173 (6) | 0.18433 (6) | 0.0000 | 0.0584 (2) | |
Hg2 | 0.0000 | 0.5000 | 0.0000 | 0.0787 (3) | |
Br1 | 0.5000 | 0.0000 | 0.12403 (7) | 0.0530 (3) | |
Br2 | 0.65308 (14) | 0.34444 (14) | 0.0000 | 0.0533 (3) | |
Br3 | 0.21548 (16) | 0.23352 (17) | 0.0000 | 0.0667 (4) | |
Br4 | 0.0000 | 0.5000 | 0.14841 (8) | 0.0641 (4) | |
N1 | 0.0000 | 0.0000 | 0.2500 | 0.040 (3) | |
N2 | 0.5000 | 0.5000 | 0.2500 | 0.036 (3) | |
C1 | 0.1172 (11) | 0.1207 (10) | 0.3688 (6) | 0.059 (3) | |
H1C | 0.1169 | 0.2031 | 0.3987 | 0.071* | |
H1B | 0.2023 | 0.1079 | 0.3433 | 0.071* | |
H1A | 0.0998 | 0.0491 | 0.4066 | 0.071* | |
C2 | 0.0112 (13) | 0.1238 (11) | 0.3025 (8) | 0.070 (3) | |
H2B | 0.0286 | 0.1984 | 0.2660 | 0.084* | |
H2A | −0.0736 | 0.1396 | 0.3292 | 0.084* | |
C3 | 0.3207 (10) | 0.3232 (10) | 0.2369 (6) | 0.058 (2) | |
H3C | 0.2700 | 0.2752 | 0.1964 | 0.069* | |
H3B | 0.2619 | 0.3726 | 0.2721 | 0.069* | |
H3A | 0.3710 | 0.2620 | 0.2700 | 0.069* | |
C4 | 0.4135 (10) | 0.4167 (10) | 0.1935 (5) | 0.050 (2) | |
H4B | 0.3615 | 0.4757 | 0.1588 | 0.060* | |
H4A | 0.4705 | 0.3655 | 0.1571 | 0.060* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Hg1 | 0.0550 (4) | 0.0659 (4) | 0.0541 (3) | −0.0028 (3) | 0.000 | 0.000 |
Hg2 | 0.1267 (9) | 0.0680 (6) | 0.0413 (4) | −0.0128 (6) | 0.000 | 0.000 |
Br1 | 0.0653 (8) | 0.0571 (8) | 0.0367 (6) | −0.0011 (6) | 0.000 | 0.000 |
Br2 | 0.0550 (8) | 0.0563 (8) | 0.0487 (6) | −0.0023 (6) | 0.000 | 0.000 |
Br3 | 0.0546 (8) | 0.0776 (10) | 0.0678 (8) | 0.0149 (8) | 0.000 | 0.000 |
Br4 | 0.0817 (10) | 0.0676 (9) | 0.0430 (6) | −0.0007 (8) | 0.000 | 0.000 |
N1 | 0.033 (4) | 0.033 (4) | 0.055 (8) | 0.000 | 0.000 | 0.000 |
N2 | 0.036 (4) | 0.036 (4) | 0.034 (6) | 0.000 | 0.000 | 0.000 |
C1 | 0.060 (6) | 0.057 (6) | 0.061 (5) | −0.013 (5) | −0.001 (5) | −0.008 (5) |
C2 | 0.080 (8) | 0.050 (6) | 0.081 (7) | −0.001 (6) | 0.003 (6) | −0.013 (5) |
C3 | 0.051 (5) | 0.055 (6) | 0.066 (6) | −0.014 (5) | 0.003 (5) | 0.003 (5) |
C4 | 0.057 (5) | 0.049 (5) | 0.043 (4) | −0.012 (4) | −0.004 (4) | −0.006 (4) |
Hg1—Br2 | 2.5171 (16) | N1—C2iv | 1.513 (10) |
Hg1—Br3 | 2.5334 (17) | N1—C2v | 1.513 (10) |
Hg1—Br1i | 2.7553 (9) | N2—C4 | 1.515 (8) |
Hg1—Br1 | 2.7553 (9) | N2—C4vi | 1.515 (8) |
Hg2—Br4ii | 2.3885 (14) | N2—C4vii | 1.515 (8) |
Hg2—Br4 | 2.3885 (14) | N2—C4viii | 1.515 (8) |
Br1—Hg1i | 2.7553 (9) | C1—C2 | 1.511 (16) |
N1—C2 | 1.513 (10) | C3—C4 | 1.502 (13) |
N1—C2iii | 1.513 (10) | ||
Br2—Hg1—Br3 | 128.79 (6) | C2—N1—C2v | 108.2 (5) |
Br2—Hg1—Br1i | 109.00 (3) | C2iii—N1—C2v | 112.1 (10) |
Br3—Hg1—Br1i | 105.64 (3) | C2iv—N1—C2v | 108.2 (5) |
Br2—Hg1—Br1 | 109.00 (3) | C4—N2—C4vi | 106.2 (7) |
Br3—Hg1—Br1 | 105.64 (3) | C4—N2—C4vii | 111.1 (4) |
Br1i—Hg1—Br1 | 92.84 (4) | C4vi—N2—C4vii | 111.1 (4) |
Br4ii—Hg2—Br4 | 180.0 | C4—N2—C4viii | 111.1 (4) |
Hg1i—Br1—Hg1 | 87.16 (4) | C4vi—N2—C4viii | 111.1 (4) |
C2—N1—C2iii | 108.2 (5) | C4vii—N2—C4viii | 106.2 (7) |
C2—N1—C2iv | 112.1 (10) | C1—C2—N1 | 115.5 (9) |
C2iii—N1—C2iv | 108.2 (5) | C3—C4—N2 | 115.3 (7) |
Symmetry codes: (i) −x+1, −y, −z; (ii) −x, −y+1, −z; (iii) −y, x, −z+1/2; (iv) −x, −y, z; (v) y, −x, −z+1/2; (vi) −x+1, −y+1, z; (vii) −y+1, x, −z+1/2; (viii) y, −x+1, −z+1/2. |
Experimental details
Crystal data | |
Chemical formula | (C8H20N)2[Hg2Br6][HgBr2] |
Mr | 1501.55 |
Crystal system, space group | Tetragonal, P42/m |
Temperature (K) | 293 |
a, c (Å) | 10.0888 (11), 16.094 (2) |
V (Å3) | 1638.1 (3) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 23.79 |
Crystal size (mm) | 0.2 × 0.15 × 0.1 |
Data collection | |
Diffractometer | Stoe Imaging Plate Diffraction System (IPDS-I) diffractometer |
Absorption correction | Numerical (X-SHAPE; Stoe & Cie, 1998) |
Tmin, Tmax | 0.023, 0.093 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 23650, 1681, 1114 |
Rint | 0.116 |
(sin θ/λ)max (Å−1) | 0.617 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.035, 0.088, 0.91 |
No. of reflections | 1681 |
No. of parameters | 74 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 1.33, −0.84 |
Computer programs: X-AREA (Stoe & Cie, 2001), X-STEP (Stoe & Cie, 2000), X-RED (Stoe & Cie, 2001), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), DIAMOND (Brandenburg, 1999), SHELXL97.
Hg1—Br2 | 2.5171 (16) | N1—C2 | 1.513 (10) |
Hg1—Br3 | 2.5334 (17) | N2—C4 | 1.515 (8) |
Hg1—Br1 | 2.7553 (9) | C1—C2 | 1.511 (16) |
Hg2—Br4 | 2.3885 (14) | C3—C4 | 1.502 (13) |
Br2—Hg1—Br3 | 128.79 (6) | C2—N1—C2iii | 112.1 (10) |
Br2—Hg1—Br1 | 109.00 (3) | C2iii—N1—C2iv | 108.2 (5) |
Br3—Hg1—Br1 | 105.64 (3) | C4—N2—C4v | 106.2 (7) |
Br1i—Hg1—Br1 | 92.84 (4) | C4v—N2—C4vi | 111.1 (4) |
Br4ii—Hg2—Br4 | 180.0 | C1—C2—N1 | 115.5 (9) |
Hg1i—Br1—Hg1 | 87.16 (4) | C3—C4—N2 | 115.3 (7) |
Symmetry codes: (i) −x+1, −y, −z; (ii) −x, −y+1, −z; (iii) −x, −y, z; (iv) y, −x, −z+1/2; (v) −x+1, −y+1, z; (vi) −y+1, x, −z+1/2. |
The crystal structures of several halogenomercurates(II) have been reported and show a wide variety of stereochemical arrangements, as listed in a recent overview (Serezhkin et al., 2001). With simple cations, such as NH4+ or alkali metals, the `characteristic' coordination of mercury (Grdenić, 1965) is usually digonal, with Br—Hg—Br quasi-molecules. The coordination of mercury is then often completed to an `effective' [2 + 4] distorted octahedron, with two covalent bonds and four additional Br atoms which are significantly further away, but still within the sum of the van der Waals radii. A typical example is (NH4)4HgBr6 with isolated [2 + 4] octahedra of Br− surrounding Hg2+ (Nockemann & Meyer, 2001).
The crystal structure of (Et4N)2[Hg2Br6] contains isolated bitetrahedral [Hg2Br6]2− units consisting of two tetrahedra sharing one common edge (Nockemann & Meyer, 2002). Another compound in the (Et4N)Br/HgBr2 system is (Et4N)2[HgBr4], which consists of isolated [HgBr4]2− tetrahedra (Dean, Vittal & Wu, 1993).
The structure of (Et4N)2[Hg3Br8] or `(Et4N)2[Hg2Br6][HgBr2]', (I), consists of isolated bitetrahedral [Hg2Br6]2− units consisting of two tetrahedra sharing one common edge and further contains molecular digonal Br—Hg—Br units. The bitetrahedral [Hg2Br6]2− units exhibit two short bonds of 2.5171 (16) and 2.5334 (17) Å, and two long bonds to the bridging Br− ions of 2.7553 (9) Å. The coordination sphere of the diagonal Br—Hg—Br unit [Hg—Br 2.3885 (14) Å] is completed to a distorted octahedron with an `effective' [2 + 2+2] coordination by two long Hg···Br contacts of approximately 3.458 Å, and two very long Hg···Br contacts of approximately 3.836 Å, as shown in Fig. 2. In (Et4N)2[Hg3Br8] charge balance is achieved by ordered [Et4N]+ cations, which are located between the [Hg2Br6][HgBr2] layers. The distance between these layers amounts to half of the c axis.