Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270199013700/br1266sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270199013700/br1266Isup2.hkl |
Single crystals of Rb4SnO4 were formed by the reduction of a mixture of RbO2 and SnO with elemental rubidium. Liquid rubidium (756.9 mg, 8.856 mmol; Maassen, 99°) was reacted with RbO2 (346.8 mg, 2.952 mmol) and powdered SnO (399.3 mg, 2.965 mmol; ABCR, 99°) in corundum crucibles under an argon atmosphere. The mixtures were heated up to 1000 K within 5 h and cooled to room temperature at a rate of 4 K/h. The thick honey-yellow hygroscopic crystals of the title compound were handled in a dry box and prepared in capillaries filled with dried oil. The X-ray powder pattern of the sample could be indexed on the basis of the reported single-crystal data of Rb4SnO4 but show additional reflections of Rb2SnO2 (Braun & Hoppe, 1982). The room-temperature Raman spectrum of a single-crystal sealed in a Lindemann capillary was recorded with a Raman microscope attached to an FT spectrometer (Bruker IFS66V).
Data collection: CAD-4 Software (Enraf-Nonius, 1989); cell refinement: CAD-4 Software; data reduction: HELENA (Spek, 1993); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP (Johnson, 1968) and DRAWxtl (Finger & Kroeker, 1997); software used to prepare material for publication: SHELXL97.
Rb4SnO4 | Z = 2 |
Mr = 524.57 | F(000) = 460 |
Triclinic, P1 | Dx = 4.312 Mg m−3 |
a = 6.773 (2) Å | Mo Kα radiation, λ = 0.71070 Å |
b = 6.776 (3) Å | Cell parameters from 25 reflections |
c = 10.122 (3) Å | θ = 7.3–21.4° |
α = 71.72 (3)° | µ = 27.05 mm−1 |
β = 79.48 (2)° | T = 293 K |
γ = 66.64 (2)° | Plate, pale yellow |
V = 404.0 (2) Å3 | 0.10 × 0.07 × 0.04 mm |
Enraf-Nonius CAD-4 diffractometer | Rint = 0.049 |
Radiation source: fine-focus sealed tube | θmax = 26°, θmin = 5.2° |
Graphite monochromator | h = 0→8 |
ω/2θ scans | k = −7→8 |
Absorption correction: ψ-scan (North et al., 1968) | l = −12→12 |
Tmin = 0.109, Tmax = 0.339 | 3 standard reflections every 120 min |
1710 measured reflections | intensity decay: none |
1575 independent reflections |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.056 | w = 1/[σ2(Fo2) + (0.1006P)2 + 1.5556P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.150 | (Δ/σ)max < 0.001 |
S = 1.10 | Δρmax = 4.13 e Å−3 |
1575 reflections | Δρmin = −4.37 e Å−3 |
83 parameters | Extinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
0 restraints | Extinction coefficient: 0.0139 (17) |
Rb4SnO4 | γ = 66.64 (2)° |
Mr = 524.57 | V = 404.0 (2) Å3 |
Triclinic, P1 | Z = 2 |
a = 6.773 (2) Å | Mo Kα radiation |
b = 6.776 (3) Å | µ = 27.05 mm−1 |
c = 10.122 (3) Å | T = 293 K |
α = 71.72 (3)° | 0.10 × 0.07 × 0.04 mm |
β = 79.48 (2)° |
Enraf-Nonius CAD-4 diffractometer | 1575 independent reflections |
Absorption correction: ψ-scan (North et al., 1968) | Rint = 0.049 |
Tmin = 0.109, Tmax = 0.339 | 3 standard reflections every 120 min |
1710 measured reflections | intensity decay: none |
R[F2 > 2σ(F2)] = 0.056 | 83 parameters |
wR(F2) = 0.150 | 0 restraints |
S = 1.10 | Δρmax = 4.13 e Å−3 |
1575 reflections | Δρmin = −4.37 e Å−3 |
Experimental. Absorption correction based on 12 psi-scans (North et al., 1968) |
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 | ||
Sn | 0.27370 (12) | 0.15660 (13) | 0.24574 (8) | 0.0127 (3) | |
O1 | 0.0399 (13) | 0.3022 (14) | 0.3713 (10) | 0.0212 (19) | |
O2 | 0.4593 (13) | 0.3337 (15) | 0.1882 (9) | 0.0206 (19) | |
O3 | 0.4475 (15) | −0.1437 (14) | 0.3495 (10) | 0.025 (2) | |
O4 | 0.1293 (18) | 0.158 (2) | 0.0971 (11) | 0.038 (3) | |
Rb1 | −0.2378 (2) | 0.2392 (2) | −0.03146 (14) | 0.0250 (4) | |
Rb2 | 0.27554 (19) | 0.5094 (2) | 0.44200 (13) | 0.0195 (4) | |
Rb3 | −0.2156 (2) | 0.0329 (2) | 0.37954 (14) | 0.0233 (4) | |
Rb4 | −0.2620 (2) | −0.4067 (2) | 0.16385 (14) | 0.0260 (4) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Sn | 0.0129 (5) | 0.0105 (5) | 0.0159 (5) | −0.0067 (3) | −0.0009 (3) | −0.0018 (3) |
O1 | 0.014 (4) | 0.017 (4) | 0.032 (5) | −0.002 (4) | −0.003 (4) | −0.009 (4) |
O2 | 0.015 (4) | 0.019 (4) | 0.028 (5) | −0.010 (4) | 0.006 (4) | −0.005 (4) |
O3 | 0.029 (5) | 0.011 (4) | 0.032 (5) | −0.010 (4) | 0.004 (4) | −0.004 (4) |
O4 | 0.044 (6) | 0.052 (7) | 0.030 (6) | −0.025 (6) | −0.006 (5) | −0.014 (5) |
Rb1 | 0.0229 (7) | 0.0199 (7) | 0.0283 (8) | −0.0026 (5) | −0.0054 (6) | −0.0057 (5) |
Rb2 | 0.0197 (6) | 0.0196 (7) | 0.0243 (7) | −0.0117 (5) | 0.0020 (5) | −0.0089 (5) |
Rb3 | 0.0234 (7) | 0.0215 (7) | 0.0261 (7) | −0.0124 (5) | −0.0076 (5) | 0.0013 (5) |
Rb4 | 0.0263 (7) | 0.0258 (7) | 0.0279 (8) | −0.0133 (6) | −0.0043 (6) | −0.0033 (5) |
Sn—O4 | 1.934 (10) | Rb2—O2 | 3.024 (9) |
Sn—O3 | 1.959 (9) | Rb3—O2iii | 2.877 (9) |
Sn—O2 | 1.962 (8) | Rb3—O1vii | 2.880 (9) |
Sn—O1 | 1.977 (9) | Rb3—O1 | 2.947 (8) |
Rb1—O4i | 2.758 (11) | Rb3—O3vii | 3.056 (9) |
Rb1—O2ii | 2.773 (9) | Rb3—O3iii | 3.063 (9) |
Rb1—O2iii | 2.783 (8) | Rb4—O4i | 2.858 (11) |
Rb1—O4 | 2.797 (11) | Rb4—O1viii | 2.873 (9) |
Rb2—O1iv | 2.764 (9) | Rb4—O3iii | 2.924 (9) |
Rb2—O1 | 2.802 (8) | Rb4—O2ix | 2.985 (9) |
Rb2—O3v | 2.855 (9) | Rb4—O4viii | 3.252 (12) |
Rb2—O3vi | 2.932 (10) | ||
O4—Sn—O3 | 113.4 (4) | O4—Sn—O1 | 105.1 (4) |
O4—Sn—O2 | 115.1 (4) | O3—Sn—O1 | 109.8 (4) |
O3—Sn—O2 | 107.3 (4) | O2—Sn—O1 | 105.7 (3) |
Symmetry codes: (i) −x, −y, −z; (ii) −x, −y+1, −z; (iii) x−1, y, z; (iv) −x, −y+1, −z+1; (v) x, y+1, z; (vi) −x+1, −y, −z+1; (vii) −x, −y, −z+1; (viii) x, y−1, z; (ix) x−1, y−1, z. |
Experimental details
Crystal data | |
Chemical formula | Rb4SnO4 |
Mr | 524.57 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 293 |
a, b, c (Å) | 6.773 (2), 6.776 (3), 10.122 (3) |
α, β, γ (°) | 71.72 (3), 79.48 (2), 66.64 (2) |
V (Å3) | 404.0 (2) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 27.05 |
Crystal size (mm) | 0.10 × 0.07 × 0.04 |
Data collection | |
Diffractometer | Enraf-Nonius CAD-4 diffractometer |
Absorption correction | ψ-scan (North et al., 1968) |
Tmin, Tmax | 0.109, 0.339 |
No. of measured, independent and observed (?) reflections | 1710, 1575, ? |
Rint | 0.049 |
(sin θ/λ)max (Å−1) | 0.617 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.056, 0.150, 1.10 |
No. of reflections | 1575 |
No. of parameters | 83 |
Δρmax, Δρmin (e Å−3) | 4.13, −4.37 |
Computer programs: CAD-4 Software (Enraf-Nonius, 1989), CAD-4 Software, HELENA (Spek, 1993), SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), ORTEP (Johnson, 1968) and DRAWxtl (Finger & Kroeker, 1997), SHELXL97.
Sn—O4 | 1.934 (10) | Rb2—O2 | 3.024 (9) |
Sn—O3 | 1.959 (9) | Rb3—O2iii | 2.877 (9) |
Sn—O2 | 1.962 (8) | Rb3—O1vii | 2.880 (9) |
Sn—O1 | 1.977 (9) | Rb3—O1 | 2.947 (8) |
Rb1—O4i | 2.758 (11) | Rb3—O3vii | 3.056 (9) |
Rb1—O2ii | 2.773 (9) | Rb3—O3iii | 3.063 (9) |
Rb1—O2iii | 2.783 (8) | Rb4—O4i | 2.858 (11) |
Rb1—O4 | 2.797 (11) | Rb4—O1viii | 2.873 (9) |
Rb2—O1iv | 2.764 (9) | Rb4—O3iii | 2.924 (9) |
Rb2—O1 | 2.802 (8) | Rb4—O2ix | 2.985 (9) |
Rb2—O3v | 2.855 (9) | Rb4—O4viii | 3.252 (12) |
Rb2—O3vi | 2.932 (10) | ||
O4—Sn—O3 | 113.4 (4) | O4—Sn—O1 | 105.1 (4) |
O4—Sn—O2 | 115.1 (4) | O3—Sn—O1 | 109.8 (4) |
O3—Sn—O2 | 107.3 (4) | O2—Sn—O1 | 105.7 (3) |
Symmetry codes: (i) −x, −y, −z; (ii) −x, −y+1, −z; (iii) x−1, y, z; (iv) −x, −y+1, −z+1; (v) x, y+1, z; (vi) −x+1, −y, −z+1; (vii) −x, −y, −z+1; (viii) x, y−1, z; (ix) x−1, y−1, z. |
Rb4SnO4 crystallizes in the triclinic spacegroup P1 and is isotypic with the Na4CoO4 structure type (Jansen, 1975). Corresponding alkaline metal oxotetrelates(IV) with the same structure type are the stannates K4SnO4 (Marchand et al., 1975) and Cs4SnO4 (Bernet & Hoppe, 1990), the plumbates of Na, K and Rb (Brandes & Hoppe, 1994; Nowitzki & Hoppe, 1983) the germanates of Na and K (Halwax & Völlenkle, 1985) and Na4SiO4 (Baur et al., 1986).
The Sn atoms in Rb4SnO4 are coordinated by four O atoms in a slightly distorted tetrahedral environment, with Sn—O distances ranging from 1.934 (10)? to 1.977 (9) Å and O—Sn—O angles from 105.1 (4) to 115.1 (4)°. As in all stannates of the type A4SnO3 and A4SnO4 (A = alkaline metal), all the O ligands are coordinated by five alkali metal atoms and one Sn atom in a distorted octahedral geometry (Fig. 1). The Sn—O distances in the title compound are thus comparable with those observed in the stannates(IV) K4SnO4 (Sn—O 1.95–1.96 Å) or Cs4SnO4 (Sn—O 1.94–1.97 Å) and they differ significantly from those observed in the stannates(II) K4SnO3 (Sn—O 2.041–2.052 Å; Röhr, 1995) or Cs4SnO3 (Sn—O 2.028–2.049 Å; Röhr & Zönnchen, 1998).
A view of the unit cell of Rb4SnO4 is given in Fig. 2. The coordination numbers of the Rb cations vary from 4 (Rb1) to 4 + 1 (Rb4) and 5 (Rb2, Rb3). A similar description of the packing as given for Cs4PbO4 (Müller et al., 1991) or Cs4SnO3 (Röhr & Zönnchen, 1998) is also possible for Rb4SnO4: Rb and Sn atoms together form planes of nearly hexagonal close-packed layers running perpendicular to the [100] direction. These layers are stacked in the sequence A—B, where the stacking is in between the hexagonal closed-packed arrangement and the α-U structure type observed for the packing of Cs and Sn in Cs4SnO3 (Fig. 3).
The Raman spectrum of Rb4SnO4 recorded at room temperature shows four bands that can be assigned to the four normal modes of an ideal tetrahedron XY4. The totally symmetric stretching mode (ν1, A1) is observed at 638 cm−1 and the asymmetric stretching mode (ν3, F2) is observed as a weak band at 620 cm−1. The symmetric (ν2, E) and the antisymmetric (ν4, F2) bending modes are observed at 188 cm−1 and 137 cm−1, respectively. This assignment is consistent in the series of MO4 silicates, germanates and stannates (Nyquist & Kagel, 1997).