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Triruthenium heptatin, Ru3Sn7, is an example of a body-centered cubic structure that can be described with two interpenetrating similar networks of slightly distorted square-antiprism Ru-Sn polyhedra. Each network can be modeled as dimers of face-sharing Ru-Sn square-antiprism polyhedra connected to each other with the square face. These barrel-like dimers make up one of the two networks. The barrels are connected to each other by the edge of the outer square face. The two interpenetrating networks are connected via the central corner Sn atoms of each dimer.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536801014246/br6028sup1.cif
Contains datablocks I, RS1

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536801014246/br6028Isup2.hkl
Contains datablock I

Key indicators

  • Single-crystal X-ray study
  • T = 293 K
  • Mean [sigma](Ru-Ru) = 0.002 Å
  • R factor = 0.030
  • wR factor = 0.045
  • Data-to-parameter ratio = 10.2

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


Yellow Alert Alert Level C:
GOODF_01 Alert C The least squares goodness of fit parameter lies outside the range 0.80 <> 2.00 Goodness of fit given = 2.510
0 Alert Level A = Potentially serious problem
0 Alert Level B = Potential problem
1 Alert Level C = Please check

Comment top

The title compound was synthesized as part of a reinvestigation of the Ru–Sn binary system. Earlier reports (Nial, 1947) of this compound were based on visually estimated intensities from powder data and only approximate structural parameters were determined. Ru3Sn7 is an example of an electron-rich compound (Häusserman et al., 1998) in the Ru/Sn system. The structure is built of square-face-sharing dimers of square antiprisms of Ru–Sn polyhedra (Fig. 1). These barrel-like dimers are, in turn, connected via edges of the outer square faces, occupied by Sn1, to each other giving one of the two component networks. The quadratic faces of six barrels make up an empty cube at the corner of the unit cell. The two equivalent interpenetrating frameworks (Fig. 2) are related by the I-centering condition and are connected to each other with the corner-shared Sn2 atom. The valence electron concentration (VEC) of the title compound is 52 electrons per formula unit. Several isomorphous T3E7 compounds (T is a transition metal and E is an electron-rich main group element) are known with VEC ranging from 51 to 55. The improved accuracy of parameters of the structural model may imply slight changes to the interpretation of the bonding situation in similar compounds. Doping of the title compound, both with neighbouring transition metals and electron-rich main group elements will be attempted in future experiments in order to elucidate the possibilities for affecting electronic properties.

Experimental top

The title compound was crystallized from a solid-state reaction between a 1:10 mixture of Ru and Sn. The mixture was heated in an evacuated quartz ampoule at 973 K for 24 h and let to cool to room temperature over a period of approximately 1 h. Small crystals of the title compound were found in a matrix of Sn. The excess Sn was removed by treatment with NaOH aqueous solution, 2 mol dm-3.

Refinement top

The maximum residual electron density was located at (0.1229, 0, 0.1229), 1.59 Å from Sn2, and the minimum residual density was located at (0, 0, 0), 2.61 Å from Sn2. None of these residual densities were interpreted as anything other than artefacts, perhaps occurring due to the high symmetry of these positions. The lattice parameter from the single-crystal experiment were checked by powder diffraction methods with a Guinier-Hägg camera using Si as internal standard for the 2θ scale giving a value of the unit-cell edge a = 9.3533 (4) Å, well in accordance with the value estimated from the IPDS measurements.

Computing details top

Data collection: EXPOSE in IPDS (Stoe & Cie, 1997); cell refinement: CELL in IPDS; data reduction: X-RED (Stoe & Cie, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Bergerhoff, 1996).

Figures top
[Figure 1] Fig. 1. The dimer unit of two quadratic antiprism Ru–Sn polyhedra. Ru is shown in yellow and Sn red. The displacement ellipsoids in the left picture are shown at the 90% probability level and in the right picture, a polyhedral representation is shown.
[Figure 2] Fig. 2. Perspective view of slightly more than the unit-cell content, with Sn atoms shown as red circles and the two different interpenetrating networks as either yellow or green polyhedra.
(I) top
Crystal data top
Ru3Sn7Mo Kα radiation, λ = 0.71073 Å
Mr = 1134.04Cell parameters from 984 reflections
Cubic, Im3mθ = 1.6–26.0°
a = 9.3532 (19) ŵ = 26.25 mm1
V = 818.2 (3) Å3T = 293 K
Z = 4Prism, dark grey
F(000) = 19280.12 × 0.11 × 0.10 mm
Dx = 9.206 Mg m3
Data collection top
STOE IPDS
diffractometer
102 independent reflections
Radiation source: fine-focus sealed tube97 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.042
Detector resolution: 6.0 pixels mm-1θmax = 25.9°, θmin = 3.1°
area detector scansh = 1111
Absorption correction: numerical
(X-RED; Stoe & Cie, 1997)
k = 119
Tmin = 0.045, Tmax = 0.083l = 117
1394 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.030 w = 1/[σ2(Fo2) + (0.010P)2
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.045(Δ/σ)max < 0.001
S = 2.51Δρmax = 0.83 e Å3
102 reflectionsΔρmin = 2.17 e Å3
10 parametersExtinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
0 restraintsExtinction coefficient: 0.0022 (2)
Crystal data top
Ru3Sn7Z = 4
Mr = 1134.04Mo Kα radiation
Cubic, Im3mµ = 26.25 mm1
a = 9.3532 (19) ÅT = 293 K
V = 818.2 (3) Å30.12 × 0.11 × 0.10 mm
Data collection top
STOE IPDS
diffractometer
102 independent reflections
Absorption correction: numerical
(X-RED; Stoe & Cie, 1997)
97 reflections with I > 2σ(I)
Tmin = 0.045, Tmax = 0.083Rint = 0.042
1394 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.03010 parameters
wR(F2) = 0.0450 restraints
S = 2.51Δρmax = 0.83 e Å3
102 reflectionsΔρmin = 2.17 e Å3
Special details top

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 (Å2) top
xyzUiso*/Ueq
Ru0.34513 (15)0.00000.00000.0067 (4)
Sn10.25000.00000.50000.0094 (4)
Sn20.16110 (6)0.16110 (6)0.16110 (6)0.0086 (4)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Ru0.0058 (7)0.0072 (5)0.0072 (5)0.0000.0000.000
Sn10.0066 (7)0.0108 (5)0.0108 (5)0.0000.0000.000
Sn20.0086 (4)0.0086 (4)0.0086 (4)0.0006 (2)0.0006 (2)0.0006 (2)
Geometric parameters (Å, º) top
Ru—Sn2i2.7393 (11)Sn1—Rux2.7506 (9)
Ru—Sn22.7393 (11)Sn1—Ruxi2.7506 (9)
Ru—Sn2ii2.7393 (11)Sn1—Ruxii2.7506 (9)
Ru—Sn2iii2.7393 (11)Sn2—Rux2.7393 (11)
Ru—Sn1iv2.7506 (9)Sn2—Ruiv2.7393 (11)
Ru—Sn1v2.7506 (9)Sn2—Sn2xiii2.8804 (19)
Ru—Sn1vi2.7506 (9)Sn2—Sn2ii3.0136 (12)
Ru—Sn1vii2.7506 (9)Sn2—Sn2iii3.0136 (12)
Ru—Ruviii2.897 (3)Sn2—Sn2xiv3.0136 (12)
Sn1—Ruix2.7506 (9)
Sn2i—Ru—Sn2102.14 (5)Sn1iv—Ru—Ruviii58.22 (2)
Sn2i—Ru—Sn2ii66.74 (3)Sn1v—Ru—Ruviii58.22 (2)
Sn2—Ru—Sn2ii66.74 (3)Sn1vi—Ru—Ruviii58.22 (2)
Sn2i—Ru—Sn2iii66.74 (3)Sn1vii—Ru—Ruviii58.22 (2)
Sn2—Ru—Sn2iii66.74 (3)Ruix—Sn1—Rux136.27 (3)
Sn2ii—Ru—Sn2iii102.14 (5)Ruix—Sn1—Ruxi63.56 (5)
Sn2i—Ru—Sn1iv142.990 (9)Rux—Sn1—Ruxi136.27 (3)
Sn2—Ru—Sn1iv82.142 (15)Ruix—Sn1—Ruxii136.27 (3)
Sn2ii—Ru—Sn1iv142.990 (9)Rux—Sn1—Ruxii63.56 (5)
Sn2iii—Ru—Sn1iv82.143 (15)Ruxi—Sn1—Ruxii136.27 (3)
Sn2i—Ru—Sn1v142.990 (9)Rux—Sn2—Ruiv112.87 (2)
Sn2—Ru—Sn1v82.142 (15)Rux—Sn2—Ru112.87 (2)
Sn2ii—Ru—Sn1v82.143 (15)Ruiv—Sn2—Ru112.87 (2)
Sn2iii—Ru—Sn1v142.990 (9)Rux—Sn2—Sn2xiii105.81 (2)
Sn1iv—Ru—Sn1v73.90 (2)Ruiv—Sn2—Sn2xiii105.81 (2)
Sn2i—Ru—Sn1vi82.143 (15)Ru—Sn2—Sn2xiii105.81 (2)
Sn2—Ru—Sn1vi142.990 (9)Rux—Sn2—Sn2ii56.628 (13)
Sn2ii—Ru—Sn1vi142.990 (9)Ruiv—Sn2—Sn2ii128.93 (2)
Sn2iii—Ru—Sn1vi82.143 (15)Ru—Sn2—Sn2ii56.628 (13)
Sn1iv—Ru—Sn1vi73.90 (2)Sn2xiii—Sn2—Sn2ii125.3
Sn1v—Ru—Sn1vi116.44 (5)Rux—Sn2—Sn2iii128.93 (2)
Sn2i—Ru—Sn1vii82.143 (15)Ruiv—Sn2—Sn2iii56.628 (13)
Sn2—Ru—Sn1vii142.990 (9)Ru—Sn2—Sn2iii56.628 (13)
Sn2ii—Ru—Sn1vii82.143 (15)Sn2xiii—Sn2—Sn2iii125.3
Sn2iii—Ru—Sn1vii142.990 (9)Sn2ii—Sn2—Sn2iii90.0
Sn1iv—Ru—Sn1vii116.44 (5)Rux—Sn2—Sn2xiv56.628 (13)
Sn1v—Ru—Sn1vii73.90 (2)Ruiv—Sn2—Sn2xiv56.628 (13)
Sn1vi—Ru—Sn1vii73.90 (2)Ru—Sn2—Sn2xiv128.93 (2)
Sn2i—Ru—Ruviii128.93 (2)Sn2xiii—Sn2—Sn2xiv125.3
Sn2—Ru—Ruviii128.93 (2)Sn2ii—Sn2—Sn2xiv90.0
Sn2ii—Ru—Ruviii128.93 (2)Sn2iii—Sn2—Sn2xiv90.0
Sn2iii—Ru—Ruviii128.93 (2)
Symmetry codes: (i) x, y, z; (ii) x, y, z; (iii) x, y, z; (iv) z, x, y; (v) y+1/2, z+1/2, x+1/2; (vi) y+1/2, z1/2, x1/2; (vii) z+1, x, y; (viii) x+1, y, z; (ix) z+1/2, x+1/2, y+1/2; (x) y, z, x; (xi) z+1/2, x1/2, y+1/2; (xii) y, z, x+1; (xiii) x+1/2, y+1/2, z+1/2; (xiv) x, y, z.

Experimental details

Crystal data
Chemical formulaRu3Sn7
Mr1134.04
Crystal system, space groupCubic, Im3m
Temperature (K)293
a (Å)9.3532 (19)
V3)818.2 (3)
Z4
Radiation typeMo Kα
µ (mm1)26.25
Crystal size (mm)0.12 × 0.11 × 0.10
Data collection
DiffractometerSTOE IPDS
diffractometer
Absorption correctionNumerical
(X-RED; Stoe & Cie, 1997)
Tmin, Tmax0.045, 0.083
No. of measured, independent and
observed [I > 2σ(I)] reflections
1394, 102, 97
Rint0.042
(sin θ/λ)max1)0.614
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.030, 0.045, 2.51
No. of reflections102
No. of parameters10
Δρmax, Δρmin (e Å3)0.83, 2.17

Computer programs: EXPOSE in IPDS (Stoe & Cie, 1997), CELL in IPDS, X-RED (Stoe & Cie, 1997), SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), DIAMOND (Bergerhoff, 1996).

Selected bond lengths (Å) top
Ru—Sn22.7393 (11)Sn2—Sn2iii2.8804 (19)
Ru—Sn1i2.7506 (9)Sn2—Sn2iv3.0136 (12)
Ru—Ruii2.897 (3)
Symmetry codes: (i) z, x, y; (ii) x+1, y, z; (iii) x+1/2, y+1/2, z+1/2; (iv) x, y, z.
 

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