Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270113014492/ku3095sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270113014492/ku3095Isup2.hkl | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270113014492/ku3095IIsup3.hkl |
The Tm–Co–Sn samples were prepared by direct arc-melting of the constituent elements (thulium of 99.98 wt% purity, cobalt of 99.99 wt% purity and tin of 99.99 wt% purity) under a high-purity argon atmosphere at 100 kPa. The Tm–Li–Co–Sn alloys (lithium with a nominal purity more than 99.9 wt%) were prepared in Ta crucibles, which were placed in a resistance furnace with a thermocouple controller. The heating rate from room temperature to 670 K was 5 K min-1. The alloy was kept at this temperature for over 2 d [Please be more exact] and then the temperature was increased from 670 to 1170 K over a period of 4 h. The alloy was then annealed at this temperature for 12 h and slowly cooled to room temperature [rate of cooling?]. After melting, the composition of the alloys was controlled by comparing the weights of the initial mixtures and alloys. The total weight loss was less than 2%. Wavelength dispersive spectrometry (WDS) and electron probe microanalysis (EPMA) on a CAMECA SX-100 instrument were used for the determination of the molar proportions between Tm, Co and Sn (Tm8.81Co22.08Sn69.11 for the ternary phase and Tm4.05Li6.16Co22.10Sn67.69 for the quaternary phase in at.%). The lithium content was calculated by difference. After mechanical defragmentation of Tm10Co20Sn70 and Tm5Li5Co20Sn70, small prismatic single crystals of the alloys were isolated for X-ray investigation.
X-ray diffraction on powderized samples was performed by means of a Stoe STADI P diffractometer (Cu Ka radiation, step mode of scanning) in order to confirm the phase analysis and check the purity of the phases. Rietveld matrix full-profile structure refinements confirm well the powder patterns calculated on the basis of single-crystal models (Fig. 6). For the ternary phase: RB = 4.76, Rf = 3.76, Rp = 7.18, Rwp = 9.97 and χ2 = 8.27; for the quaternary phase: RB = 4.94, Rf = 3.87, Rp = 6.09 Rwp = 8.27 and χ2 = 6.82.
Both alloys are practically single-phase. Therefore, to confirm the accuracy of the compositions, the densities of the alloys were determined using the volumetric method. For the ternary phase of Tm7.87Co21.45Sn70.68 the measured density is 8.29 (5) Mg m-3, and that for the quaternary phase of Tm3.68Li6.79Co20.91Sn68.62 is 7.64 (5) Mg m-3. These values differ by less than 2% from the densities calculated from the X-ray data.
Structures (I) and (II) were solved by direct methods.
In phase (I), atoms Tm2, Sn2 and Sn3 partially occupy 32f sites and therefore this structure is positionally disordered. The refinement of the structure model with Sn2–Sn3 split atoms and partially occupied Tm2 leads to a sharp reduction in the value of the conventional R index.
In the first stage of structure solution of quaternary phase (II), the positions of the Tm, Co and Sn atoms were obtained by direct methods. After the refinement of these atoms, the residual factor R1 = 0.035 and the height of the difference peak is 4.43 e Å-3. The remaining Li atoms were located in subsequent difference Fourier syntheses and, after refinement of their parameters, the residual factor decreased to R1 = 0.028 and the height of the difference peak decreased to 1.23 e Å-3. The Li atoms fully occupy an 8c site, with position coordinates x = 3/4, y = 1/4 and z = 1/4, which are very close to the positional coordinates x = 0.7302, y = 0.2698 and z = 0.2698 for the Tm2 atoms in phase (I).
The final refined chemical compositions of the title compounds are very well correlated with the results of electron-probe microanalysis. The mean compositions from electron probe microanalysis are Tm8.81Co22.08Sn69.11 for the ternary phase and Tm4.05Li6.16Co22.10Sn67.69 for the quaternary phase (Li content calculated by difference). The compositions (in at.%) for these phases from X-ray data are Tm7.99Co21.23Sn70.78 and Tm3.45Li6.89Co20.69Sn68.97, respectively.
For both compounds, data collection: CrysAlis CCD (Oxford Diffraction, 2008); cell refinement: CrysAlis CCD (Oxford Diffraction, 2008); data reduction: CrysAlis RED (Oxford Diffraction, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2006); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).
Tm2.22Co6Sn20 | Dx = 8.325 Mg m−3 Dm = 8.29 (5) Mg m−3 Dm measured by volumetric |
Mr = 3102.13 | Mo Kα radiation, λ = 0.71073 Å |
Cubic, Fm3m | Cell parameters from 3055 reflections |
Hall symbol: -F 4 2 3 | θ = 4.3–27.4° |
a = 13.5365 (7) Å | µ = 31.41 mm−1 |
V = 2480.4 (2) Å3 | T = 293 K |
Z = 4 | Prism, metallic dark grey |
F(000) = 5259.6 | 0.08 × 0.05 × 0.04 mm |
Oxford Xcalibur3 CCD area-detector diffractometer | 184 independent reflections |
Radiation source: fine-focus sealed tube | 152 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.082 |
Detector resolution: 0 pixels mm-1 | θmax = 27.4°, θmin = 4.3° |
ω scans | h = −17→15 |
Absorption correction: analytical (CrysAlis RED; Oxford Diffraction, 2008) | k = −17→15 |
Tmin = 0.196, Tmax = 0.312 | l = −15→17 |
3055 measured 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)] = 0.030 | w = 1/[σ2(Fo2) + (0.0579P)2] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.081 | (Δ/σ)max = 0.003 |
S = 1.08 | Δρmax = 1.52 e Å−3 |
184 reflections | Δρmin = −2.19 e Å−3 |
21 parameters | Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
0 restraints | Extinction coefficient: 0.00003 (1) |
Tm2.22Co6Sn20 | Z = 4 |
Mr = 3102.13 | Mo Kα radiation |
Cubic, Fm3m | µ = 31.41 mm−1 |
a = 13.5365 (7) Å | T = 293 K |
V = 2480.4 (2) Å3 | 0.08 × 0.05 × 0.04 mm |
Oxford Xcalibur3 CCD area-detector diffractometer | 184 independent reflections |
Absorption correction: analytical (CrysAlis RED; Oxford Diffraction, 2008) | 152 reflections with I > 2σ(I) |
Tmin = 0.196, Tmax = 0.312 | Rint = 0.082 |
3055 measured reflections |
R[F2 > 2σ(F2)] = 0.030 | 21 parameters |
wR(F2) = 0.081 | 0 restraints |
S = 1.08 | Δρmax = 1.52 e Å−3 |
184 reflections | Δρmin = −2.19 e Å−3 |
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 | Occ. (<1) | |
Tm1 | 0.5000 | 0.5000 | 0.0000 | 0.0165 (5) | |
Tm2 | 0.26969 (18) | 0.73031 (18) | 0.26969 (18) | 0.0195 (17) | 0.152 (2) |
Sn1 | 0.32706 (5) | 0.5000 | 0.17294 (5) | 0.0193 (4) | |
Sn2 | 0.36584 (7) | 0.63416 (7) | 0.36584 (7) | 0.0094 (6) | 0.640 (4) |
Sn3 | 0.41092 (12) | 0.58908 (12) | 0.41092 (12) | 0.0104 (9) | 0.360 (4) |
Co1 | 0.5000 | 0.5000 | 0.25537 (18) | 0.0156 (6) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Tm1 | 0.0165 (5) | 0.0165 (5) | 0.0165 (5) | 0.000 | 0.000 | 0.000 |
Tm2 | 0.0195 (17) | 0.0195 (17) | 0.0195 (17) | 0.0044 (8) | −0.0044 (8) | 0.0044 (8) |
Sn1 | 0.0185 (5) | 0.0208 (6) | 0.0185 (5) | 0.000 | −0.0005 (4) | 0.000 |
Sn2 | 0.0094 (6) | 0.0094 (6) | 0.0094 (6) | −0.0021 (4) | 0.0021 (4) | −0.0021 (4) |
Sn3 | 0.0104 (9) | 0.0104 (9) | 0.0104 (9) | −0.0022 (6) | 0.0022 (6) | −0.0022 (6) |
Co1 | 0.0150 (8) | 0.0150 (8) | 0.0168 (13) | 0.000 | 0.000 | 0.000 |
Tm1—Sn1i | 3.3106 (9) | Sn1—Tm2xvii | 3.4695 (18) |
Tm1—Sn1ii | 3.3106 (9) | Sn1—Tm2xviii | 3.4695 (18) |
Tm1—Sn1iii | 3.3106 (9) | Sn1—Tm2xii | 3.4695 (18) |
Tm1—Sn1iv | 3.3106 (9) | Sn2—Sn3 | 1.057 (3) |
Tm1—Sn1v | 3.3106 (9) | Sn2—Tm2xii | 2.903 (2) |
Tm1—Sn1vi | 3.3106 (9) | Sn2—Tm2xiii | 2.903 (2) |
Tm1—Sn1vii | 3.3106 (9) | Sn2—Tm2xiv | 2.903 (2) |
Tm1—Sn1viii | 3.3106 (9) | Sn2—Co1xix | 2.9720 (14) |
Tm1—Sn1ix | 3.3106 (9) | Sn2—Co1xx | 2.9720 (14) |
Tm1—Sn1x | 3.3106 (9) | Sn2—Co1 | 2.9720 (14) |
Tm1—Sn1 | 3.3106 (9) | Sn2—Sn3xxi | 3.1427 (16) |
Tm1—Sn1xi | 3.3106 (9) | Sn2—Sn3xxii | 3.1427 (16) |
Tm2—Tm2xii | 0.754 (7) | Sn2—Sn3xviii | 3.1427 (16) |
Tm2—Tm2xiii | 0.754 (7) | Sn3—Sn3xviii | 2.412 (3) |
Tm2—Tm2xiv | 0.754 (7) | Sn3—Sn3xxi | 2.412 (3) |
Tm2—Sn2 | 2.254 (5) | Sn3—Sn3xxii | 2.412 (3) |
Tm2—Sn2xii | 2.903 (2) | Sn3—Co1xix | 2.710 (2) |
Tm2—Sn2xiii | 2.903 (2) | Sn3—Co1xx | 2.710 (2) |
Tm2—Sn2xiv | 2.903 (2) | Sn3—Co1 | 2.7096 (19) |
Tm2—Sn3 | 3.311 (5) | Sn3—Sn2xxii | 3.1427 (16) |
Tm2—Sn1xv | 3.4695 (18) | Sn3—Sn2xviii | 3.1427 (16) |
Tm2—Sn1xvi | 3.4695 (18) | Sn3—Sn2xxi | 3.1427 (16) |
Tm2—Sn1 | 3.4695 (18) | Co1—Sn1viii | 2.5933 (11) |
Tm2—Sn1xvii | 3.4695 (18) | Co1—Sn1ii | 2.5933 (11) |
Sn1—Co1 | 2.5933 (11) | Co1—Sn1v | 2.5933 (11) |
Sn1—Co1ix | 2.5933 (11) | Co1—Sn3xxi | 2.7096 (19) |
Sn1—Sn1xvii | 2.9505 (18) | Co1—Sn3v | 2.7096 (19) |
Sn1—Sn2 | 3.2237 (6) | Co1—Sn3xviii | 2.7096 (19) |
Sn1—Sn2xvii | 3.2237 (6) | Co1—Sn2xxi | 2.9720 (14) |
Sn1—Sn2xviii | 3.2237 (6) | Co1—Sn2xviii | 2.9720 (14) |
Sn1—Sn2xii | 3.2237 (6) | Co1—Sn2v | 2.9720 (14) |
Sn1i—Tm1—Sn1ii | 180.000 (16) | Sn2xii—Sn1—Tm2xii | 39.15 (7) |
Sn1i—Tm1—Sn1iii | 60.0 | Tm1—Sn1—Tm2xii | 115.16 (2) |
Sn1ii—Tm1—Sn1iii | 120.0 | Tm2—Sn1—Tm2xii | 12.47 (12) |
Sn1i—Tm1—Sn1iv | 120.0 | Tm2xvii—Sn1—Tm2xii | 127.94 (7) |
Sn1ii—Tm1—Sn1iv | 60.0 | Tm2xviii—Sn1—Tm2xii | 129.67 (4) |
Sn1iii—Tm1—Sn1iv | 180.0 | Sn3—Sn2—Tm2 | 180.0 (2) |
Sn1i—Tm1—Sn1v | 120.0 | Sn3—Sn2—Tm2xii | 171.38 (7) |
Sn1ii—Tm1—Sn1v | 60.0 | Tm2—Sn2—Tm2xii | 8.62 (7) |
Sn1iii—Tm1—Sn1v | 120.0 | Sn3—Sn2—Tm2xiii | 171.38 (7) |
Sn1iv—Tm1—Sn1v | 60.0 | Tm2—Sn2—Tm2xiii | 8.62 (7) |
Sn1i—Tm1—Sn1vi | 90.0 | Tm2xii—Sn2—Tm2xiii | 14.92 (13) |
Sn1ii—Tm1—Sn1vi | 90.0 | Sn3—Sn2—Tm2xiv | 171.38 (7) |
Sn1iii—Tm1—Sn1vi | 120.0 | Tm2—Sn2—Tm2xiv | 8.62 (7) |
Sn1iv—Tm1—Sn1vi | 60.0 | Tm2xii—Sn2—Tm2xiv | 14.92 (13) |
Sn1v—Tm1—Sn1vi | 120.0 | Tm2xiii—Sn2—Tm2xiv | 14.92 (13) |
Sn1i—Tm1—Sn1vii | 60.0 | Sn3—Sn2—Co1xix | 65.47 (5) |
Sn1ii—Tm1—Sn1vii | 120.0 | Tm2—Sn2—Co1xix | 114.53 (5) |
Sn1iii—Tm1—Sn1vii | 60.0 | Tm2xii—Sn2—Co1xix | 123.15 (9) |
Sn1iv—Tm1—Sn1vii | 120.0 | Tm2xiii—Sn2—Co1xix | 110.01 (6) |
Sn1v—Tm1—Sn1vii | 180.0 | Tm2xiv—Sn2—Co1xix | 110.01 (6) |
Sn1vi—Tm1—Sn1vii | 60.0 | Sn3—Sn2—Co1xx | 65.47 (5) |
Sn1i—Tm1—Sn1viii | 90.0 | Tm2—Sn2—Co1xx | 114.53 (5) |
Sn1ii—Tm1—Sn1viii | 90.0 | Tm2xii—Sn2—Co1xx | 110.01 (6) |
Sn1iii—Tm1—Sn1viii | 60.0 | Tm2xiii—Sn2—Co1xx | 123.15 (9) |
Sn1iv—Tm1—Sn1viii | 120.0 | Tm2xiv—Sn2—Co1xx | 110.01 (6) |
Sn1v—Tm1—Sn1viii | 60.0 | Co1xix—Sn2—Co1xx | 103.98 (6) |
Sn1vi—Tm1—Sn1viii | 180.00 (3) | Sn3—Sn2—Co1 | 65.47 (5) |
Sn1vii—Tm1—Sn1viii | 120.0 | Tm2—Sn2—Co1 | 114.53 (5) |
Sn1i—Tm1—Sn1ix | 120.0 | Tm2xii—Sn2—Co1 | 110.01 (6) |
Sn1ii—Tm1—Sn1ix | 60.0 | Tm2xiii—Sn2—Co1 | 110.01 (6) |
Sn1iii—Tm1—Sn1ix | 90.0 | Tm2xiv—Sn2—Co1 | 123.15 (9) |
Sn1iv—Tm1—Sn1ix | 90.0 | Co1xix—Sn2—Co1 | 103.98 (6) |
Sn1v—Tm1—Sn1ix | 120.0 | Co1xx—Sn2—Co1 | 103.98 (6) |
Sn1vi—Tm1—Sn1ix | 60.0 | Sn3—Sn2—Sn3xxi | 38.80 (5) |
Sn1vii—Tm1—Sn1ix | 60.0 | Tm2—Sn2—Sn3xxi | 141.20 (5) |
Sn1viii—Tm1—Sn1ix | 120.0 | Tm2xii—Sn2—Sn3xxi | 144.84 (6) |
Sn1i—Tm1—Sn1x | 60.0 | Tm2xiii—Sn2—Sn3xxi | 132.58 (9) |
Sn1ii—Tm1—Sn1x | 120.0 | Tm2xiv—Sn2—Sn3xxi | 144.84 (6) |
Sn1iii—Tm1—Sn1x | 90.0 | Co1xix—Sn2—Sn3xxi | 52.52 (4) |
Sn1iv—Tm1—Sn1x | 90.0 | Co1xx—Sn2—Sn3xxi | 104.27 (8) |
Sn1v—Tm1—Sn1x | 60.0 | Co1—Sn2—Sn3xxi | 52.52 (4) |
Sn1vi—Tm1—Sn1x | 120.0 | Sn3—Sn2—Sn3xxii | 38.80 (5) |
Sn1vii—Tm1—Sn1x | 120.0 | Tm2—Sn2—Sn3xxii | 141.20 (5) |
Sn1viii—Tm1—Sn1x | 60.0 | Tm2xii—Sn2—Sn3xxii | 144.84 (6) |
Sn1ix—Tm1—Sn1x | 180.0 | Tm2xiii—Sn2—Sn3xxii | 144.84 (6) |
Sn1i—Tm1—Sn1 | 120.0 | Tm2xiv—Sn2—Sn3xxii | 132.58 (9) |
Sn1ii—Tm1—Sn1 | 60.0 | Co1xix—Sn2—Sn3xxii | 52.52 (4) |
Sn1iii—Tm1—Sn1 | 60.0 | Co1xx—Sn2—Sn3xxii | 52.52 (4) |
Sn1iv—Tm1—Sn1 | 120.0 | Co1—Sn2—Sn3xxii | 104.27 (8) |
Sn1v—Tm1—Sn1 | 90.0 | Sn3xxi—Sn2—Sn3xxii | 65.72 (8) |
Sn1vi—Tm1—Sn1 | 120.0 | Sn3—Sn2—Sn3xviii | 38.80 (5) |
Sn1vii—Tm1—Sn1 | 90.0 | Tm2—Sn2—Sn3xviii | 141.20 (5) |
Sn1viii—Tm1—Sn1 | 60.0 | Tm2xii—Sn2—Sn3xviii | 132.58 (9) |
Sn1ix—Tm1—Sn1 | 60.0 | Tm2xiii—Sn2—Sn3xviii | 144.84 (6) |
Sn1x—Tm1—Sn1 | 120.0 | Tm2xiv—Sn2—Sn3xviii | 144.84 (6) |
Sn1i—Tm1—Sn1xi | 60.0 | Co1xix—Sn2—Sn3xviii | 104.27 (8) |
Sn1ii—Tm1—Sn1xi | 120.0 | Co1xx—Sn2—Sn3xviii | 52.52 (4) |
Sn1iii—Tm1—Sn1xi | 120.0 | Co1—Sn2—Sn3xviii | 52.52 (4) |
Sn1iv—Tm1—Sn1xi | 60.0 | Sn3xxi—Sn2—Sn3xviii | 65.72 (8) |
Sn1v—Tm1—Sn1xi | 90.0 | Sn3xxii—Sn2—Sn3xviii | 65.72 (8) |
Sn1vi—Tm1—Sn1xi | 60.0 | Sn3—Sn2—Sn1 | 103.67 (3) |
Sn1vii—Tm1—Sn1xi | 90.0 | Tm2—Sn2—Sn1 | 76.33 (3) |
Sn1viii—Tm1—Sn1xi | 120.0 | Tm2xii—Sn2—Sn1 | 68.76 (7) |
Sn1ix—Tm1—Sn1xi | 120.0 | Tm2xiii—Sn2—Sn1 | 76.77 (3) |
Sn1x—Tm1—Sn1xi | 60.0 | Tm2xiv—Sn2—Sn1 | 83.68 (7) |
Sn1—Tm1—Sn1xi | 180.0 | Co1xix—Sn2—Sn1 | 151.39 (3) |
Tm2xii—Tm2—Tm2xiii | 60.000 (1) | Co1xx—Sn2—Sn1 | 93.945 (17) |
Tm2xii—Tm2—Tm2xiv | 60.000 (1) | Co1—Sn2—Sn1 | 49.28 (3) |
Tm2xiii—Tm2—Tm2xiv | 60.000 (1) | Sn3xxi—Sn2—Sn1 | 101.80 (2) |
Tm2xii—Tm2—Sn2 | 144.736 (1) | Sn3xxii—Sn2—Sn1 | 134.51 (5) |
Tm2xiii—Tm2—Sn2 | 144.736 (1) | Sn3xviii—Sn2—Sn1 | 69.34 (5) |
Tm2xiv—Tm2—Sn2 | 144.736 (1) | Sn2—Sn3—Sn3xviii | 125.264 (1) |
Tm2xii—Tm2—Sn2xii | 26.64 (7) | Sn2—Sn3—Sn3xxi | 125.264 (1) |
Tm2xiii—Tm2—Sn2xii | 82.54 (6) | Sn3xviii—Sn3—Sn3xxi | 90.000 (1) |
Tm2xiv—Tm2—Sn2xii | 82.54 (6) | Sn2—Sn3—Sn3xxii | 125.3 |
Sn2—Tm2—Sn2xii | 118.10 (7) | Sn3xviii—Sn3—Sn3xxii | 90.0 |
Tm2xii—Tm2—Sn2xiii | 82.54 (6) | Sn3xxi—Sn3—Sn3xxii | 90.0 |
Tm2xiii—Tm2—Sn2xiii | 26.64 (7) | Sn2—Sn3—Co1xix | 93.74 (7) |
Tm2xiv—Tm2—Sn2xiii | 82.54 (6) | Sn3xviii—Sn3—Co1xix | 141.00 (7) |
Sn2—Tm2—Sn2xiii | 118.10 (7) | Sn3xxi—Sn3—Co1xix | 63.58 (4) |
Sn2xii—Tm2—Sn2xiii | 99.63 (9) | Sn3xxii—Sn3—Co1xix | 63.58 (4) |
Tm2xii—Tm2—Sn2xiv | 82.54 (6) | Sn2—Sn3—Co1xx | 93.74 (7) |
Tm2xiii—Tm2—Sn2xiv | 82.54 (6) | Sn3xviii—Sn3—Co1xx | 63.58 (4) |
Tm2xiv—Tm2—Sn2xiv | 26.64 (7) | Sn3xxi—Sn3—Co1xx | 141.00 (7) |
Sn2—Tm2—Sn2xiv | 118.10 (7) | Sn3xxii—Sn3—Co1xx | 63.58 (4) |
Sn2xii—Tm2—Sn2xiv | 99.63 (9) | Co1xix—Sn3—Co1xx | 119.579 (15) |
Sn2xiii—Tm2—Sn2xiv | 99.63 (9) | Sn2—Sn3—Co1 | 93.74 (7) |
Tm2xii—Tm2—Sn3 | 144.736 (1) | Sn3xviii—Sn3—Co1 | 63.58 (4) |
Tm2xiii—Tm2—Sn3 | 144.736 (1) | Sn3xxi—Sn3—Co1 | 63.58 (4) |
Tm2xiv—Tm2—Sn3 | 144.736 (1) | Sn3xxii—Sn3—Co1 | 141.00 (7) |
Sn2—Tm2—Sn3 | 0.00 (6) | Co1xix—Sn3—Co1 | 119.579 (15) |
Sn2xii—Tm2—Sn3 | 118.10 (7) | Co1xx—Sn3—Co1 | 119.579 (15) |
Sn2xiii—Tm2—Sn3 | 118.10 (7) | Sn2—Sn3—Sn2xxii | 109.32 (5) |
Sn2xiv—Tm2—Sn3 | 118.10 (7) | Sn3xviii—Sn3—Sn2xxii | 101.20 (4) |
Tm2xii—Tm2—Sn1xv | 142.53 (5) | Sn3xxi—Sn3—Sn2xxii | 101.20 (4) |
Tm2xiii—Tm2—Sn1xv | 83.76 (6) | Sn3xxii—Sn3—Sn2xxii | 15.94 (5) |
Tm2xiv—Tm2—Sn1xv | 111.62 (5) | Co1xix—Sn3—Sn2xxii | 60.502 (19) |
Sn2—Tm2—Sn1xv | 64.53 (6) | Co1xx—Sn3—Sn2xxii | 60.502 (19) |
Sn2xii—Tm2—Sn1xv | 151.481 (15) | Co1—Sn3—Sn2xxii | 156.94 (11) |
Sn2xiii—Tm2—Sn1xv | 59.999 (11) | Sn2—Sn3—Sn2xviii | 109.32 (5) |
Sn2xiv—Tm2—Sn1xv | 103.237 (13) | Sn3xviii—Sn3—Sn2xviii | 15.94 (5) |
Sn3—Tm2—Sn1xv | 64.53 (6) | Sn3xxi—Sn3—Sn2xviii | 101.20 (4) |
Tm2xii—Tm2—Sn1xvi | 142.53 (5) | Sn3xxii—Sn3—Sn2xviii | 101.20 (4) |
Tm2xiii—Tm2—Sn1xvi | 111.62 (5) | Co1xix—Sn3—Sn2xviii | 156.94 (11) |
Tm2xiv—Tm2—Sn1xvi | 83.76 (6) | Co1xx—Sn3—Sn2xviii | 60.502 (19) |
Sn2—Tm2—Sn1xvi | 64.53 (6) | Co1—Sn3—Sn2xviii | 60.502 (19) |
Sn2xii—Tm2—Sn1xvi | 151.481 (15) | Sn2xxii—Sn3—Sn2xviii | 109.62 (5) |
Sn2xiii—Tm2—Sn1xvi | 103.237 (14) | Sn2—Sn3—Sn2xxi | 109.32 (5) |
Sn2xiv—Tm2—Sn1xvi | 59.999 (11) | Sn3xviii—Sn3—Sn2xxi | 101.20 (4) |
Sn3—Tm2—Sn1xvi | 64.53 (6) | Sn3xxi—Sn3—Sn2xxi | 15.94 (5) |
Sn1xv—Tm2—Sn1xvi | 56.99 (4) | Sn3xxii—Sn3—Sn2xxi | 101.20 (4) |
Tm2xii—Tm2—Sn1 | 83.76 (6) | Co1xix—Sn3—Sn2xxi | 60.502 (19) |
Tm2xiii—Tm2—Sn1 | 111.62 (5) | Co1xx—Sn3—Sn2xxi | 156.94 (11) |
Tm2xiv—Tm2—Sn1 | 142.53 (5) | Co1—Sn3—Sn2xxi | 60.502 (19) |
Sn2—Tm2—Sn1 | 64.53 (6) | Sn2xxii—Sn3—Sn2xxi | 109.62 (5) |
Sn2xii—Tm2—Sn1 | 59.999 (11) | Sn2xviii—Sn3—Sn2xxi | 109.62 (5) |
Sn2xiii—Tm2—Sn1 | 103.237 (13) | Sn2—Sn3—Tm2 | 0.00 (16) |
Sn2xiv—Tm2—Sn1 | 151.481 (15) | Sn3xviii—Sn3—Tm2 | 125.3 |
Sn3—Tm2—Sn1 | 64.53 (6) | Sn3xxi—Sn3—Tm2 | 125.3 |
Sn1xv—Tm2—Sn1 | 102.86 (7) | Sn3xxii—Sn3—Tm2 | 125.3 |
Sn1xvi—Tm2—Sn1 | 128.92 (13) | Co1xix—Sn3—Tm2 | 93.74 (7) |
Tm2xii—Tm2—Sn1xvii | 83.76 (6) | Co1xx—Sn3—Tm2 | 93.74 (7) |
Tm2xiii—Tm2—Sn1xvii | 142.53 (5) | Co1—Sn3—Tm2 | 93.74 (7) |
Tm2xiv—Tm2—Sn1xvii | 111.62 (5) | Sn2xxii—Sn3—Tm2 | 109.32 (5) |
Sn2—Tm2—Sn1xvii | 64.53 (6) | Sn2xviii—Sn3—Tm2 | 109.32 (5) |
Sn2xii—Tm2—Sn1xvii | 59.999 (11) | Sn2xxi—Sn3—Tm2 | 109.32 (5) |
Sn2xiii—Tm2—Sn1xvii | 151.481 (15) | Sn1—Co1—Sn1viii | 79.33 (4) |
Sn2xiv—Tm2—Sn1xvii | 103.237 (14) | Sn1—Co1—Sn1ii | 79.33 (4) |
Sn3—Tm2—Sn1xvii | 64.53 (6) | Sn1viii—Co1—Sn1ii | 129.03 (11) |
Sn1xv—Tm2—Sn1xvii | 128.92 (13) | Sn1—Co1—Sn1v | 129.03 (11) |
Sn1xvi—Tm2—Sn1xvii | 102.86 (7) | Sn1viii—Co1—Sn1v | 79.33 (4) |
Sn1—Tm2—Sn1xvii | 50.33 (4) | Sn1ii—Co1—Sn1v | 79.33 (4) |
Co1—Sn1—Co1ix | 140.97 (11) | Sn1—Co1—Sn3xxi | 137.40 (5) |
Co1—Sn1—Sn1xvii | 109.52 (6) | Sn1viii—Co1—Sn3xxi | 137.40 (5) |
Co1ix—Sn1—Sn1xvii | 109.52 (6) | Sn1ii—Co1—Sn3xxi | 86.14 (6) |
Co1—Sn1—Sn2 | 60.30 (4) | Sn1v—Co1—Sn3xxi | 86.14 (6) |
Co1ix—Sn1—Sn2 | 143.25 (3) | Sn1—Co1—Sn3 | 86.14 (6) |
Sn1xvii—Sn1—Sn2 | 62.766 (15) | Sn1viii—Co1—Sn3 | 137.40 (5) |
Co1—Sn1—Sn2xvii | 143.25 (3) | Sn1ii—Co1—Sn3 | 86.14 (5) |
Co1ix—Sn1—Sn2xvii | 60.30 (4) | Sn1v—Co1—Sn3 | 137.40 (5) |
Sn1xvii—Sn1—Sn2xvii | 62.766 (15) | Sn3xxi—Co1—Sn3 | 52.85 (8) |
Sn2—Sn1—Sn2xvii | 125.53 (3) | Sn1—Co1—Sn3v | 137.40 (5) |
Co1—Sn1—Sn2xviii | 60.30 (4) | Sn1viii—Co1—Sn3v | 86.14 (5) |
Co1ix—Sn1—Sn2xviii | 143.25 (3) | Sn1ii—Co1—Sn3v | 137.40 (5) |
Sn1xvii—Sn1—Sn2xviii | 62.766 (15) | Sn1v—Co1—Sn3v | 86.14 (6) |
Sn2—Sn1—Sn2xviii | 68.58 (5) | Sn3xxi—Co1—Sn3v | 52.85 (8) |
Sn2xvii—Sn1—Sn2xviii | 86.93 (5) | Sn3—Co1—Sn3v | 78.00 (14) |
Co1—Sn1—Sn2xii | 143.25 (3) | Sn1—Co1—Sn3xviii | 86.14 (6) |
Co1ix—Sn1—Sn2xii | 60.30 (4) | Sn1viii—Co1—Sn3xviii | 86.14 (6) |
Sn1xvii—Sn1—Sn2xii | 62.766 (15) | Sn1ii—Co1—Sn3xviii | 137.40 (5) |
Sn2—Sn1—Sn2xii | 86.93 (5) | Sn1v—Co1—Sn3xviii | 137.40 (5) |
Sn2xvii—Sn1—Sn2xii | 68.58 (5) | Sn3xxi—Co1—Sn3xviii | 78.00 (14) |
Sn2xviii—Sn1—Sn2xii | 125.53 (3) | Sn3—Co1—Sn3xviii | 52.85 (8) |
Co1—Sn1—Tm1 | 70.48 (6) | Sn3v—Co1—Sn3xviii | 52.85 (8) |
Co1ix—Sn1—Tm1 | 70.48 (6) | Sn1—Co1—Sn2xxi | 140.185 (14) |
Sn1xvii—Sn1—Tm1 | 180.0 | Sn1viii—Co1—Sn2xxi | 140.185 (14) |
Sn2—Sn1—Tm1 | 117.234 (15) | Sn1ii—Co1—Sn2xxi | 70.42 (3) |
Sn2xvii—Sn1—Tm1 | 117.234 (15) | Sn1v—Co1—Sn2xxi | 70.42 (3) |
Sn2xviii—Sn1—Tm1 | 117.234 (15) | Sn3xxi—Co1—Sn2xxi | 20.79 (7) |
Sn2xii—Sn1—Tm1 | 117.234 (15) | Sn3—Co1—Sn2xxi | 66.98 (5) |
Co1—Sn1—Tm2 | 92.27 (6) | Sn3v—Co1—Sn2xxi | 66.98 (5) |
Co1ix—Sn1—Tm2 | 104.15 (7) | Sn3xviii—Co1—Sn2xxi | 98.79 (10) |
Sn1xvii—Sn1—Tm2 | 64.84 (2) | Sn1—Co1—Sn2 | 70.42 (3) |
Sn2—Sn1—Tm2 | 39.15 (7) | Sn1viii—Co1—Sn2 | 140.185 (14) |
Sn2xvii—Sn1—Tm2 | 112.73 (4) | Sn1ii—Co1—Sn2 | 70.42 (3) |
Sn2xviii—Sn1—Tm2 | 103.70 (6) | Sn1v—Co1—Sn2 | 140.185 (14) |
Sn2xii—Sn1—Tm2 | 51.24 (6) | Sn3xxi—Co1—Sn2 | 66.98 (5) |
Tm1—Sn1—Tm2 | 115.16 (2) | Sn3—Co1—Sn2 | 20.79 (7) |
Co1—Sn1—Tm2xvii | 104.15 (7) | Sn3v—Co1—Sn2 | 98.79 (10) |
Co1ix—Sn1—Tm2xvii | 92.27 (6) | Sn3xviii—Co1—Sn2 | 66.98 (5) |
Sn1xvii—Sn1—Tm2xvii | 64.84 (2) | Sn2xxi—Co1—Sn2 | 75.34 (5) |
Sn2—Sn1—Tm2xvii | 112.73 (4) | Sn1—Co1—Sn2xviii | 70.42 (3) |
Sn2xvii—Sn1—Tm2xvii | 39.15 (7) | Sn1viii—Co1—Sn2xviii | 70.42 (3) |
Sn2xviii—Sn1—Tm2xvii | 51.24 (6) | Sn1ii—Co1—Sn2xviii | 140.185 (14) |
Sn2xii—Sn1—Tm2xvii | 103.70 (6) | Sn1v—Co1—Sn2xviii | 140.185 (14) |
Tm1—Sn1—Tm2xvii | 115.16 (2) | Sn3xxi—Co1—Sn2xviii | 98.79 (10) |
Tm2—Sn1—Tm2xvii | 129.67 (4) | Sn3—Co1—Sn2xviii | 66.98 (5) |
Co1—Sn1—Tm2xviii | 92.27 (6) | Sn3v—Co1—Sn2xviii | 66.98 (5) |
Co1ix—Sn1—Tm2xviii | 104.15 (7) | Sn3xviii—Co1—Sn2xviii | 20.79 (7) |
Sn1xvii—Sn1—Tm2xviii | 64.84 (2) | Sn2xxi—Co1—Sn2xviii | 119.58 (10) |
Sn2—Sn1—Tm2xviii | 103.70 (6) | Sn2—Co1—Sn2xviii | 75.34 (5) |
Sn2xvii—Sn1—Tm2xviii | 51.24 (6) | Sn1—Co1—Sn2v | 140.185 (14) |
Sn2xviii—Sn1—Tm2xviii | 39.15 (7) | Sn1viii—Co1—Sn2v | 70.42 (3) |
Sn2xii—Sn1—Tm2xviii | 112.73 (4) | Sn1ii—Co1—Sn2v | 140.185 (14) |
Tm1—Sn1—Tm2xviii | 115.16 (2) | Sn1v—Co1—Sn2v | 70.42 (3) |
Tm2—Sn1—Tm2xviii | 127.94 (7) | Sn3xxi—Co1—Sn2v | 66.98 (5) |
Tm2xvii—Sn1—Tm2xviii | 12.47 (12) | Sn3—Co1—Sn2v | 98.79 (10) |
Co1—Sn1—Tm2xii | 104.15 (7) | Sn3v—Co1—Sn2v | 20.79 (7) |
Co1ix—Sn1—Tm2xii | 92.27 (6) | Sn3xviii—Co1—Sn2v | 66.98 (5) |
Sn1xvii—Sn1—Tm2xii | 64.84 (2) | Sn2xxi—Co1—Sn2v | 75.34 (5) |
Sn2—Sn1—Tm2xii | 51.24 (6) | Sn2—Co1—Sn2v | 119.58 (10) |
Sn2xvii—Sn1—Tm2xii | 103.70 (6) | Sn2xviii—Co1—Sn2v | 75.34 (5) |
Sn2xviii—Sn1—Tm2xii | 112.73 (4) |
Symmetry codes: (i) y, −z+1/2, x−1/2; (ii) −y+1, z+1/2, −x+1/2; (iii) −z+1/2, x, y−1/2; (iv) z+1/2, −x+1, −y+1/2; (v) −x+1, −y+1, z; (vi) y, z+1/2, x−1/2; (vii) x, y, −z; (viii) −y+1, −z+1/2, −x+1/2; (ix) −z+1/2, −x+1, −y+1/2; (x) z+1/2, x, y−1/2; (xi) −x+1, −y+1, −z; (xii) −x+1/2, y, −z+1/2; (xiii) x, −y+3/2, −z+1/2; (xiv) −x+1/2, −y+3/2, z; (xv) y, −z+1, x; (xvi) −z+1/2, x+1/2, y; (xvii) −x+1/2, −y+1, −z+1/2; (xviii) x, −y+1, z; (xix) −y+1, −z+1, −x+1; (xx) z, x, y; (xxi) −x+1, y, z; (xxii) x, y, −z+1. |
TmLi2Co6Sn20 | Dx = 7.793 Mg m−3 Dm = 7.64 (5) Mg m−3 Dm measured by volumetric |
Mr = 2910.59 | Mo Kα radiation, λ = 0.71073 Å |
Cubic, Fm3m | Cell parameters from 4784 reflections |
Hall symbol: -F 4 2 3 | θ = 4.3–27.4° |
a = 13.5371 (16) Å | µ = 27.12 mm−1 |
V = 2480.7 (9) Å3 | T = 293 K |
Z = 4 | Prism, metallic dark grey |
F(000) = 4948 | 0.09 × 0.06 × 0.05 mm |
Oxford Xcalibur3 CCD area-detector diffractometer | 184 independent reflections |
Radiation source: fine-focus sealed tube | 154 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.034 |
Detector resolution: 0 pixels mm-1 | θmax = 27.4°, θmin = 4.3° |
ω scans | h = −17→17 |
Absorption correction: analytical (CrysAlis RED; Oxford Diffraction, 2008) | k = −17→17 |
Tmin = 0.160, Tmax = 0.265 | l = −17→17 |
4784 measured 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)] = 0.028 | w = 1/[σ2(Fo2) + (0.0428P)2] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.060 | (Δ/σ)max < 0.001 |
S = 1.00 | Δρmax = 1.23 e Å−3 |
184 reflections | Δρmin = −1.47 e Å−3 |
18 parameters | Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
0 restraints | Extinction coefficient: 0.000128 (18) |
TmLi2Co6Sn20 | Z = 4 |
Mr = 2910.59 | Mo Kα radiation |
Cubic, Fm3m | µ = 27.12 mm−1 |
a = 13.5371 (16) Å | T = 293 K |
V = 2480.7 (9) Å3 | 0.09 × 0.06 × 0.05 mm |
Oxford Xcalibur3 CCD area-detector diffractometer | 184 independent reflections |
Absorption correction: analytical (CrysAlis RED; Oxford Diffraction, 2008) | 154 reflections with I > 2σ(I) |
Tmin = 0.160, Tmax = 0.265 | Rint = 0.034 |
4784 measured reflections |
R[F2 > 2σ(F2)] = 0.028 | 18 parameters |
wR(F2) = 0.060 | 0 restraints |
S = 1.00 | Δρmax = 1.23 e Å−3 |
184 reflections | Δρmin = −1.47 e Å−3 |
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 | Occ. (<1) | |
Tm1 | 0.5000 | 0.5000 | 0.0000 | 0.0295 (5) | |
Sn1 | 0.32715 (4) | 0.5000 | 0.17285 (4) | 0.0281 (3) | |
Sn2 | 0.36560 (5) | 0.63440 (5) | 0.36560 (5) | 0.0162 (4) | 0.670 (3) |
Sn3 | 0.41054 (13) | 0.58946 (13) | 0.41054 (13) | 0.0277 (10) | 0.330 (3) |
Co1 | 0.5000 | 0.5000 | 0.25461 (15) | 0.0197 (5) | |
Li1 | 0.2500 | 0.7500 | 0.2500 | 0.040 (12) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Tm1 | 0.0295 (5) | 0.0295 (5) | 0.0295 (5) | 0.000 | 0.000 | 0.000 |
Sn1 | 0.0216 (3) | 0.0410 (5) | 0.0216 (3) | 0.000 | −0.0021 (3) | 0.000 |
Sn2 | 0.0162 (4) | 0.0162 (4) | 0.0162 (4) | −0.0022 (3) | 0.0022 (3) | −0.0022 (3) |
Sn3 | 0.0277 (10) | 0.0277 (10) | 0.0277 (10) | −0.0021 (8) | 0.0021 (8) | −0.0021 (8) |
Co1 | 0.0201 (6) | 0.0201 (6) | 0.0189 (10) | 0.000 | 0.000 | 0.000 |
Li1 | 0.040 (12) | 0.040 (12) | 0.040 (12) | 0.000 | 0.000 | 0.000 |
Tm1—Sn1i | 3.3092 (8) | Sn2—Sn3xiii | 3.1501 (16) |
Tm1—Sn1ii | 3.3092 (8) | Sn2—Sn1xii | 3.2233 (6) |
Tm1—Sn1iii | 3.3092 (8) | Sn2—Sn1xix | 3.2233 (6) |
Tm1—Sn1iv | 3.3092 (8) | Sn2—Sn1xx | 3.2233 (6) |
Tm1—Sn1v | 3.3092 (8) | Sn3—Sn3xvii | 2.422 (4) |
Tm1—Sn1vi | 3.3092 (8) | Sn3—Sn3xiii | 2.422 (3) |
Tm1—Sn1 | 3.3092 (8) | Sn3—Sn3xviii | 2.422 (3) |
Tm1—Sn1vii | 3.3092 (8) | Sn3—Co1xv | 2.7183 (16) |
Tm1—Sn1viii | 3.3092 (8) | Sn3—Co1 | 2.7183 (16) |
Tm1—Sn1ix | 3.3092 (8) | Sn3—Co1xvi | 2.7183 (16) |
Tm1—Sn1x | 3.3092 (8) | Sn3—Sn2xvii | 3.1501 (16) |
Tm1—Sn1xi | 3.3092 (8) | Sn3—Sn2xiii | 3.1501 (16) |
Sn1—Co1vii | 2.5884 (9) | Sn3—Sn2xviii | 3.1501 (16) |
Sn1—Co1 | 2.5884 (9) | Co1—Sn1xi | 2.5884 (9) |
Sn1—Sn1xii | 2.9539 (15) | Co1—Sn1ii | 2.5884 (9) |
Sn1—Sn2 | 3.2233 (6) | Co1—Sn1v | 2.5884 (9) |
Sn1—Sn2xii | 3.2233 (6) | Co1—Sn3xvii | 2.7183 (16) |
Sn1—Sn2xiii | 3.2233 (6) | Co1—Sn3v | 2.7183 (16) |
Sn1—Sn2xiv | 3.2233 (6) | Co1—Sn3xiii | 2.7183 (16) |
Sn2—Sn3 | 1.054 (3) | Co1—Sn2xvii | 2.9795 (12) |
Sn2—Li1 | 2.7106 (13) | Co1—Sn2xiii | 2.9795 (12) |
Sn2—Co1xv | 2.9795 (12) | Co1—Sn2v | 2.9795 (12) |
Sn2—Co1 | 2.9795 (12) | Li1—Sn2xiv | 2.7106 (13) |
Sn2—Co1xvi | 2.9795 (12) | Li1—Sn2xxi | 2.7106 (13) |
Sn2—Sn3xvii | 3.1501 (16) | Li1—Sn2xxii | 2.7106 (13) |
Sn2—Sn3xviii | 3.1501 (16) | ||
Sn1i—Tm1—Sn1ii | 180.00 (3) | Sn3—Sn2—Sn1xix | 103.58 (2) |
Sn1i—Tm1—Sn1iii | 60.0 | Li1—Sn2—Sn1xix | 76.42 (2) |
Sn1ii—Tm1—Sn1iii | 120.0 | Co1xv—Sn2—Sn1xix | 49.14 (3) |
Sn1i—Tm1—Sn1iv | 120.0 | Co1—Sn2—Sn1xix | 93.911 (13) |
Sn1ii—Tm1—Sn1iv | 60.0 | Co1xvi—Sn2—Sn1xix | 151.35 (2) |
Sn1iii—Tm1—Sn1iv | 180.000 (13) | Sn3xvii—Sn2—Sn1xix | 69.18 (5) |
Sn1i—Tm1—Sn1v | 120.0 | Sn3xviii—Sn2—Sn1xix | 101.695 (19) |
Sn1ii—Tm1—Sn1v | 60.0 | Sn3xiii—Sn2—Sn1xix | 134.50 (4) |
Sn1iii—Tm1—Sn1v | 120.0 | Sn1—Sn2—Sn1xix | 114.667 (16) |
Sn1iv—Tm1—Sn1v | 60.0 | Sn1xii—Sn2—Sn1xix | 152.59 (4) |
Sn1i—Tm1—Sn1vi | 60.0 | Sn3—Sn2—Sn1xx | 103.58 (2) |
Sn1ii—Tm1—Sn1vi | 120.0 | Li1—Sn2—Sn1xx | 76.42 (2) |
Sn1iii—Tm1—Sn1vi | 60.0 | Co1xv—Sn2—Sn1xx | 49.14 (3) |
Sn1iv—Tm1—Sn1vi | 120.0 | Co1—Sn2—Sn1xx | 151.35 (2) |
Sn1v—Tm1—Sn1vi | 180.0 | Co1xvi—Sn2—Sn1xx | 93.911 (13) |
Sn1i—Tm1—Sn1 | 120.0 | Sn3xvii—Sn2—Sn1xx | 101.695 (19) |
Sn1ii—Tm1—Sn1 | 60.0 | Sn3xviii—Sn2—Sn1xx | 69.18 (5) |
Sn1iii—Tm1—Sn1 | 60.0 | Sn3xiii—Sn2—Sn1xx | 134.50 (4) |
Sn1iv—Tm1—Sn1 | 120.0 | Sn1—Sn2—Sn1xx | 152.59 (4) |
Sn1v—Tm1—Sn1 | 90.0 | Sn1xii—Sn2—Sn1xx | 114.667 (17) |
Sn1vi—Tm1—Sn1 | 90.0 | Sn1xix—Sn2—Sn1xx | 61.77 (2) |
Sn1i—Tm1—Sn1vii | 120.0 | Sn2—Sn3—Sn3xvii | 125.264 (1) |
Sn1ii—Tm1—Sn1vii | 60.0 | Sn2—Sn3—Sn3xiii | 125.264 (1) |
Sn1iii—Tm1—Sn1vii | 90.0 | Sn3xvii—Sn3—Sn3xiii | 90.0 |
Sn1iv—Tm1—Sn1vii | 90.0 | Sn2—Sn3—Sn3xviii | 125.264 (1) |
Sn1v—Tm1—Sn1vii | 120.0 | Sn3xvii—Sn3—Sn3xviii | 90.0 |
Sn1vi—Tm1—Sn1vii | 60.0 | Sn3xiii—Sn3—Sn3xviii | 90.0 |
Sn1—Tm1—Sn1vii | 60.0 | Sn2—Sn3—Co1xv | 93.79 (7) |
Sn1i—Tm1—Sn1viii | 60.0 | Sn3xvii—Sn3—Co1xv | 63.54 (4) |
Sn1ii—Tm1—Sn1viii | 120.0 | Sn3xiii—Sn3—Co1xv | 140.94 (7) |
Sn1iii—Tm1—Sn1viii | 90.0 | Sn3xviii—Sn3—Co1xv | 63.54 (4) |
Sn1iv—Tm1—Sn1viii | 90.0 | Sn2—Sn3—Co1 | 93.79 (7) |
Sn1v—Tm1—Sn1viii | 60.0 | Sn3xvii—Sn3—Co1 | 63.54 (4) |
Sn1vi—Tm1—Sn1viii | 120.0 | Sn3xiii—Sn3—Co1 | 63.54 (4) |
Sn1—Tm1—Sn1viii | 120.0 | Sn3xviii—Sn3—Co1 | 140.94 (7) |
Sn1vii—Tm1—Sn1viii | 180.0 | Co1xv—Sn3—Co1 | 119.567 (15) |
Sn1i—Tm1—Sn1ix | 60.0 | Sn2—Sn3—Co1xvi | 93.79 (7) |
Sn1ii—Tm1—Sn1ix | 120.0 | Sn3xvii—Sn3—Co1xvi | 140.94 (7) |
Sn1iii—Tm1—Sn1ix | 120.0 | Sn3xiii—Sn3—Co1xvi | 63.54 (4) |
Sn1iv—Tm1—Sn1ix | 60.0 | Sn3xviii—Sn3—Co1xvi | 63.54 (4) |
Sn1v—Tm1—Sn1ix | 90.0 | Co1xv—Sn3—Co1xvi | 119.567 (15) |
Sn1vi—Tm1—Sn1ix | 90.0 | Co1—Sn3—Co1xvi | 119.567 (15) |
Sn1—Tm1—Sn1ix | 180.0 | Sn2—Sn3—Sn2xvii | 109.42 (5) |
Sn1vii—Tm1—Sn1ix | 120.0 | Sn3xvii—Sn3—Sn2xvii | 15.85 (5) |
Sn1viii—Tm1—Sn1ix | 60.0 | Sn3xiii—Sn3—Sn2xvii | 101.13 (4) |
Sn1i—Tm1—Sn1x | 90.0 | Sn3xviii—Sn3—Sn2xvii | 101.13 (4) |
Sn1ii—Tm1—Sn1x | 90.0 | Co1xv—Sn3—Sn2xvii | 60.494 (18) |
Sn1iii—Tm1—Sn1x | 120.0 | Co1—Sn3—Sn2xvii | 60.494 (18) |
Sn1iv—Tm1—Sn1x | 60.0 | Co1xvi—Sn3—Sn2xvii | 156.79 (12) |
Sn1v—Tm1—Sn1x | 120.0 | Sn2—Sn3—Sn2xiii | 109.42 (5) |
Sn1vi—Tm1—Sn1x | 60.0 | Sn3xvii—Sn3—Sn2xiii | 101.13 (4) |
Sn1—Tm1—Sn1x | 120.0 | Sn3xiii—Sn3—Sn2xiii | 15.85 (5) |
Sn1vii—Tm1—Sn1x | 60.0 | Sn3xviii—Sn3—Sn2xiii | 101.13 (4) |
Sn1viii—Tm1—Sn1x | 120.0 | Co1xv—Sn3—Sn2xiii | 156.79 (12) |
Sn1ix—Tm1—Sn1x | 60.0 | Co1—Sn3—Sn2xiii | 60.494 (18) |
Sn1i—Tm1—Sn1xi | 90.0 | Co1xvi—Sn3—Sn2xiii | 60.494 (18) |
Sn1ii—Tm1—Sn1xi | 90.0 | Sn2xvii—Sn3—Sn2xiii | 109.52 (5) |
Sn1iii—Tm1—Sn1xi | 60.0 | Sn2—Sn3—Sn2xviii | 109.42 (5) |
Sn1iv—Tm1—Sn1xi | 120.0 | Sn3xvii—Sn3—Sn2xviii | 101.13 (4) |
Sn1v—Tm1—Sn1xi | 60.0 | Sn3xiii—Sn3—Sn2xviii | 101.13 (4) |
Sn1vi—Tm1—Sn1xi | 120.0 | Sn3xviii—Sn3—Sn2xviii | 15.85 (5) |
Sn1—Tm1—Sn1xi | 60.0 | Co1xv—Sn3—Sn2xviii | 60.494 (18) |
Sn1vii—Tm1—Sn1xi | 120.0 | Co1—Sn3—Sn2xviii | 156.79 (12) |
Sn1viii—Tm1—Sn1xi | 60.0 | Co1xvi—Sn3—Sn2xviii | 60.494 (18) |
Sn1ix—Tm1—Sn1xi | 120.0 | Sn2xvii—Sn3—Sn2xviii | 109.52 (5) |
Sn1x—Tm1—Sn1xi | 180.00 (3) | Sn2xiii—Sn3—Sn2xviii | 109.52 (5) |
Co1vii—Sn1—Co1 | 140.63 (8) | Sn1xi—Co1—Sn1 | 79.47 (3) |
Co1vii—Sn1—Sn1xii | 109.69 (4) | Sn1xi—Co1—Sn1ii | 129.37 (8) |
Co1—Sn1—Sn1xii | 109.69 (4) | Sn1—Co1—Sn1ii | 79.47 (3) |
Co1vii—Sn1—Sn2 | 143.21 (3) | Sn1xi—Co1—Sn1v | 79.47 (3) |
Co1—Sn1—Sn2 | 60.52 (3) | Sn1—Co1—Sn1v | 129.37 (8) |
Sn1xii—Sn1—Sn2 | 62.728 (12) | Sn1ii—Co1—Sn1v | 79.47 (3) |
Co1vii—Sn1—Sn2xii | 60.52 (3) | Sn1xi—Co1—Sn3xvii | 137.29 (4) |
Co1—Sn1—Sn2xii | 143.21 (3) | Sn1—Co1—Sn3xvii | 137.29 (4) |
Sn1xii—Sn1—Sn2xii | 62.728 (12) | Sn1ii—Co1—Sn3xvii | 85.94 (5) |
Sn2—Sn1—Sn2xii | 125.46 (2) | Sn1v—Co1—Sn3xvii | 85.94 (5) |
Co1vii—Sn1—Sn2xiii | 143.21 (3) | Sn1xi—Co1—Sn3v | 85.94 (5) |
Co1—Sn1—Sn2xiii | 60.52 (3) | Sn1—Co1—Sn3v | 137.29 (4) |
Sn1xii—Sn1—Sn2xiii | 62.728 (12) | Sn1ii—Co1—Sn3v | 137.29 (4) |
Sn2—Sn1—Sn2xiii | 68.73 (4) | Sn1v—Co1—Sn3v | 85.94 (5) |
Sn2xii—Sn1—Sn2xiii | 86.73 (4) | Sn3xvii—Co1—Sn3v | 52.92 (8) |
Co1vii—Sn1—Sn2xiv | 60.52 (3) | Sn1xi—Co1—Sn3 | 137.29 (4) |
Co1—Sn1—Sn2xiv | 143.21 (3) | Sn1—Co1—Sn3 | 85.94 (5) |
Sn1xii—Sn1—Sn2xiv | 62.728 (12) | Sn1ii—Co1—Sn3 | 85.94 (5) |
Sn2—Sn1—Sn2xiv | 86.73 (4) | Sn1v—Co1—Sn3 | 137.29 (4) |
Sn2xii—Sn1—Sn2xiv | 68.73 (4) | Sn3xvii—Co1—Sn3 | 52.92 (8) |
Sn2xiii—Sn1—Sn2xiv | 125.46 (2) | Sn3v—Co1—Sn3 | 78.11 (14) |
Co1vii—Sn1—Tm1 | 70.31 (4) | Sn1xi—Co1—Sn3xiii | 85.94 (5) |
Co1—Sn1—Tm1 | 70.31 (4) | Sn1—Co1—Sn3xiii | 85.94 (5) |
Sn1xii—Sn1—Tm1 | 180.0 | Sn1ii—Co1—Sn3xiii | 137.29 (4) |
Sn2—Sn1—Tm1 | 117.272 (12) | Sn1v—Co1—Sn3xiii | 137.29 (4) |
Sn2xii—Sn1—Tm1 | 117.272 (12) | Sn3xvii—Co1—Sn3xiii | 78.11 (14) |
Sn2xiii—Sn1—Tm1 | 117.272 (12) | Sn3v—Co1—Sn3xiii | 52.91 (8) |
Sn2xiv—Sn1—Tm1 | 117.272 (12) | Sn3—Co1—Sn3xiii | 52.92 (8) |
Sn3—Sn2—Li1 | 180.00 (14) | Sn1xi—Co1—Sn2xvii | 140.139 (11) |
Sn3—Sn2—Co1xv | 65.55 (4) | Sn1—Co1—Sn2xvii | 140.139 (11) |
Li1—Sn2—Co1xv | 114.45 (4) | Sn1ii—Co1—Sn2xvii | 70.34 (2) |
Sn3—Sn2—Co1 | 65.55 (4) | Sn1v—Co1—Sn2xvii | 70.34 (2) |
Li1—Sn2—Co1 | 114.45 (4) | Sn3xvii—Co1—Sn2xvii | 20.66 (6) |
Co1xv—Sn2—Co1 | 104.06 (5) | Sn3v—Co1—Sn2xvii | 66.95 (4) |
Sn3—Sn2—Co1xvi | 65.55 (4) | Sn3—Co1—Sn2xvii | 66.95 (4) |
Li1—Sn2—Co1xvi | 114.45 (4) | Sn3xiii—Co1—Sn2xvii | 98.77 (9) |
Co1xv—Sn2—Co1xvi | 104.06 (5) | Sn1xi—Co1—Sn2 | 140.139 (11) |
Co1—Sn2—Co1xvi | 104.06 (5) | Sn1—Co1—Sn2 | 70.34 (2) |
Sn3—Sn2—Sn3xvii | 38.89 (5) | Sn1ii—Co1—Sn2 | 70.34 (2) |
Li1—Sn2—Sn3xvii | 141.11 (5) | Sn1v—Co1—Sn2 | 140.139 (11) |
Co1xv—Sn2—Sn3xvii | 52.56 (3) | Sn3xvii—Co1—Sn2 | 66.95 (4) |
Co1—Sn2—Sn3xvii | 52.56 (3) | Sn3v—Co1—Sn2 | 98.77 (9) |
Co1xvi—Sn2—Sn3xvii | 104.44 (7) | Sn3—Co1—Sn2 | 20.66 (6) |
Sn3—Sn2—Sn3xviii | 38.89 (5) | Sn3xiii—Co1—Sn2 | 66.95 (4) |
Li1—Sn2—Sn3xviii | 141.11 (5) | Sn2xvii—Co1—Sn2 | 75.27 (4) |
Co1xv—Sn2—Sn3xviii | 52.56 (3) | Sn1xi—Co1—Sn2xiii | 70.34 (2) |
Co1—Sn2—Sn3xviii | 104.44 (7) | Sn1—Co1—Sn2xiii | 70.34 (2) |
Co1xvi—Sn2—Sn3xviii | 52.56 (3) | Sn1ii—Co1—Sn2xiii | 140.139 (11) |
Sn3xvii—Sn2—Sn3xviii | 65.87 (8) | Sn1v—Co1—Sn2xiii | 140.139 (11) |
Sn3—Sn2—Sn3xiii | 38.89 (5) | Sn3xvii—Co1—Sn2xiii | 98.77 (9) |
Li1—Sn2—Sn3xiii | 141.11 (5) | Sn3v—Co1—Sn2xiii | 66.95 (4) |
Co1xv—Sn2—Sn3xiii | 104.44 (7) | Sn3—Co1—Sn2xiii | 66.95 (4) |
Co1—Sn2—Sn3xiii | 52.56 (3) | Sn3xiii—Co1—Sn2xiii | 20.66 (6) |
Co1xvi—Sn2—Sn3xiii | 52.56 (3) | Sn2xvii—Co1—Sn2xiii | 119.43 (8) |
Sn3xvii—Sn2—Sn3xiii | 65.87 (8) | Sn2—Co1—Sn2xiii | 75.27 (4) |
Sn3xviii—Sn2—Sn3xiii | 65.87 (8) | Sn1xi—Co1—Sn2v | 70.34 (2) |
Sn3—Sn2—Sn1 | 103.58 (2) | Sn1—Co1—Sn2v | 140.139 (11) |
Li1—Sn2—Sn1 | 76.42 (2) | Sn1ii—Co1—Sn2v | 140.139 (11) |
Co1xv—Sn2—Sn1 | 151.35 (2) | Sn1v—Co1—Sn2v | 70.34 (2) |
Co1—Sn2—Sn1 | 49.14 (3) | Sn3xvii—Co1—Sn2v | 66.95 (4) |
Co1xvi—Sn2—Sn1 | 93.911 (13) | Sn3v—Co1—Sn2v | 20.66 (6) |
Sn3xvii—Sn2—Sn1 | 101.695 (19) | Sn3—Co1—Sn2v | 98.77 (9) |
Sn3xviii—Sn2—Sn1 | 134.50 (4) | Sn3xiii—Co1—Sn2v | 66.95 (4) |
Sn3xiii—Sn2—Sn1 | 69.18 (5) | Sn2xvii—Co1—Sn2v | 75.27 (4) |
Sn3—Sn2—Sn1xii | 103.58 (2) | Sn2—Co1—Sn2v | 119.43 (8) |
Li1—Sn2—Sn1xii | 76.42 (2) | Sn2xiii—Co1—Sn2v | 75.27 (4) |
Co1xv—Sn2—Sn1xii | 151.35 (2) | Sn2xiv—Li1—Sn2xxi | 109.5 |
Co1—Sn2—Sn1xii | 93.911 (13) | Sn2xiv—Li1—Sn2xxii | 109.5 |
Co1xvi—Sn2—Sn1xii | 49.14 (3) | Sn2xxi—Li1—Sn2xxii | 109.5 |
Sn3xvii—Sn2—Sn1xii | 134.50 (4) | Sn2xiv—Li1—Sn2 | 109.5 |
Sn3xviii—Sn2—Sn1xii | 101.695 (19) | Sn2xxi—Li1—Sn2 | 109.5 |
Sn3xiii—Sn2—Sn1xii | 69.18 (5) | Sn2xxii—Li1—Sn2 | 109.5 |
Sn1—Sn2—Sn1xii | 54.54 (2) |
Symmetry codes: (i) y, −z+1/2, x−1/2; (ii) −y+1, z+1/2, −x+1/2; (iii) −z+1/2, x, y−1/2; (iv) z+1/2, −x+1, −y+1/2; (v) −x+1, −y+1, z; (vi) x, y, −z; (vii) −z+1/2, −x+1, −y+1/2; (viii) z+1/2, x, y−1/2; (ix) −x+1, −y+1, −z; (x) y, z+1/2, x−1/2; (xi) −y+1, −z+1/2, −x+1/2; (xii) −x+1/2, −y+1, −z+1/2; (xiii) x, −y+1, z; (xiv) −x+1/2, y, −z+1/2; (xv) −y+1, −z+1, −x+1; (xvi) z, x, y; (xvii) −x+1, y, z; (xviii) x, y, −z+1; (xix) y, −z+1, x; (xx) −z+1/2, x+1/2, y; (xxi) x, −y+3/2, −z+1/2; (xxii) −x+1/2, −y+3/2, z. |
Experimental details
(I) | (II) | |
Crystal data | ||
Chemical formula | Tm2.22Co6Sn20 | TmLi2Co6Sn20 |
Mr | 3102.13 | 2910.59 |
Crystal system, space group | Cubic, Fm3m | Cubic, Fm3m |
Temperature (K) | 293 | 293 |
a (Å) | 13.5365 (7) | 13.5371 (16) |
V (Å3) | 2480.4 (2) | 2480.7 (9) |
Z | 4 | 4 |
Radiation type | Mo Kα | Mo Kα |
µ (mm−1) | 31.41 | 27.12 |
Crystal size (mm) | 0.08 × 0.05 × 0.04 | 0.09 × 0.06 × 0.05 |
Data collection | ||
Diffractometer | Oxford Xcalibur3 CCD area-detector diffractometer | Oxford Xcalibur3 CCD area-detector diffractometer |
Absorption correction | Analytical (CrysAlis RED; Oxford Diffraction, 2008) | Analytical (CrysAlis RED; Oxford Diffraction, 2008) |
Tmin, Tmax | 0.196, 0.312 | 0.160, 0.265 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 3055, 184, 152 | 4784, 184, 154 |
Rint | 0.082 | 0.034 |
(sin θ/λ)max (Å−1) | 0.648 | 0.648 |
Refinement | ||
R[F2 > 2σ(F2)], wR(F2), S | 0.030, 0.081, 1.08 | 0.028, 0.060, 1.00 |
No. of reflections | 184 | 184 |
No. of parameters | 21 | 18 |
Δρmax, Δρmin (e Å−3) | 1.52, −2.19 | 1.23, −1.47 |
Computer programs: CrysAlis CCD (Oxford Diffraction, 2008), CrysAlis RED (Oxford Diffraction, 2008), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg, 2006).
Intermetallic compounds, based on rare earth (RE) elements, transition (T) metals (especially Mn, Fe, Co and Ni) and tin, attract much attention from researchers because they have unique magnetic and transport properties (Canepa et al., 2001; Israel et al., 2005; Mudryk et al., 2001; Skolozdra, 1997; Romaka et al., 2010, 2011). Ternary and quaternary stannides from the RE–Li–Sn and RE–Li–T–Sn systems (Pavlyuk, Bodak et al., 1989 or Pavlyuk, Pecharskii et al., 1989 ?; Stetskiv et al., 2011; Stetskiv, Tarasiuk et al., 2012) can be used as electrode materials for lithium batteries. The Tm–Co–Sn ternary system has not yet been completely studied and only a few ternary phases of this system are known, viz. TmCo0.19Sn2 (Francois et al., 1990), TmCoSn (Dwight et al., 1986) and Tm3Co8Sn4 (Canepa et al., 2000). During our investigation of tin-rich alloys of the ternary Tm–Co–Sn and quaternary Tm–Li–Co–Sn systems, we discovered the two new title phases, ternary Tm2.22Co6Sn20, (I), and quaternary TmLi2Co6Sn20, (II). The single-crystal X-ray diffraction data for these compounds are presented in this work.
Both (I) and (II) crystallize in the same cubic crystal system in the space group Fm3m, with lattice parameters a = 13.5365 (7) Å for (I) and 13.5371 (16) Å for (II). In both structures, the Co atoms are located on 24e sites. One of the 48h sites is fully occupied by Sn atoms (Sn1), and two 32f split positions are occupied by the Sn2–Sn3 atoms in both (I) and (II). Atoms Tm1 in both structures occupy the same 4a site. Atoms Tm2 in phase (I) partially occupy the 32f site, with coordinates x = 0.7302, y = 0.2698 and z = 0.2698, which are very close to the coordinates x = 3/4, y = 1/4 and z = 1/4 (8c site) occupied by the Li atoms in phase (II). The ability of the Li atoms to occupy crystallographic positions which are characteristic of the atoms of RE metals, or to substitute for them, was observed [Added text OK?] in the structures we found earlier for Sm5Ge4–Tm4LiGe4 (Pavlyuk et al., 1990), Sm9Ga4–Yb5Li4Ge4 (Pavlyuk, Bodak et al., 1989 or Pavlyuk, Pecharskii et al., 1989 ?), Tm2Ni12P7–Li2Ni12P7 (Pavlyuk & Bodak, 1992) and LaCoAl4–Li2-xAg1+xIn3 (Chumak et al., 2012). Obviously, substitution of RE atoms by Li occurs because of the relatively small atomic size difference, so geometric factors dominate.
The structures of both (I) and (II) are strongly disordered, due to the presence of mutually excluding atoms and split positions. Therefore, in the average structures, two subcells (A and B) can be selected, and the fraction ratio of subcells A to subcells B is 1:2 (Fig. 1). For the ternary phase, (I), subcell B contains atoms Tm1, Co1, Sn1 and Sn2, but for [no?] Sn3 atoms. Subcell A of (I) contains atoms Tm1, Tm2, Co1, Sn1 and Sn3, but for [no?] Sn2 atoms, and can be interpreted as two structural variants because the Sn3—Sn3 distance (2.412 Å) is 12.8% shorter than the sum of the atomic radii [Standard reference], implying that these atoms mutually exclude each other. The first structural variant assumes a disordered subcell A1 in which Sn3 atoms form Sn4 tetrahedra by occupying only four of the eight corners of the Sn8 cube. The second structural variant assumes a disordered subcell A2, which is the same as subcell A1 but with the other set of cube corners occupied.
The quaternary phase (II) is more ordered than the ternary phase. Subcell A contains atoms Tm1, Li1, Co1, Sn1 and Sn3, but for [no?] Sn2 atoms. Subcell B contains atoms Tm1, Li1, Co1, Sn1 and Sn2, but for [no?] Sn3 atoms. A projection of the A and B unit cells, the coordination polyhedra of the atoms and the coordination polyhedron around the Sn1—Sn1 dumbbells for (II) are shown in Fig. 1. The first coordination sphere was taken into account (r1 + r2 + 0.5 in Å, where r1 and r2 are the atomic radii of the atoms) under the additional condition of convexity of the polyhedron. Therefore, in some cases (for Sn3) the condition changed to (r1 + r2 + 0.7) Å. Detailed crystal chemical analysis shows that atoms Sn1 and Sn2 are enclosed in a strongly deformed bicapped hexagonal prism with a coordination number (CN) of 14 and a monocapped hexagonal prism with CN = 13, respectively. The Sn1—Sn1 covalent dumbbells are surrounded by 20 atoms (12 Sn, four Co, two Li and two Tm), with a maximum distance to the central atom of 3.3 Å [For which?]. A typical 12-vertex polyhedron is observed for the Sn3 atoms in both A1 and A2 subcells. The Co atom has a tetragonal antiprismatic coordination polyhedron with one additional capping atom (CN = 9) in the case of subcell A2, and a seven-vertex polyhedron in subcell A1. In both phases, the Tm1 atoms are surrounded by 18 adjacent atoms in the form of a pseudo-Frank–Kasper polyhedron. The typical 16-vertex Frank–Kasper polyhedron is observed for the Tm2 [for (I)] and Li [for (II)] atoms. In these polyhedra, the Tm2 or Li atoms are surrounded only by Sn atoms, forming [TmSn16] [for (I)] or [LiSn16] [for (II)] clusters. Earlier, we also observed that, in the binary phase LaZn4, the La atom was surrounded only by Zn atoms, forming an 18-vertex cluster (Oshchapovsky et al., 2012). The packing of the 16-vertex clusters and 18-vertex pseudo-Frank–Kasper polyhedra in the unit cell of both structures [Added text OK?] is shown in Fig. 2.
Crystal chemical analysis shows that phases (I) and (II) belong to the structural family (Fig. 3) derived from the cubic Cr23C6 structure type (Bowman et al., 1972). The Mg3Ni20B6 (Stadelmaier et al., 1963) and W2Cr21C6 (Voroshilov & Kuz'ma, 1966) structure types are ternary ordered variants of binary Cr23C6. Structures (I) and (II), as well as Tb4.6Rh6Sn18.4 (Miraglia et al., 1987) and Tb5Rh6Sn17 (Vandenberg, 1980), belong to the disordered variants of this family. In contrast with other disordered variants, the last phase [Which one exactly?] crystallizes in the noncentrosymmetric space group F43m. The transition from a centrosymmetric (space group Fm3m) to a noncentrosymmetric structure is caused by uncoupling of the 32f site into two 16e sites, and of 8c into two 4c and 4d sites.
The electronic structure of the title compounds was calculated using the tight-binding linear muffin-tin orbital (TB–LMTO) method in the atomic spheres approximation (TB–LMTO–ASA; Andersen, 1975; Andersen & Jepsen, 1984; Andersen et al., 1985, 1986), using the experimental crystallographic data which are presented here. The exchange and correlation were interpreted in the local density approximation (von Barth & Hedin, 1972). The TB–LMTO–ASA calculations for both structures were performed on the ordered variant of subcell B, which does not contain any atoms that mutually exclude each other. The Tm, Co and Li atoms donate their electrons to the Sn atoms, and therefore positive charge density can be observed around the Tm, Co and Li atoms, and negative charge density around the Sn atoms (Fig. 4). The presence of Sn—Sn covalent dumbbells is observed. However, the dominant type of bonding in these compounds is metallic. Similar covalent dumbbells were also observed in the La2LiGe6 (Stetskiv, Misztal & Pavlyuk, 2012), La4Mg5Ge6 (Solokha et al., 2012), Tb4Zn5Ge6 (Chumak et al., 2006) and Gd4Zn5Ge6 (Kranenberg et al., 2001) phases.
The total and partial density of states (DOS) for the ordered subcell B of (I) and (II) are shown in Fig. 5. The higher density of electronic states at the Fermi level for (I) than (II) indicates more metallic behaviour for the ternary phase. The common feature of both structures is a very intense peak from the overlapping of the d orbital of Co and the f orbital of Tm and, partially, the p orbital of Sn in the valence band. In the quaternary phase, this intense peak from mixed orbitals lies at -4 eV, and for subcell B of the ternary compound it shifts up to -3 eV. The overlapping of the 3d states of Co and the 4f states of Tm in the conduction and valence bands clearly describe the metallic properties of both phases. The asymmetric Co 3d orbital peak for all cells is probably caused by hybridization of the Co 3d states (the dx2-y2 and dz2 states for Eg, and the dxy, dxz and dyz states for T2g).