Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536803013242/br6104sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536803013242/br6104Isup2.hkl |
Key indicators
- Single-crystal X-ray study
- T = 298 K
- Mean (Yb-Se) = 0.001 Å
- R factor = 0.033
- wR factor = 0.074
- Data-to-parameter ratio = 45.3
checkCIF results
No syntax errors found ADDSYM reports no extra symmetry
Yb2Se3 was obtained from a reaction of elemental ytterbium and selenium in a tin flux. The mixture was annealed at 1173 K over a period of 4 d, and then slowly cooled (3 K h−1) to room temperature. Yb2Se3 crystallized in the form of black block-shaped crystals.
Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 1999); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997).
Fig. 1. A projection of Yb2Se3 along the a axis. Displacement ellipsoids are drawn at the 99.9% probability level. Colour code: blue Yb and yellow Se. |
Yb2Se3 | F(000) = 3872 |
Mr = 582.96 | Dx = 7.152 Mg m−3 |
Orthorhombic, Fddd | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -F 2uv 2vw | Cell parameters from 5337 reflections |
a = 8.0183 (7) Å | θ = 3.2–35.0° |
b = 11.272 (1) Å | µ = 54.32 mm−1 |
c = 23.961 (2) Å | T = 298 K |
V = 2165.7 (3) Å3 | Block, black |
Z = 16 | 0.01 × 0.01 × 0.01 mm |
Bruker SMART APEX CCD diffractometer | 1179 independent reflections |
Radiation source: fine-focus sealed tube | 937 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.049 |
ϕ and ω scans | θmax = 35.0°, θmin = 3.2° |
Absorption correction: ψ scan (SAINT; Bruker, 1999) | h = −12→12 |
Tmin = 0.487, Tmax = 0.581 | k = −17→17 |
5337 measured reflections | l = −32→38 |
Refinement on F2 | Primary atom site location: isomorphous structure methods |
Least-squares matrix: full | w = 1/[σ2(Fo2) + (0.0244P)2] where P = (Fo2 + 2Fc2)/3 |
R[F2 > 2σ(F2)] = 0.033 | (Δ/σ)max = 0.001 |
wR(F2) = 0.074 | Δρmax = 1.70 e Å−3 |
S = 1.12 | Δρmin = −3.52 e Å−3 |
1179 reflections | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
26 parameters | Extinction coefficient: 0.000397 (11) |
0 restraints |
Yb2Se3 | V = 2165.7 (3) Å3 |
Mr = 582.96 | Z = 16 |
Orthorhombic, Fddd | Mo Kα radiation |
a = 8.0183 (7) Å | µ = 54.32 mm−1 |
b = 11.272 (1) Å | T = 298 K |
c = 23.961 (2) Å | 0.01 × 0.01 × 0.01 mm |
Bruker SMART APEX CCD diffractometer | 1179 independent reflections |
Absorption correction: ψ scan (SAINT; Bruker, 1999) | 937 reflections with I > 2σ(I) |
Tmin = 0.487, Tmax = 0.581 | Rint = 0.049 |
5337 measured reflections |
R[F2 > 2σ(F2)] = 0.033 | 26 parameters |
wR(F2) = 0.074 | 0 restraints |
S = 1.12 | Δρmax = 1.70 e Å−3 |
1179 reflections | Δρmin = −3.52 e Å−3 |
Experimental. The absorption correction was performed using the SAINT package (Bruker, 1999b); the routine is called SADABS. |
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 | ||
Yb1 | 0.1250 | 0.1250 | 0.041383 (14) | 0.00754 (10) | |
Yb2 | 0.1250 | 0.1250 | 0.377464 (14) | 0.00745 (10) | |
Se1 | 0.37062 (10) | 0.1250 | 0.1250 | 0.00751 (16) | |
Se2 | 0.38115 (7) | 0.12282 (5) | 0.45668 (2) | 0.00758 (13) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Yb1 | 0.00865 (17) | 0.00734 (17) | 0.00664 (17) | −0.00092 (14) | 0.000 | 0.000 |
Yb2 | 0.00657 (16) | 0.00766 (17) | 0.00813 (17) | 0.00168 (11) | 0.000 | 0.000 |
Se1 | 0.0078 (4) | 0.0058 (3) | 0.0090 (4) | 0.000 | 0.000 | 0.0001 (3) |
Se2 | 0.0068 (3) | 0.0085 (3) | 0.0074 (3) | −0.0029 (3) | −0.00142 (17) | 0.00012 (19) |
Yb1—Se2i | 2.7943 (6) | Yb2—Se2vii | 2.8086 (7) |
Yb1—Se2ii | 2.7943 (6) | Yb2—Se1i | 2.8188 (3) |
Yb1—Se1 | 2.8095 (6) | Yb2—Se1ii | 2.8188 (2) |
Yb1—Se1iii | 2.8095 (6) | Se1—Yb1viii | 2.8095 (6) |
Yb1—Se2iv | 2.8184 (6) | Se1—Yb2i | 2.8188 (3) |
Yb1—Se2v | 2.8184 (6) | Se1—Yb2ix | 2.8188 (2) |
Yb2—Se2 | 2.7967 (6) | Se2—Yb1i | 2.7943 (6) |
Yb2—Se2iii | 2.7967 (6) | Se2—Yb2vii | 2.8086 (6) |
Yb2—Se2vi | 2.8086 (7) | Se2—Yb1x | 2.8184 (6) |
Se2i—Yb1—Se2ii | 178.09 (3) | Se2—Yb2—Se2iii | 94.52 (3) |
Se2i—Yb1—Se1 | 90.028 (12) | Se2—Yb2—Se2vi | 176.864 (19) |
Se2ii—Yb1—Se1 | 88.610 (13) | Se2iii—Yb2—Se2vi | 88.614 (17) |
Se2i—Yb1—Se1iii | 88.610 (13) | Se2—Yb2—Se2vii | 88.614 (17) |
Se2ii—Yb1—Se1iii | 90.028 (12) | Se2iii—Yb2—Se2vii | 176.864 (19) |
Se1—Yb1—Se1iii | 89.02 (3) | Se2vi—Yb2—Se2vii | 88.25 (2) |
Se2i—Yb1—Se2iv | 89.486 (17) | Se2—Yb2—Se1i | 89.788 (17) |
Se2ii—Yb1—Se2iv | 91.888 (18) | Se2iii—Yb2—Se1i | 91.841 (17) |
Se1—Yb1—Se2iv | 179.236 (16) | Se2vi—Yb2—Se1i | 90.136 (17) |
Se1iii—Yb1—Se2iv | 91.562 (18) | Se2vii—Yb2—Se1i | 88.141 (17) |
Se2i—Yb1—Se2v | 91.888 (18) | Se2—Yb2—Se1ii | 91.841 (17) |
Se2ii—Yb1—Se2v | 89.486 (17) | Se2iii—Yb2—Se1ii | 89.788 (17) |
Se1—Yb1—Se2v | 91.562 (18) | Se2vi—Yb2—Se1ii | 88.141 (17) |
Se1iii—Yb1—Se2v | 179.236 (16) | Se2vii—Yb2—Se1ii | 90.136 (17) |
Se2iv—Yb1—Se2v | 87.86 (3) | Se1i—Yb2—Se1ii | 177.600 (14) |
Symmetry codes: (i) −x+1/2, −y, −z+1/2; (ii) x−1/4, y+1/4, −z+1/2; (iii) −x+1/4, −y+1/4, z; (iv) x−1/2, y, z−1/2; (v) −x+3/4, −y+1/4, z−1/2; (vi) x−1/2, −y+1/4, −z+3/4; (vii) −x+3/4, y, −z+3/4; (viii) −x+1/4, y, −z+1/4; (ix) x+1/4, −y+1/2, z−1/4; (x) x+1/2, y, z+1/2. |
Experimental details
Crystal data | |
Chemical formula | Yb2Se3 |
Mr | 582.96 |
Crystal system, space group | Orthorhombic, Fddd |
Temperature (K) | 298 |
a, b, c (Å) | 8.0183 (7), 11.272 (1), 23.961 (2) |
V (Å3) | 2165.7 (3) |
Z | 16 |
Radiation type | Mo Kα |
µ (mm−1) | 54.32 |
Crystal size (mm) | 0.01 × 0.01 × 0.01 |
Data collection | |
Diffractometer | Bruker SMART APEX CCD diffractometer |
Absorption correction | ψ scan (SAINT; Bruker, 1999) |
Tmin, Tmax | 0.487, 0.581 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 5337, 1179, 937 |
Rint | 0.049 |
(sin θ/λ)max (Å−1) | 0.807 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.033, 0.074, 1.12 |
No. of reflections | 1179 |
No. of parameters | 26 |
Δρmax, Δρmin (e Å−3) | 1.70, −3.52 |
Computer programs: SMART (Bruker, 2000), SAINT (Bruker, 1999), SAINT, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997).
Yb1—Se2i | 2.7943 (6) | Yb2—Se2 | 2.7967 (6) |
Yb1—Se2ii | 2.7943 (6) | Yb2—Se2iii | 2.7967 (6) |
Yb1—Se1 | 2.8095 (6) | Yb2—Se2vi | 2.8086 (7) |
Yb1—Se1iii | 2.8095 (6) | Yb2—Se2vii | 2.8086 (7) |
Yb1—Se2iv | 2.8184 (6) | Yb2—Se1i | 2.8188 (3) |
Yb1—Se2v | 2.8184 (6) | Yb2—Se1ii | 2.8188 (2) |
Symmetry codes: (i) −x+1/2, −y, −z+1/2; (ii) x−1/4, y+1/4, −z+1/2; (iii) −x+1/4, −y+1/4, z; (iv) x−1/2, y, z−1/2; (v) −x+3/4, −y+1/4, z−1/2; (vi) x−1/2, −y+1/4, −z+3/4; (vii) −x+3/4, y, −z+3/4. |
The sesquichalcogenides of the rare earth elements adopt different structure types. While the La–Gd chalcogenides crystallize in defect variants of the Th3P4 type (Mauricot et al., 1995), Yb2S3 adopts the α-Al2O3 structure (El Fadli et al., 1994). Based on powder diffractograms, the Sc, Y and Dy–Yb selenides (Dismukes & White, 1965; Flahaut et al., 1965) were reported to form the Sc2S3 structure (Tremblet et al., 1963). The cell dimensions for Yb2Se3 (orthorhombic system) were determined by Dismukes & White (1965) to be a = 11.274 Å, b = 8.021 Å, c = 23.98 Å and V = 2168.5 Å, and by Flahaut et al. (1965) to be a = 11.27 Å, b = 8.02 Å, c = 23.96 Å and V = 2165.6 Å. The atomic positions of Yb2Se3 were not refined in either case; Flahaut et al. (1965) merely extrapolated them from the ideal NaCl structure type. Our single-crystal structure study on Yb2Se3 confirms the suggested Sc2S3 type, and delivers crystallographic details with high accuracy. It is evident that the shifts from the NaCl structure are significant; e.g. the x parameters of Se1 and Se2 are not 3/8 = 0.375, but 0.37062 (10) for Se1 and 0.38115 (7) for Se2. This is reflected in deviations from the ideal Se—Yb—Se bond angles of up to 4.5° and Yb—Se bond lengths varying from 2.7943 (6) to 2.8184 (6) Å (Yb1) and from 2.7967 (6) to 2.8188 (3) Å (Yb2).