Acta Cryst. (2007). E63, i156 [ doi:10.1107/S1600536807027821 ]
Single crystals of lutetium oxide bromide, LuOBr, were obtained accidentally as a by-product of the reaction of lutetium metal, ruthenium powder and lutetium tribromide, LuBr3, in a sealed tantalum container. As is typical for rare-earth oxide halides of the type REOX (RE = rare-earth metal and X = halogen), LuOBr crystallizes in the tetragonal PbFCl structure type (matlockite), where Lu, O and Br are situated on positions with 4mm, 
m2 and 4mm symmetry, respectively.
Light-orange, transparent plates of LuOBr were obtained in this special case as a major by-product (35%) from the reaction of lutetium powder (0.092 g, 0.5 mmol; Smart Elements, 99.99%), ruthenium powder (0.022 g, 0.2 mmol; Merck, 99%) and nominally pure LuBr3 (0.150 g, 0.4 mmol). Except for excess starting materials, other products were not identified so far. LuBr3 was prepared by the reaction of Lu2O3 (Chempur, 99.9%) with NH4Br (KMF, 99.5%) (Meyer, 1991), followed by the decomposition of the resulting (NH4)3LuBr6 at 693 K and subsequent sublimation. The reaction was carried out in a He-arc welded tantalum container within a silica jacket at 1273 K for 3 d and tempering at 1073 K for 10 d. Due to their moisture and air sensitivity, reagents and products were handled in an argon-filled glove box (M. Braun, Garching, Germany).
For the present refinement, origin choice 2 for space group P4/nmm was chosen. The highest peak in the final difference Fourier map is 1.03 Å from atom Lu and the deepest hole is 1.14 Å from the same atom.
Data collection: X-AREA (Stoe & Cie, 2001); cell refinement: X-AREA; data reduction: X-AREA; program(s) used to solve structure: SIR92 (Altomare et al., 1993); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 2005); software used to prepare material for publication: SHELXL97.
![[Figure 1]](./wm2121fig1thm.gif)
| Fig. 1. The surrounding of Lu3+ in LuOBr with displacement ellipsoids drawn at the 75% (O, Br) and 80% (Lu) probability level. [Symmetry codes: (i) −x, −y + 1, −z + 1; (ii) x, y + 1, z; (iii) −x − 1, −y + 1, −z + 1; (iv) x − 1, y − 1, z; (v) x − 1, y, z; (vi) x, y − 1, z; (vii) −x, −y + 2, −z + 1]. |
![[Figure 2]](./wm2121fig2thm.gif)
| Fig. 2. Part of the crystal structure of LuOBr, viewed along the a axis. Lu atoms are represented as grey, O as red and Br as brown spheres. |
| LuOBr | Z = 2 |
| Mr = 270.88 | F000 = 228 |
| Tetragonal, P4/nmm | Dx = 7.598 Mg m−3 |
| Hall symbol: -P 4a 2a | Melting point: no K |
| a = 3.7646 (13) Å | Mo Kα radiation λ = 0.71073 Å |
| b = 3.7646 (13) Å | Cell parameters from 1168 reflections |
| c = 8.354 (4) Å | θ = 1.9–28.2º |
| α = 90º | µ = 58.17 mm−1 |
| β = 90º | T = 293 (2) K |
| γ = 90º | Plate, light-orange |
| V = 118.39 (8) Å3 | 0.20 × 0.10 × 0.05 mm |
| Stoe IPDS I diffractometer | 107 independent reflections |
| Radiation source: fine-focus sealed tube | 107 reflections with I > 2σ(I) |
| Monochromator: graphite | Rint = 0.099 |
| T = 293(2) K | θmax = 27.7º |
| φ scans | θmin = 4.9º |
| Absorption correction: numerical [X-RED (Stoe & Cie, 2001) and X-SHAPE (Stoe & Cie, 1999)] | h = −4→4 |
| Tmin = 0.004, Tmax = 0.057 | k = −4→4 |
| 1046 measured reflections | l = −10→10 |
| Refinement on F2 | w = 1/[σ2(Fo2) + (0.0199P)2 + 0.8289P] where P = (Fo2 + 2Fc2)/3 |
| Least-squares matrix: full | (Δ/σ)max < 0.001 |
| R[F2 > 2σ(F2)] = 0.023 | Δρmax = 1.55 e Å−3 |
| wR(F2) = 0.054 | Δρmin = −2.54 e Å−3 |
| S = 1.29 | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
| 107 reflections | Extinction coefficient: 0.019 (3) |
| 10 parameters | |
| Primary atom site location: structure-invariant direct methods | |
| Secondary atom site location: difference Fourier map |
| LuOBr | γ = 90º |
| Mr = 270.88 | V = 118.39 (8) Å3 |
| Tetragonal, P4/nmm | Z = 2 |
| a = 3.7646 (13) Å | Mo Kα |
| b = 3.7646 (13) Å | µ = 58.17 mm−1 |
| c = 8.354 (4) Å | T = 293 (2) K |
| α = 90º | 0.20 × 0.10 × 0.05 mm |
| β = 90º |
| Stoe IPDS I diffractometer | 107 independent reflections |
| Absorption correction: numerical [X-RED (Stoe & Cie, 2001) and X-SHAPE (Stoe & Cie, 1999)] | 107 reflections with I > 2σ(I) |
| Tmin = 0.004, Tmax = 0.057 | Rint = 0.099 |
| 1046 measured reflections |
| R[F2 > 2σ(F2)] = 0.023 | Δρmax = 1.55 e Å−3 |
| wR(F2) = 0.054 | Δρmin = −2.54 e Å−3 |
| S = 1.29 | Absolute structure: ? |
| 107 reflections | Flack parameter: ? |
| 10 parameters | Rogers parameter: ? |
Experimental. The absorption correction (X-RED; Stoe & Cie, 2001) was performed after optimizing the crystal shape using X-SHAPE (Stoe & Cie, 1999). A suitable single-crystal was carefully selected under a polarizing microscope and mounted in a glass capillary. The scattering intensities were collected on an imaging plate diffractometer (IPDS I, Stoe & Cie) equipped with a fine focus sealed tube X-ray source (Mo Kα, λ = 0.71073 Å) operating at 50 kV and 40 mA. Intensity data for the title compound were collected at room temperature by φ scans in 100 frames (0 < φ < 200°, Δφ = 2°, exposure time of 10 min) in the 2 Θ range 3.8 to 56.3°. Structure solution and refinement were carried out using the programs SIR92 (Altomare et al., 1993) and SHELXL97 (Sheldrick, 1997). A numerical absorption correction (X-RED (Stoe & Cie, 2001) was applied after optimization of the crystal shape (X-SHAPE (Stoe & Cie, 1999)). The last cycles of refinement included atomic positions and anisotropic parameters for all atoms. The final difference maps were free of any chemically significant features. The refinement was based on F2 for ALL reflections. |
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 > 2sigma(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 | ||
| Lu | −0.2500 | 0.7500 | 0.36724 (9) | 0.0082 (4) | |
| Br | 0.2500 | 1.2500 | 0.1718 (3) | 0.0158 (5) | |
| O | −0.2500 | 0.2500 | 0.5000 | 0.009 (2) |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| Lu | 0.0034 (4) | 0.0034 (4) | 0.0178 (5) | 0.000 | 0.000 | 0.000 |
| Br | 0.0142 (6) | 0.0142 (6) | 0.0190 (9) | 0.000 | 0.000 | 0.000 |
| O | 0.005 (3) | 0.005 (3) | 0.016 (5) | 0.000 | 0.000 | 0.000 |
| Lu—Oi | 2.1847 (7) | Lu—Lui | 3.4650 (14) |
| Lu—Oii | 2.1847 (7) | Lu—Luviii | 3.4650 (13) |
| Lu—Oiii | 2.1847 (7) | Lu—Luiii | 3.4650 (14) |
| Lu—O | 2.1847 (7) | Br—Luix | 3.1228 (15) |
| Lu—Briv | 3.1228 (15) | Br—Luii | 3.1228 (15) |
| Lu—Br | 3.1228 (15) | Br—Lux | 3.1228 (15) |
| Lu—Brv | 3.1228 (15) | O—Lui | 2.1847 (7) |
| Lu—Brvi | 3.1228 (15) | O—Luvi | 2.1847 (7) |
| Lu—Luvii | 3.4650 (14) | O—Luiii | 2.1847 (7) |
| Oi—Lu—Oii | 75.07 (2) | O—Lu—Lui | 37.533 (10) |
| Oi—Lu—Oiii | 118.99 (4) | Briv—Lu—Lui | 109.55 (3) |
| Oii—Lu—Oiii | 75.07 (2) | Br—Lu—Lui | 109.55 (3) |
| Oi—Lu—O | 75.07 (2) | Brv—Lu—Lui | 171.72 (5) |
| Oii—Lu—O | 118.99 (4) | Brvi—Lu—Lui | 71.33 (5) |
| Oiii—Lu—O | 75.07 (2) | Luvii—Lu—Lui | 65.81 (3) |
| Oi—Lu—Briv | 141.696 (9) | Oi—Lu—Luviii | 98.23 (4) |
| Oii—Lu—Briv | 141.696 (9) | Oii—Lu—Luviii | 37.533 (10) |
| Oiii—Lu—Briv | 75.29 (3) | Oiii—Lu—Luviii | 37.533 (10) |
| O—Lu—Briv | 75.29 (3) | O—Lu—Luviii | 98.23 (4) |
| Oi—Lu—Br | 75.29 (3) | Briv—Lu—Luviii | 109.55 (3) |
| Oii—Lu—Br | 75.29 (3) | Br—Lu—Luviii | 109.55 (3) |
| Oiii—Lu—Br | 141.696 (9) | Brv—Lu—Luviii | 71.33 (5) |
| O—Lu—Br | 141.696 (9) | Brvi—Lu—Luviii | 171.72 (5) |
| Briv—Lu—Br | 116.95 (8) | Luvii—Lu—Luviii | 65.81 (3) |
| Oi—Lu—Brv | 141.696 (9) | Lui—Lu—Luviii | 100.39 (5) |
| Oii—Lu—Brv | 75.29 (3) | Oi—Lu—Luiii | 98.23 (4) |
| Oiii—Lu—Brv | 75.29 (3) | Oii—Lu—Luiii | 98.23 (4) |
| O—Lu—Brv | 141.696 (9) | Oiii—Lu—Luiii | 37.533 (10) |
| Briv—Lu—Brv | 74.13 (4) | O—Lu—Luiii | 37.533 (10) |
| Br—Lu—Brv | 74.13 (4) | Briv—Lu—Luiii | 71.33 (5) |
| Oi—Lu—Brvi | 75.29 (3) | Br—Lu—Luiii | 171.72 (5) |
| Oii—Lu—Brvi | 141.696 (9) | Brv—Lu—Luiii | 109.55 (3) |
| Oiii—Lu—Brvi | 141.696 (9) | Brvi—Lu—Luiii | 109.55 (3) |
| O—Lu—Brvi | 75.29 (3) | Luvii—Lu—Luiii | 100.39 (5) |
| Briv—Lu—Brvi | 74.13 (4) | Lui—Lu—Luiii | 65.81 (3) |
| Br—Lu—Brvi | 74.13 (4) | Luviii—Lu—Luiii | 65.81 (3) |
| Brv—Lu—Brvi | 116.95 (8) | Luix—Br—Luii | 74.13 (4) |
| Oi—Lu—Luvii | 37.533 (10) | Luix—Br—Lux | 74.13 (4) |
| Oii—Lu—Luvii | 37.533 (10) | Luii—Br—Lux | 116.95 (8) |
| Oiii—Lu—Luvii | 98.23 (4) | Luix—Br—Lu | 116.95 (8) |
| O—Lu—Luvii | 98.23 (4) | Luii—Br—Lu | 74.13 (4) |
| Briv—Lu—Luvii | 171.72 (5) | Lux—Br—Lu | 74.13 (4) |
| Br—Lu—Luvii | 71.33 (5) | Lui—O—Luvi | 104.93 (2) |
| Brv—Lu—Luvii | 109.55 (3) | Lui—O—Luiii | 118.99 (4) |
| Brvi—Lu—Luvii | 109.55 (3) | Luvi—O—Luiii | 104.93 (2) |
| Oi—Lu—Lui | 37.533 (10) | Lui—O—Lu | 104.93 (2) |
| Oii—Lu—Lui | 98.23 (4) | Luvi—O—Lu | 118.99 (4) |
| Oiii—Lu—Lui | 98.23 (4) | Luiii—O—Lu | 104.93 (2) |
| Symmetry codes: (i) −x, −y+1, −z+1; (ii) x, y+1, z; (iii) −x−1, −y+1, −z+1; (iv) x−1, y−1, z; (v) x−1, y, z; (vi) x, y−1, z; (vii) −x, −y+2, −z+1; (viii) −x−1, −y+2, −z+1; (ix) x+1, y+1, z; (x) x+1, y, z. |
| Lu—O | 2.1847 (7) | Lu—Lui | 3.4650 (14) |
| Lu—Br | 3.1228 (15) |
| Symmetry codes: (i) −x, −y+2, −z+1. |
This work was supported by the Deutsche Forschungsgemeinschaft (DFG), SFB 608 (Complex transition metal compounds with spin and charge degrees of freedom and disorder).
Altomare, A., Cascarano, G., Giacovazzo, C. & Guagliardi, A. (1993). J. Appl. Cryst. 26, 343–350.
Brandenburg, K. (2005). DIAMOND. Version 3.0d. Bonn, Germany.
Mayer, I., Zolotov, S. & Kassierer, F. (1965). Inorg. Chem. 4, 1637–1639.
Meyer, G. (1991). Synthesis of Lanthanide and Actinide Compounds, edited by G. Meyer & L. R. Morss, pp. 135–144. Dordrecht: Kluwer.
Sheldrick, G. M. (1997). SHELXL97. University of Göttingen, Germany.
Stoe & Cie (1999). X-SHAPE. Version 1.06. Stoe & Cie, Darmstadt, Germany.
Stoe & Cie (2001). X-RED (Version 1.22) and X-AREA (Version 1.15). Stoe & Cie GmbH, Darmstadt, Germany.
In conproportionation reactions of rare-earth trihalides REX3 with their respective metals (frequently with the addition of a transition metal), the oxide halides REOX often appear as a few single crystals as by-products. Except for impurities from the reaction containers, e.g. tantalum, this may be due to impure anhydrous rare-earth trihalides REX3 which are generated by the so-called ammonium halide route (Meyer, 1991).
LuOBr was obtained in a reaction of lutetium metal, ruthenium powder and nominally pure lutetium tribromide, LuBr3, in a tantalum container at 1273 K. It crystallizes with the tetragonal PbFCl- (matlockite) type of structure, in which a central sheet of oxygen atoms is flanked by two sheets of bromine atoms. Between these Br—O—Br sheets, Lu3+ is surrounded by four oxygen and four bromine atoms in a distorted square antiprism with Lu—O distances of 2.1847 (7) Å and Lu—Br distances of 3.1228 (15) Å (Figs. 1, 2). There is an additional bromine atom capping one of the square faces at a distance of 3.851 (3) Å. The cell parameters obtained from the single-crystal study show no significant differences to those of a previous powder work (a = 3.770, c = 8.387 Å; Mayer et al., 1965).