Single-crystal X-ray structure analysis revealed that Lu4Al2O9 is isostructural with Eu4Al2O9 and contains Lu atoms in six- and sevenfold coordination, together with tetrahedral Al atoms.
Keywords: crystal structure, Lu4Al2O9, lutetium aluminate monoclinic (LUAM), rare-earth aluminate, Lu2O3-Al2O3 system, single-crystal X-ray diffraction
Abstract
The crystal structure of the title compound containing lutetium, the last element in the lanthanide series, was determined using a single crystal prepared by heating a pressed pellet of a 2:1 molar ratio mixture of Lu2O3 and Al2O3 powders in an Ar atmosphere at 2173 K for 4 h. Lu4Al2O9 is isostructural with Eu4Al2O9 and composed of Al2O7 ditetrahedra and Lu-centered six- and sevenfold oxygen polyhedra. The unit-cell volume, 787.3 (3) Å3, is the smallest among the volumes of the rare-earth (RE) aluminates, RE 4Al2O9. The crystal studied was refined as a two-component pseudo-merohedric twin.
Chemical context
In the Al2O3-Lu2O3 system, where Lu has the largest atomic number among the rare-earth elements (RE), the following three phases have been reported: Lu3Al5O12, LuAlO3, and Lu4Al2O9. These phases have been actively investigated as host materials, not only for phosphors (Ding et al., 2011 ▸; Xiang et al., 2016 ▸; Wang et al., 2018 ▸), but also for scintillators, owing to their large radiation absorption cross sections arising from the presence of Lu. Various scintillation properties of Ce- and Pr-doped Lu3Al5O12 and LuAlO3 crystals have been characterized (Wojtowicz, 1999 ▸; Nikl, 2000 ▸; Wojtowicz et al., 2006 ▸; Nikl et al., 2013 ▸), and the luminescence properties of Ce- and Pr-doped Lu4Al2O9 evaluated (Lempicki et al., 1996 ▸; Zhang et al., 1997 ▸, Zhang et al., 1998 ▸; Drozdowski et al., 2005 ▸). The crystal structures of the lutetium aluminates Lu3Al5O12 (Euler & Bruce, 1965 ▸) and LuAlO3 (Dernier & Maines, 1971 ▸; Shishido et al., 1995 ▸) have been determined as garnet-type (LUAG) and perovskite-type (LUAP), respectively. However, to date, there have been no reports of the lattice constants of Lu4Al2O9, although Shirvinskaya & Popova (1977 ▸) treated it as isotypic with Y4Al2O9 and have reported the d-spacings and relative peak intensities in the powder X-ray diffraction pattern (PDF#00-033-0844).
Many REAl2O9 compounds have been investigated in detail. After Warshaw & Roy (1959 ▸) first reported the existence of Y4Al2O9, Reed & Chase (1962 ▸) determined the space group of this material as P21/c using X-ray Weissenberg and precession photography. Christensen & Hazell (1991 ▸) later determined the crystal structure of Y4Al2O9 using powder synchrotron X-ray and neutron diffraction. Brandle & Steinfink (1969 ▸) also prepared crystals of REAl2O9 (RE = Sm, Gd, Eu, Dy, Ho) and determined the crystal structure of Eu4Al2O9 using X-ray diffraction.
The lattice parameters of RE 4Al2O9 have previously been reported for RE = Y (Lehmann et al., 1987 ▸; Reed & Chase, 1962 ▸; Christensen & Hazell, 1991 ▸; Yamane et al., 1995b ▸; Talik et al., 2016 ▸), La (Dohrup et al., 1996 ▸), Pr (Dohrup et al., 1996 ▸), Nd (Dohrup et al., 1996 ▸), Sm (Brandle & Steinfink, 1969 ▸; Mizuno et al., 1977a ▸; Yamane et al., 1995a ▸), Eu (Brandle & Steinfink, 1969 ▸; Mizuno et al., 1977b ▸; Yamane et al., 1995a ▸), Gd (Brandle & Steinfink, 1969 ▸; Mizuno et al., 1977b ▸; Yamane et al., 1995a ▸; Dohrup et al., 1996 ▸; Martín-Sedeño et al., 2006 ▸), Tb (Jero & Kriven, 1988 ▸; Yamane et al., 1995a ▸; Dohrup et al., 1996 ▸; Li et al., 2009 ▸), Dy (Brandle & Steinfink, 1969 ▸; Mizuno et al., 1978 ▸; Yamane et al., 1995a ▸), Ho (Brandle & Steinfink, 1969 ▸; Mizuno, 1979 ▸; Yamane et al., 1995a ▸), Er (Mizuno, 1979 ▸; Yamane et al., 1995a ▸), Tm (Yamane et al., 1995a ▸), and Yb (Mizuno & Noguchi, 1980 ▸; Yamane et al., 1995a ▸).
Wu & Pelton (1992 ▸) investigated the phase diagram of the Lu2O3–Al2O3 system and showed that Lu4Al2O9 melted congruently at 2313 K under an inert atmosphere. Petrosyan et al. (2006 ▸) studied the same system under a reducing atmosphere and reported that Lu4Al2O9 could be formed by reaction of Lu2O3 and Lu3Al5O12 at 1923 K, but decomposed into Lu2O3 and a melt at 2273 K. Subsequently, Petrosyan et al. (2013 ▸) observed incongruent melting of Lu4Al2O9 at 2123 K under an Ar / 2% H2 atmosphere using differential thermal analysis (DTA). Klimm (2010 ▸) employed DTA to investigate LuAlO3 melting behavior in a 5 N pure Ar flow and concluded that the congruent and incongruent melting of LuAlO3 depended on the atmospheric conditions. The author also concluded that the phase diagram at around Lu:Al = 1:1 under an inert atmosphere, previously reported by Wu & Pelton (1992 ▸), is correct. Yamane et al. (1995a ▸) reported that only a very small amount of Lu4Al2O9 can be obtained by reactions in air at 1673–2073 K, even though RE 4Al2O9 (RE = Y, Sm–Yb) can be synthesized under the same conditions.
Following these reports, the present authors also attempted to synthesize Lu4Al2O9 by heating a 2:1 molar ratio powder mixture of Lu2O3 and Al2O3 at 2073 K for 2 h in air, but the sample obtained was a mixture of LuAlO3 and Lu2O3 (see Fig. S1a in the supporting information). The method used to prepare the single crystals of Lu4Al2O9 used for the present diffraction study is described below.
Structural commentary
X-ray diffraction spots from the Lu4Al2O9 single crystal were indexed on the basis of a monoclinic unit cell with lattice parameters: a = 7.236 (2) Å, b = 10.333 (2) Å, c = 11.096 (3) Å, and β = 108.38 (2)°. As shown in Fig. 1 ▸, the unit-cell volume of Lu4Al2O9 calculated from these parameters lies on the extrapolated line of RE 4Al2O9 volumes plotted against the effective ionic radii for sixfold coordination of the trivalent rare-earth anions (RE 3+) (Shannon, 1976 ▸). In other words, Lu4Al2O9 containing Lu, which has the smallest effective ionic radius of the RE atoms, has the smallest unit-cell volume in the RE 4Al2O9 series, in line with predictions arising from the lanthanide contraction.
Figure 1.
Unit-cell volume of RE 4Al2O9 versus effective ionic radius for the trivalent rare-earth anion (RE 3+) with sixfold coordination.
The crystal structure of Lu4Al2O9 (space group P21/c), determined using Eu4Al2O9 (Brandle & Steinfink, 1969 ▸) as the starting model, contains two crystallographically distinct Al sites, four Lu sites, and nine O sites. The two Al sites are tetrahedrally coordinated by oxygen atoms. The two Al tetrahedra are connected through a shared O5 atom, forming an Al2O7 ditetrahedral oxy-aluminate group (Fig. 2 ▸). The Al2O7 dimers lie parallel to the a axis, and are related by the c glide symmetry operation (Fig. 3 ▸). The average Al1—O and Al2—O distances in Lu4Al2O9 are 1.744 and 1.756 Å, respectively, which are comparable to values found in Eu4Al2O9 (1.741 and 1.755 Å, Brandle & Steinfink, 1969 ▸) and Y4Al2O9 (1.739 and 1.769 Å, Lehmann et al., 1987 ▸). The bond-valence sums (BVS; Brown & Altermatt, 1985 ▸) calculated using the Al—O distances and bond-valence parameters recently reported by Gagne & Hawthorne (2015 ▸) (r 0 =1.634 Å, b = 0.39) are 3.02 and 2.93 for Al1 and Al2, respectively. These BVS values are close to those expected for trivalent Al. The Al1—O5—Al2 angle of the Al2O7 dimer is 134.9 (3)°, which is smaller than the corresponding angles in Eu4Al2O9 (141.9°; Brandle & Steinfink, 1969 ▸) and Y4Al2O9 (137.6°; Lehmann et al., 1987 ▸).
Figure 2.
The atomic arrangement of Lu4Al2O9 depicted with displacement ellipsoids at the 99% probability level. [Symmetry codes: (i) 1 − x, −y, 1 − z; (ii) −x, −y, 1 − z; (iii) x − 1, y, z; (iv) 1 + x, −y +
, z −
; (v) x + 1, y, z; (vi) x, −y +
, z −
; (vii) x, −y +
, z +
; (viii) x, y, z − 1.]
Figure 3.
The crystal structure of Lu4Al2O9 highlighting the Al2O7 ditetrahedra viewed down the b axis (upper), and the Al2O7 ditetrahedra and Lu-centered polyhedra viewed down the a axis (lower).
Of the four crystallographically distinct Lu atoms, Lu1 and Lu3 are coordinated by seven oxygen atoms with five Lu—O distances in the range 2.219 (5)–2.344 (5) Å and two in the range 2.461 (6)–2.573 (6) Å. The remaining Lu atoms, Lu2 and Lu4, are coordinated by six oxygen atoms in distorted octahedra with Lu—O distances in the range 2.172 (6)–2.337 (6) Å.
The averages Lu—O distances for the six-fold coordinated Lu atoms in Lu4Al2O9 are 2.250 and 2.260 Å for Lu2 and Lu4, respectively. These values are 0.02–0.10 Å shorter than those for the LuO6 octahedra found in Lu3Al5O12 (2.352 Å; Euler & Bruce, 1965 ▸) and LuAlO3 (2.330 Å; Shishido et al., 1995 ▸).
The average values for the Eu—O and Y—O distances in Eu4Al2O9 and Y4Al2O9 lie in the ranges 2.328–2.439 Å (Brandle & Steinfink, 1969 ▸) and 2.286–2.387 Å (Lehmann et al., 1987 ▸), respectively. The differences between the RE—O lengths in RE 4Al2O9 when RE = Eu and Lu (0.07–0.09 Å), and when RE = Y and Lu (0.02–0.05 Å) correspond to the differences between VI r Eu − VI r Lu (0.086 Å) and VI r Y − VI r Lu (0.039 Å), where VI r Eu, VI r Lu, and VI r Lu are the effective ionic radii in sixfold coordination of Lu3+ (0.861 Å), Eu3+ (0.947 Å), and Y3+ (0.900 Å), respectively (Shannon, 1976 ▸). The BVS for Lu1, Lu2, Lu3, and Lu4, calculated using the bond-valence parameters (r 0 = 1.939 Å, b = 0.403) of Gagné & Hawthorne (2015 ▸), are 2.766, 2.796, 2.642, and 2.714, respectively, which are smaller than the expected valence value of +3 for the Lu atoms. The polyhedral volumes of Lu1O7 (18.18 Å3), Lu2O6 (14.29 Å3), Lu3O7 (18.56 Å3), and Lu4O6 (14.24 Å3) are 1.1–1.7 Å3 and 0.5–0.8 Å3 smaller than those for Eu4Al2O9 (Eu1O7:19.85 Å3, Eu2O6:15.38 Å3, Eu3O7:20.14 Å3, and Eu4O6:15.71 Å3) and for Y4Al2O9 (Y1O7:18.66 Å3, Y2O6:14.77 Å3, Y3O7:19.33 Å3, and Y4O6:14.98 Å3), respectively. These differences in polyhedral volumes correlate with the differences in ionic radii of the lanthanides.
Synthesis and crystallization
The starting powders Al2O3 (Sumitomo Chemicals, AKP20, 99.99%) and Lu2O3 (Nippon Yttrium, 99.999%) were mixed in a molar ratio of Lu:Al = 2:1, ground with ethanol in an agate mortar, and pressed into a pellet. The pellet was placed in a BN crucible with an inner diameter of 18 mm and a height of 20 mm. The BN crucible was covered with a BN lid, and heated in a chamber with a carbon heater (Shimadzu Mectem, Inc., VESTA). The pellet was heated slowly under vacuum (∼10 −2 Pa) from room temperature to 1273 K. During the 5 min. hold at 1273 K, the chamber was filled with Ar (99.9995%) up to 0.15 MPa. The temperature was then raised to 2173 K at a heating rate of 300 Kh−1. After being held at 2173 K for 4 h, the sample was cooled to 1473 K at a rate of 20 Kh−1, and then to room temperature by shutting off the heater. A part of the obtained sample was pulverized in the agate mortar, and powder X-ray diffraction measurements (Bruker D2 Phaser, Cu Kα radiation) confirmed that the major crystalline phase present in the sample was Lu4Al2O9, together with small amounts of LuAlO3 and unreacted Lu2O3 (Fig. S1a). Colorless crystals of Lu4Al2O9 were selected for single-crystal X-ray diffraction studies.
Refinement
Crystal data, data collection and structure refinement details are summarized in Table 1 ▸. The Eu atoms in the rare-earth metal sites in the structural model of Eu4Al2O9 (Brandle & Steinfink, 1969 ▸) were replaced by Lu atoms to generate the initial model. Several iterations of refinement yielded an R value of 10.07% and a residual electron density of ∼10 e Å−3. A subsequent refinement, performed by implementing the (100) twin plane observed in a study of Y4Al2O9 (Yamane et al., 1995b ▸), yielded an R(F 2 > 2σ(F 2)) value of 1.92% with an approximate volume ratio of 6:4 for the twin domains.
Table 1. Experimental details.
| Crystal data | |
| Chemical formula | Lu4Al2O9 |
| M r | 897.84 |
| Crystal system, space group | Monoclinic, P21/c |
| Temperature (K) | 301 |
| a, b, c (Å) | 7.2360 (11), 10.3330 (19), 11.096 (3) |
| β (°) | 108.381 (11) |
| V (Å3) | 787.3 (3) |
| Z | 4 |
| Radiation type | Mo Kα |
| μ (mm−1) | 49.97 |
| Crystal size (mm) | 0.12 × 0.05 × 0.04 |
| Data collection | |
| Diffractometer | Bruker D8 QUEST |
| Absorption correction | Multi-scan (SADABS; Bruker, 2016 ▸) |
| T min, T max | 0.451, 0.746 |
| No. of measured, independent and observed [I > 2σ(I)] reflections | 32672, 2795, 2719 |
| R int | 0.035 |
| (sin θ/λ)max (Å−1) | 0.748 |
| Refinement | |
| R[F 2 > 2σ(F 2)], wR(F 2), S | 0.019, 0.043, 1.17 |
| No. of reflections | 2795 |
| No. of parameters | 138 |
| Δρmax, Δρmin (e Å−3) | 1.49, −1.81 |
Supplementary Material
Crystal structure: contains datablock(s) I. DOI: 10.1107/S2056989020005757/cq2036sup1.cif
Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989020005757/cq2036Isup2.hkl
Figure S1. Powder XRD patterns of samples prepared (a) under air and (b) under Ar. DOI: 10.1107/S2056989020005757/cq2036sup3.tif
CCDC reference: 1999289
Additional supporting information: crystallographic information; 3D view; checkCIF report
Acknowledgments
We are grateful to Ms Yuko Suzuki and Ms Mitsuyo Takaishi for their assistance with the high-temperature synthesis.
supplementary crystallographic information
Crystal data
| Lu4Al2O9 | F(000) = 1528 |
| Mr = 897.84 | Dx = 7.575 Mg m−3 |
| Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
| a = 7.2360 (11) Å | Cell parameters from 1294 reflections |
| b = 10.3330 (19) Å | θ = 2.8–38.5° |
| c = 11.096 (3) Å | µ = 49.97 mm−1 |
| β = 108.381 (11)° | T = 301 K |
| V = 787.3 (3) Å3 | Chip, colourless |
| Z = 4 | 0.12 × 0.05 × 0.04 mm |
Data collection
| Bruker D8 QUEST diffractometer | 2719 reflections with I > 2σ(I) |
| Detector resolution: 7.3910 pixels mm-1 | Rint = 0.035 |
| ω and σcans | θmax = 32.1°, θmin = 2.8° |
| Absorption correction: multi-scan (SADABS; Bruker, 2016) | h = −10→10 |
| Tmin = 0.451, Tmax = 0.746 | k = −15→15 |
| 32672 measured reflections | l = −16→16 |
| 2795 independent reflections |
Refinement
| Refinement on F2 | 0 restraints |
| Least-squares matrix: full | w = 1/[σ2(Fo2) + 17.273P] where P = (Fo2 + 2Fc2)/3 |
| R[F2 > 2σ(F2)] = 0.019 | (Δ/σ)max = 0.001 |
| wR(F2) = 0.043 | Δρmax = 1.49 e Å−3 |
| S = 1.17 | Δρmin = −1.81 e Å−3 |
| 2795 reflections | Extinction correction: SHELXL2014/7 (Sheldrick 2015b), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
| 138 parameters | Extinction coefficient: 0.00026 (2) |
Special details
| Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes. |
| Refinement. Refined as a two-component inversion twin |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2)
| x | y | z | Uiso*/Ueq | ||
| Al1 | 0.2142 (4) | 0.1742 (2) | 0.1270 (2) | 0.0058 (4) | |
| Al2 | 0.6551 (4) | 0.1717 (2) | 0.1108 (2) | 0.0059 (4) | |
| Lu1 | 0.52225 (7) | 0.11375 (3) | 0.78409 (2) | 0.00572 (6) | |
| Lu2 | 0.02236 (6) | 0.10027 (3) | 0.80405 (2) | 0.00574 (6) | |
| Lu3 | 0.34172 (7) | 0.12783 (3) | 0.44005 (2) | 0.00605 (6) | |
| Lu4 | 0.83940 (6) | 0.12082 (3) | 0.41774 (3) | 0.00610 (6) | |
| O1 | 0.7934 (8) | 0.2450 (6) | 0.7469 (5) | 0.0102 (11) | |
| O2 | 0.2314 (8) | 0.2439 (5) | 0.7699 (5) | 0.0072 (11) | |
| O3 | 0.2106 (13) | 0.0095 (5) | 0.1516 (5) | 0.0102 (10) | |
| O4 | 0.0720 (8) | 0.2340 (6) | 0.9813 (6) | 0.0092 (11) | |
| O5 | 0.4326 (10) | 0.2381 (4) | 0.1156 (5) | 0.0085 (8) | |
| O6 | 0.6371 (8) | 0.2328 (5) | 0.9599 (5) | 0.0072 (11) | |
| O7 | 0.6926 (13) | 0.0084 (5) | 0.1529 (5) | 0.0111 (10) | |
| O8 | 0.0764 (12) | −0.0082 (5) | 0.3927 (5) | 0.0072 (9) | |
| O9 | 0.5643 (13) | 0.0063 (5) | 0.3906 (5) | 0.0069 (9) |
Atomic displacement parameters (Å2)
| U11 | U22 | U33 | U12 | U13 | U23 | |
| Al1 | 0.0071 (12) | 0.0044 (8) | 0.0067 (9) | 0.0012 (8) | 0.0032 (8) | 0.0005 (7) |
| Al2 | 0.0074 (12) | 0.0050 (8) | 0.0055 (8) | 0.0010 (8) | 0.0021 (8) | 0.0012 (7) |
| Lu1 | 0.00622 (14) | 0.00463 (12) | 0.00594 (10) | 0.00019 (12) | 0.00140 (14) | −0.00101 (8) |
| Lu2 | 0.00566 (13) | 0.00433 (12) | 0.00733 (10) | −0.00031 (13) | 0.00218 (14) | −0.00058 (8) |
| Lu3 | 0.00647 (13) | 0.00518 (11) | 0.00625 (10) | 0.00024 (13) | 0.00165 (13) | 0.00101 (9) |
| Lu4 | 0.00538 (14) | 0.00435 (10) | 0.00863 (10) | 0.00048 (13) | 0.00231 (15) | 0.00137 (9) |
| O1 | 0.008 (3) | 0.013 (3) | 0.008 (2) | 0.0039 (19) | 0.0002 (18) | 0.002 (2) |
| O2 | 0.009 (3) | 0.006 (2) | 0.007 (2) | 0.0012 (18) | 0.0030 (19) | 0.0010 (17) |
| O3 | 0.011 (3) | 0.006 (2) | 0.015 (2) | 0.000 (3) | 0.007 (3) | 0.0006 (17) |
| O4 | 0.009 (3) | 0.007 (2) | 0.009 (2) | 0.0039 (18) | −0.0009 (18) | −0.0003 (19) |
| O5 | 0.008 (2) | 0.0064 (18) | 0.012 (2) | −0.003 (2) | 0.004 (2) | −0.0003 (15) |
| O6 | 0.008 (3) | 0.007 (2) | 0.007 (2) | 0.0017 (18) | 0.0018 (18) | 0.0009 (17) |
| O7 | 0.013 (3) | 0.008 (2) | 0.016 (2) | 0.003 (3) | 0.009 (3) | 0.0059 (18) |
| O8 | 0.005 (3) | 0.006 (2) | 0.009 (2) | −0.003 (2) | 0.000 (3) | −0.0002 (16) |
| O9 | 0.010 (3) | 0.0042 (19) | 0.007 (2) | 0.001 (3) | 0.003 (3) | 0.0001 (16) |
Geometric parameters (Å, º)
| Al1—O3 | 1.724 (6) | Lu3—O5iv | 2.310 (5) |
| Al1—O4i | 1.733 (6) | Lu3—O6ii | 2.529 (5) |
| Al1—O5 | 1.754 (7) | Lu3—O4ii | 2.573 (6) |
| Al1—O2ii | 1.767 (6) | Lu3—Al2iv | 3.211 (2) |
| Al1—Lu1ii | 3.219 (2) | Lu3—Al1iv | 3.247 (2) |
| Al1—Lu3ii | 3.247 (2) | Lu3—Lu3iii | 3.4748 (8) |
| Al1—Lu3 | 3.336 (2) | Lu3—Lu4iii | 3.4803 (7) |
| Al2—O7 | 1.749 (6) | Lu4—O4ix | 2.198 (6) |
| Al2—O1ii | 1.753 (6) | Lu4—O9 | 2.253 (8) |
| Al2—O6i | 1.755 (6) | Lu4—O6ii | 2.255 (6) |
| Al2—O5 | 1.767 (7) | Lu4—O8v | 2.257 (8) |
| Al2—Lu3ii | 3.211 (2) | Lu4—O1ii | 2.287 (6) |
| Al2—Lu1ii | 3.272 (2) | Lu4—O8iii | 2.311 (5) |
| Al2—Lu4 | 3.285 (2) | Lu4—Lu3iii | 3.4804 (7) |
| Lu1—O9iii | 2.219 (5) | Lu4—Lu4x | 3.5061 (8) |
| Lu1—O6 | 2.233 (5) | Lu4—Lu2ix | 3.5641 (7) |
| Lu1—O3iii | 2.236 (8) | Lu4—Lu3v | 3.5652 (7) |
| Lu1—O7iii | 2.277 (8) | Lu4—Lu1ii | 3.5836 (7) |
| Lu1—O5iv | 2.344 (5) | O1—Al2iv | 1.753 (6) |
| Lu1—O2 | 2.461 (6) | O1—Lu2v | 2.172 (6) |
| Lu1—O1 | 2.524 (6) | O1—Lu4iv | 2.287 (6) |
| Lu1—Al1iv | 3.219 (2) | O2—Al1iv | 1.767 (6) |
| Lu1—Al2iv | 3.272 (2) | O2—Lu3iv | 2.238 (5) |
| Lu1—Lu2v | 3.5579 (7) | O3—Lu2vii | 2.213 (8) |
| Lu1—Lu4iv | 3.5836 (7) | O3—Lu1iii | 2.236 (8) |
| Lu1—Lu3 | 3.6270 (9) | O4—Al1xi | 1.733 (6) |
| Lu2—O1vi | 2.172 (6) | O4—Lu4viii | 2.198 (6) |
| Lu2—O3vii | 2.213 (8) | O4—Lu3iv | 2.573 (6) |
| Lu2—O2 | 2.235 (6) | O5—Lu3ii | 2.310 (5) |
| Lu2—O7iii | 2.263 (8) | O5—Lu1ii | 2.344 (5) |
| Lu2—O8vii | 2.280 (5) | O6—Al2xi | 1.754 (6) |
| Lu2—O4 | 2.337 (6) | O6—Lu4iv | 2.255 (6) |
| Lu2—Lu1vi | 3.5579 (7) | O6—Lu3iv | 2.529 (5) |
| Lu2—Lu4viii | 3.5641 (7) | O7—Lu2iii | 2.263 (8) |
| Lu2—Lu3iv | 3.6485 (7) | O7—Lu1iii | 2.277 (8) |
| Lu2—Lu4iii | 3.7187 (7) | O8—Lu4vi | 2.257 (8) |
| Lu2—Lu3vii | 3.9156 (7) | O8—Lu2vii | 2.280 (5) |
| Lu3—O2ii | 2.238 (5) | O8—Lu4iii | 2.311 (5) |
| Lu3—O9 | 2.242 (8) | O9—Lu1iii | 2.219 (5) |
| Lu3—O9iii | 2.260 (5) | O9—Lu3iii | 2.260 (5) |
| Lu3—O8 | 2.302 (7) | ||
| O3—Al1—O4i | 117.7 (3) | O2ii—Lu3—O8 | 96.84 (19) |
| O3—Al1—O5 | 116.2 (4) | O9—Lu3—O8 | 102.35 (18) |
| O4i—Al1—O5 | 94.7 (3) | O9iii—Lu3—O8 | 80.0 (2) |
| O3—Al1—O2ii | 109.3 (3) | O2ii—Lu3—O5iv | 106.69 (18) |
| O4i—Al1—O2ii | 121.3 (3) | O9—Lu3—O5iv | 120.4 (2) |
| O5—Al1—O2ii | 94.3 (3) | O9iii—Lu3—O5iv | 74.68 (16) |
| O3—Al1—Lu1ii | 128.9 (3) | O8—Lu3—O5iv | 123.6 (2) |
| O4i—Al1—Lu1ii | 111.6 (2) | O2ii—Lu3—O6ii | 78.65 (19) |
| O5—Al1—Lu1ii | 45.30 (17) | O9—Lu3—O6ii | 71.8 (2) |
| O2ii—Al1—Lu1ii | 49.24 (19) | O9iii—Lu3—O6ii | 104.6 (2) |
| O3—Al1—Lu3ii | 138.1 (3) | O8—Lu3—O6ii | 171.4 (2) |
| O4i—Al1—Lu3ii | 52.0 (2) | O5iv—Lu3—O6ii | 65.0 (2) |
| O5—Al1—Lu3ii | 43.34 (18) | O2ii—Lu3—O4ii | 74.48 (19) |
| O2ii—Al1—Lu3ii | 108.5 (2) | O9—Lu3—O4ii | 176.2 (2) |
| Lu1ii—Al1—Lu3ii | 68.24 (5) | O9iii—Lu3—O4ii | 103.8 (2) |
| O3—Al1—Lu3 | 72.9 (2) | O8—Lu3—O4ii | 75.8 (2) |
| O4i—Al1—Lu3 | 155.5 (2) | O5iv—Lu3—O4ii | 63.1 (2) |
| O5—Al1—Lu3 | 99.75 (19) | O6ii—Lu3—O4ii | 109.64 (15) |
| O2ii—Al1—Lu3 | 38.37 (18) | O2ii—Lu3—Al2iv | 96.50 (15) |
| Lu1ii—Al1—Lu3 | 67.47 (5) | O9—Lu3—Al2iv | 94.44 (18) |
| Lu3ii—Al1—Lu3 | 135.61 (8) | O9iii—Lu3—Al2iv | 86.21 (17) |
| O7—Al2—O1ii | 104.2 (3) | O8—Lu3—Al2iv | 155.68 (16) |
| O7—Al2—O6i | 124.1 (3) | O5iv—Lu3—Al2iv | 32.39 (17) |
| O1ii—Al2—O6i | 119.7 (3) | O6ii—Lu3—Al2iv | 32.95 (13) |
| O7—Al2—O5 | 115.6 (4) | O4ii—Lu3—Al2iv | 88.36 (14) |
| O1ii—Al2—O5 | 93.5 (3) | O2ii—Lu3—Al1iv | 93.90 (15) |
| O6i—Al2—O5 | 95.4 (3) | O9—Lu3—Al1iv | 151.60 (17) |
| O7—Al2—Lu3ii | 143.2 (3) | O9iii—Lu3—Al1iv | 85.82 (16) |
| O1ii—Al2—Lu3ii | 107.2 (2) | O8—Lu3—Al1iv | 98.38 (18) |
| O6i—Al2—Lu3ii | 51.62 (19) | O5iv—Lu3—Al1iv | 31.41 (17) |
| O5—Al2—Lu3ii | 44.47 (16) | O6ii—Lu3—Al1iv | 89.32 (13) |
| O7—Al2—Lu1ii | 123.1 (2) | O4ii—Lu3—Al1iv | 32.07 (14) |
| O1ii—Al2—Lu1ii | 49.8 (2) | Al2iv—Lu3—Al1iv | 60.46 (5) |
| O6i—Al2—Lu1ii | 111.7 (2) | O2ii—Lu3—Al1 | 29.36 (15) |
| O5—Al2—Lu1ii | 43.89 (17) | O9—Lu3—Al1 | 79.05 (14) |
| Lu3ii—Al2—Lu1ii | 68.03 (5) | O9iii—Lu3—Al1 | 149.97 (14) |
| O7—Al2—Lu4 | 65.8 (2) | O8—Lu3—Al1 | 85.02 (13) |
| O1ii—Al2—Lu4 | 41.4 (2) | O5iv—Lu3—Al1 | 134.72 (12) |
| O6i—Al2—Lu4 | 158.5 (2) | O6ii—Lu3—Al1 | 87.58 (13) |
| O5—Al2—Lu4 | 96.12 (18) | O4ii—Lu3—Al1 | 97.42 (14) |
| Lu3ii—Al2—Lu4 | 134.03 (8) | Al2iv—Lu3—Al1 | 115.70 (7) |
| Lu1ii—Al2—Lu4 | 66.26 (5) | Al1iv—Lu3—Al1 | 122.25 (5) |
| O9iii—Lu1—O6 | 174.8 (3) | O2ii—Lu3—Lu3iii | 142.19 (14) |
| O9iii—Lu1—O3iii | 86.4 (2) | O9—Lu3—Lu3iii | 39.67 (13) |
| O6—Lu1—O3iii | 89.4 (2) | O9iii—Lu3—Lu3iii | 39.30 (19) |
| O9iii—Lu1—O7iii | 85.8 (2) | O8—Lu3—Lu3iii | 91.43 (16) |
| O6—Lu1—O7iii | 98.0 (2) | O5iv—Lu3—Lu3iii | 98.91 (14) |
| O3iii—Lu1—O7iii | 101.03 (18) | O6ii—Lu3—Lu3iii | 87.86 (13) |
| O9iii—Lu1—O5iv | 74.76 (17) | O4ii—Lu3—Lu3iii | 143.06 (13) |
| O6—Lu1—O5iv | 105.69 (19) | Al2iv—Lu3—Lu3iii | 90.40 (5) |
| O3iii—Lu1—O5iv | 128.4 (2) | Al1iv—Lu3—Lu3iii | 121.35 (4) |
| O7iii—Lu1—O5iv | 124.3 (2) | Al1—Lu3—Lu3iii | 116.13 (4) |
| O9iii—Lu1—O2 | 104.5 (2) | O2ii—Lu3—Lu4iii | 137.27 (15) |
| O6—Lu1—O2 | 80.21 (19) | O9—Lu3—Lu4iii | 95.71 (15) |
| O3iii—Lu1—O2 | 165.4 (2) | O9iii—Lu3—Lu4iii | 39.5 (2) |
| O7iii—Lu1—O2 | 70.7 (2) | O8—Lu3—Lu4iii | 41.12 (12) |
| O5iv—Lu1—O2 | 64.9 (2) | O5iv—Lu3—Lu4iii | 96.21 (14) |
| O9iii—Lu1—O1 | 100.2 (2) | O6ii—Lu3—Lu4iii | 144.07 (12) |
| O6—Lu1—O1 | 75.68 (19) | O4ii—Lu3—Lu4iii | 85.06 (13) |
| O3iii—Lu1—O1 | 73.7 (2) | Al2iv—Lu3—Lu4iii | 120.37 (4) |
| O7iii—Lu1—O1 | 171.6 (2) | Al1iv—Lu3—Lu4iii | 87.25 (5) |
| O5iv—Lu1—O1 | 63.4 (2) | Al1—Lu3—Lu4iii | 123.92 (4) |
| O2—Lu1—O1 | 112.92 (16) | Lu3iii—Lu3—Lu4iii | 64.036 (14) |
| O9iii—Lu1—Al1iv | 87.18 (17) | O4ix—Lu4—O9 | 163.0 (2) |
| O6—Lu1—Al1iv | 95.83 (15) | O4ix—Lu4—O6ii | 87.53 (18) |
| O3iii—Lu1—Al1iv | 160.44 (18) | O9—Lu4—O6ii | 77.1 (2) |
| O7iii—Lu1—Al1iv | 96.91 (18) | O4ix—Lu4—O8v | 84.7 (2) |
| O5iv—Lu1—Al1iv | 32.14 (17) | O9—Lu4—O8v | 110.30 (17) |
| O2—Lu1—Al1iv | 32.95 (13) | O6ii—Lu4—O8v | 171.9 (2) |
| O1—Lu1—Al1iv | 89.26 (14) | O4ix—Lu4—O1ii | 75.4 (2) |
| O9iii—Lu1—Al2iv | 85.38 (16) | O9—Lu4—O1ii | 108.45 (19) |
| O6—Lu1—Al2iv | 92.47 (15) | O6ii—Lu4—O1ii | 80.3 (2) |
| O3iii—Lu1—Al2iv | 100.91 (19) | O8v—Lu4—O1ii | 100.0 (2) |
| O7iii—Lu1—Al2iv | 155.76 (18) | O4ix—Lu4—O8iii | 95.5 (2) |
| O5iv—Lu1—Al2iv | 31.50 (17) | O9—Lu4—O8iii | 79.9 (2) |
| O2—Lu1—Al2iv | 89.77 (14) | O6ii—Lu4—O8iii | 98.7 (2) |
| O1—Lu1—Al2iv | 32.02 (14) | O8v—Lu4—O8iii | 79.7 (3) |
| Al1iv—Lu1—Al2iv | 60.13 (5) | O1ii—Lu4—O8iii | 170.9 (2) |
| O9iii—Lu1—Lu2v | 91.9 (2) | O4ix—Lu4—Al2 | 104.05 (15) |
| O6—Lu1—Lu2v | 82.89 (14) | O9—Lu4—Al2 | 83.86 (13) |
| O3iii—Lu1—Lu2v | 36.67 (18) | O6ii—Lu4—Al2 | 91.72 (14) |
| O7iii—Lu1—Lu2v | 137.63 (18) | O8v—Lu4—Al2 | 92.45 (14) |
| O5iv—Lu1—Lu2v | 95.47 (17) | O1ii—Lu4—Al2 | 30.48 (15) |
| O2—Lu1—Lu2v | 149.10 (13) | O8iii—Lu4—Al2 | 158.20 (14) |
| O1—Lu1—Lu2v | 37.17 (13) | O4ix—Lu4—Lu3iii | 135.90 (15) |
| Al1iv—Lu1—Lu2v | 125.28 (5) | O9—Lu4—Lu3iii | 39.61 (13) |
| Al2iv—Lu1—Lu2v | 65.26 (5) | O6ii—Lu4—Lu3iii | 92.25 (14) |
| O9iii—Lu1—Lu4iv | 139.2 (2) | O8v—Lu4—Lu3iii | 91.67 (16) |
| O6—Lu1—Lu4iv | 37.22 (14) | O1ii—Lu4—Lu3iii | 147.82 (15) |
| O3iii—Lu1—Lu4iv | 85.85 (17) | O8iii—Lu4—Lu3iii | 40.93 (18) |
| O7iii—Lu1—Lu4iv | 135.01 (15) | Al2—Lu4—Lu3iii | 120.03 (4) |
| O5iv—Lu1—Lu4iv | 79.07 (14) | O4ix—Lu4—Lu4x | 90.25 (15) |
| O2—Lu1—Lu4iv | 91.80 (13) | O9—Lu4—Lu4x | 96.21 (15) |
| O1—Lu1—Lu4iv | 39.37 (13) | O6ii—Lu4—Lu4x | 137.47 (14) |
| Al1iv—Lu1—Lu4iv | 86.95 (5) | O8v—Lu4—Lu4x | 40.44 (13) |
| Al2iv—Lu1—Lu4iv | 57.05 (4) | O1ii—Lu4—Lu4x | 139.71 (15) |
| Lu2v—Lu1—Lu4iv | 59.875 (14) | O8iii—Lu4—Lu4x | 39.3 (2) |
| O9iii—Lu1—Lu3 | 36.30 (13) | Al2—Lu4—Lu4x | 129.75 (4) |
| O6—Lu1—Lu3 | 143.97 (15) | Lu3iii—Lu4—Lu4x | 61.365 (15) |
| O3iii—Lu1—Lu3 | 110.32 (15) | O4ix—Lu4—Lu2ix | 39.59 (15) |
| O7iii—Lu1—Lu3 | 106.94 (16) | O9—Lu4—Lu2ix | 142.06 (14) |
| O5iv—Lu1—Lu3 | 38.47 (12) | O6ii—Lu4—Lu2ix | 82.47 (14) |
| O2—Lu1—Lu3 | 83.91 (13) | O8v—Lu4—Lu2ix | 93.01 (16) |
| O1—Lu1—Lu3 | 81.20 (13) | O1ii—Lu4—Lu2ix | 35.84 (15) |
| Al1iv—Lu1—Lu3 | 56.26 (4) | O8iii—Lu4—Lu2ix | 135.12 (17) |
| Al2iv—Lu1—Lu3 | 55.19 (4) | Al2—Lu4—Lu2ix | 65.06 (4) |
| Lu2v—Lu1—Lu3 | 95.095 (18) | Lu3iii—Lu4—Lu2ix | 172.933 (13) |
| Lu4iv—Lu1—Lu3 | 112.083 (15) | Lu4x—Lu4—Lu2ix | 120.06 (2) |
| O1vi—Lu2—O3vii | 81.6 (2) | O4ix—Lu4—Lu3v | 45.83 (16) |
| O1vi—Lu2—O2 | 89.32 (19) | O9—Lu4—Lu3v | 149.15 (16) |
| O3vii—Lu2—O2 | 169.1 (2) | O6ii—Lu4—Lu3v | 133.35 (14) |
| O1vi—Lu2—O7iii | 164.5 (2) | O8v—Lu4—Lu3v | 39.02 (17) |
| O3vii—Lu2—O7iii | 113.97 (17) | O1ii—Lu4—Lu3v | 85.63 (15) |
| O2—Lu2—O7iii | 75.2 (2) | O8iii—Lu4—Lu3v | 88.7 (2) |
| O1vi—Lu2—O8vii | 91.6 (2) | Al2—Lu4—Lu3v | 98.07 (5) |
| O3vii—Lu2—O8vii | 88.2 (2) | Lu3iii—Lu4—Lu3v | 120.326 (15) |
| O2—Lu2—O8vii | 98.0 (2) | Lu4x—Lu4—Lu3v | 58.961 (16) |
| O7iii—Lu2—O8vii | 89.1 (3) | Lu2ix—Lu4—Lu3v | 61.562 (13) |
| O1vi—Lu2—O4 | 74.9 (2) | O4ix—Lu4—Lu1ii | 86.32 (15) |
| O3vii—Lu2—O4 | 92.4 (2) | O9—Lu4—Lu1ii | 85.60 (15) |
| O2—Lu2—O4 | 79.5 (2) | O6ii—Lu4—Lu1ii | 36.81 (14) |
| O7iii—Lu2—O4 | 103.2 (2) | O8v—Lu4—Lu1ii | 144.42 (14) |
| O8vii—Lu2—O4 | 166.2 (2) | O1ii—Lu4—Lu1ii | 44.44 (15) |
| O1vi—Lu2—Lu1vi | 44.59 (16) | O8iii—Lu4—Lu1ii | 135.46 (19) |
| O3vii—Lu2—Lu1vi | 37.11 (17) | Al2—Lu4—Lu1ii | 56.69 (4) |
| O2—Lu2—Lu1vi | 133.86 (14) | Lu3iii—Lu4—Lu1ii | 117.97 (2) |
| O7iii—Lu2—Lu1vi | 150.92 (17) | Lu4x—Lu4—Lu1ii | 173.404 (16) |
| O8vii—Lu2—Lu1vi | 87.2 (2) | Lu2ix—Lu4—Lu1ii | 59.705 (14) |
| O4—Lu2—Lu1vi | 84.98 (14) | Lu3v—Lu4—Lu1ii | 121.266 (15) |
| O1vi—Lu2—Lu4viii | 38.06 (15) | Al2iv—O1—Lu2v | 139.9 (3) |
| O3vii—Lu2—Lu4viii | 86.66 (16) | Al2iv—O1—Lu4iv | 108.1 (3) |
| O2—Lu2—Lu4viii | 82.52 (14) | Lu2v—O1—Lu4iv | 106.1 (2) |
| O7iii—Lu2—Lu4viii | 137.89 (15) | Al2iv—O1—Lu1 | 98.2 (3) |
| O8vii—Lu2—Lu4viii | 129.58 (17) | Lu2v—O1—Lu1 | 98.2 (2) |
| O4—Lu2—Lu4viii | 36.84 (14) | Lu4iv—O1—Lu1 | 96.2 (2) |
| Lu1vi—Lu2—Lu4viii | 60.420 (13) | Al1iv—O2—Lu2 | 127.6 (3) |
| O1vi—Lu2—Lu3iv | 85.18 (17) | Al1iv—O2—Lu3iv | 112.3 (3) |
| O3vii—Lu2—Lu3iv | 136.93 (14) | Lu2—O2—Lu3iv | 109.3 (2) |
| O2—Lu2—Lu3iv | 35.36 (14) | Al1iv—O2—Lu1 | 97.8 (2) |
| O7iii—Lu2—Lu3iv | 83.02 (17) | Lu2—O2—Lu1 | 103.7 (2) |
| O8vii—Lu2—Lu3iv | 133.14 (18) | Lu3iv—O2—Lu1 | 101.5 (2) |
| O4—Lu2—Lu3iv | 44.56 (15) | Al1—O3—Lu2vii | 126.3 (5) |
| Lu1vi—Lu2—Lu3iv | 119.653 (15) | Al1—O3—Lu1iii | 123.9 (5) |
| Lu4viii—Lu2—Lu3iv | 59.233 (14) | Lu2vii—O3—Lu1iii | 106.2 (2) |
| O1vi—Lu2—Lu1 | 128.85 (16) | Al1xi—O4—Lu4viii | 135.4 (3) |
| O3vii—Lu2—Lu1 | 149.48 (17) | Al1xi—O4—Lu2 | 117.6 (3) |
| O2—Lu2—Lu1 | 40.30 (14) | Lu4viii—O4—Lu2 | 103.6 (2) |
| O7iii—Lu2—Lu1 | 35.63 (17) | Al1xi—O4—Lu3iv | 95.9 (3) |
| O8vii—Lu2—Lu1 | 88.6 (2) | Lu4viii—O4—Lu3iv | 96.4 (2) |
| O4—Lu2—Lu1 | 97.74 (14) | Lu2—O4—Lu3iv | 95.9 (2) |
| Lu1vi—Lu2—Lu1 | 172.025 (12) | Al1—O5—Al2 | 134.9 (3) |
| Lu4viii—Lu2—Lu1 | 118.072 (14) | Al1—O5—Lu3ii | 105.3 (3) |
| Lu3iv—Lu2—Lu1 | 59.438 (13) | Al2—O5—Lu3ii | 103.1 (3) |
| O1vi—Lu2—Lu4iii | 124.70 (15) | Al1—O5—Lu1ii | 102.6 (3) |
| O3vii—Lu2—Lu4iii | 102.42 (15) | Al2—O5—Lu1ii | 104.6 (3) |
| O2—Lu2—Lu4iii | 87.60 (14) | Lu3ii—O5—Lu1ii | 102.39 (18) |
| O7iii—Lu2—Lu4iii | 54.38 (15) | Al2xi—O6—Lu1 | 122.0 (3) |
| O8vii—Lu2—Lu4iii | 34.8 (2) | Al2xi—O6—Lu4iv | 125.6 (3) |
| O4—Lu2—Lu4iii | 156.67 (14) | Lu1—O6—Lu4iv | 106.0 (2) |
| Lu1vi—Lu2—Lu4iii | 117.607 (14) | Al2xi—O6—Lu3iv | 95.4 (2) |
| Lu4viii—Lu2—Lu4iii | 159.792 (10) | Lu1—O6—Lu3iv | 99.6 (2) |
| Lu3iv—Lu2—Lu4iii | 118.642 (17) | Lu4iv—O6—Lu3iv | 100.7 (2) |
| Lu1—Lu2—Lu4iii | 60.716 (12) | Al2—O7—Lu2iii | 126.1 (5) |
| O1vi—Lu2—Lu3vii | 85.85 (16) | Al2—O7—Lu1iii | 123.6 (5) |
| O3vii—Lu2—Lu3vii | 56.75 (14) | Lu2iii—O7—Lu1iii | 109.0 (2) |
| O2—Lu2—Lu3vii | 128.77 (14) | Lu4vi—O8—Lu2vii | 110.1 (3) |
| O7iii—Lu2—Lu3vii | 102.54 (16) | Lu4vi—O8—Lu3 | 102.9 (2) |
| O8vii—Lu2—Lu3vii | 31.5 (2) | Lu2vii—O8—Lu3 | 117.4 (3) |
| O4—Lu2—Lu3vii | 146.03 (14) | Lu4vi—O8—Lu4iii | 100.3 (3) |
| Lu1vi—Lu2—Lu3vii | 62.045 (13) | Lu2vii—O8—Lu4iii | 125.0 (2) |
| Lu4viii—Lu2—Lu3vii | 119.182 (17) | Lu3—O8—Lu4iii | 97.9 (2) |
| Lu3iv—Lu2—Lu3vii | 161.782 (11) | Lu1iii—O9—Lu3 | 120.0 (4) |
| Lu1—Lu2—Lu3vii | 116.038 (15) | Lu1iii—O9—Lu4 | 113.8 (3) |
| Lu4iii—Lu2—Lu3vii | 55.607 (13) | Lu3—O9—Lu4 | 110.2 (2) |
| O2ii—Lu3—O9 | 102.6 (2) | Lu1iii—O9—Lu3iii | 108.2 (2) |
| O2ii—Lu3—O9iii | 176.7 (3) | Lu3—O9—Lu3iii | 101.0 (3) |
| O9—Lu3—O9iii | 79.0 (3) | Lu4—O9—Lu3iii | 100.9 (3) |
Symmetry codes: (i) x, y, z−1; (ii) x, −y+1/2, z−1/2; (iii) −x+1, −y, −z+1; (iv) x, −y+1/2, z+1/2; (v) x+1, y, z; (vi) x−1, y, z; (vii) −x, −y, −z+1; (viii) x−1, −y+1/2, z+1/2; (ix) x+1, −y+1/2, z−1/2; (x) −x+2, −y, −z+1; (xi) x, y, z+1.
Funding Statement
This work was funded by Mitsubishi Chemical Group Science and Technology Research Center, Inc. grant J180002907.
References
- Brandle, C. D. & Steinfink, H. (1969). Inorg. Chem. 8, 1320–1324.
- Brown, I. D. & Altermatt, D. (1985). Acta Cryst. B41, 244–247.
- Bruker (2016). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.
- Bruker (2017). SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.
- Bruker (2018). APEX3 . Bruker AXS Inc., Madison, Wisconsin, USA.
- Christensen, A. N. & Hazell, R. G. (1991). Acta Chem. Scand. 45, 226–230.
- Dernier, P. D. & Maines, R. G. (1971). Mater. Res. Bull. 6, 433–439.
- Ding, L., Zhang, Q., Luo, J., Liu, W., Zhou, W. & Yin, S. (2011). J. Alloys Compd. 509, 10167–10171.
- Dohrup, J., Hoyvald, A., Mogensen, G., Jacobsen, C. J. H. & Villadsen, J. (1996). J. Am. Ceram. Soc. 79, 2959–2960.
- Drozdowski, W., Lukasiewicz, T., Wojtowicz, A. J., Wisniewski, D. & Kisielewski, J. (2005). J. Cryst. Growth, 275, e709–e714.
- Euler, F. & Bruce, J. A. (1965). Acta Cryst. 19, 971–978.
- Gagné, O. C. & Hawthorne, F. C. (2015). Acta Cryst. B71, 562–578. [DOI] [PMC free article] [PubMed]
- Jero, P. D. & Kriven, W. M. (1988). J. Am. Ceram. Soc. 71, C454–C455.
- Klimm, D. (2010). J. Cryst. Growth, 312, 730–733.
- Lehmann, M. S., Christensen, A. N., Fjellvåg, H., Feidenhans’l, R. & Nielsen, M. (1987). J. Appl. Cryst. 20, 123–129.
- Lempicki, A., Brecher, C., Wisniewski, D., Zych, E. & Wojtowicz, A. J. (1996). IEEE Trans. Nucl. Sci. 43, 1316–1320.
- Li, Y. Q., Hirosaki, N., Xie, R. J., Takeda, T., Lofland, S. E. & Ramanujachary, K. V. (2009). J. Alloys Compd. 484, 943–948.
- Martín-Sedeño, M. C., Marrero-López, D., Losilla, E. R., Bruque, S., Núñez, P. & Aranda, M. A. G. (2006). J. Solid State Chem. 179, 3445–3455.
- Mizuno, M. (1979). J. Ceram. Soc. Jpn, 87, 405–412.
- Mizuno, M. & Noguchi, T. (1980). J. Ceram. Soc. Jpn, 88, 322–327.
- Mizuno, M., Yamada, T. & Noguchi, T. (1977a). J. Ceram. Soc. Jpn, 85, 374–379.
- Mizuno, M., Yamada, T. & Noguchi, T. (1977b). J. Ceram. Soc. Jpn, 85, 543–548.
- Mizuno, M., Yamada, T. & Noguchi, T. (1978). J. Ceram. Soc. Jpn, 86, 359–364.
- Momma, K. & Izumi, F. (2011). J. Appl. Cryst. 44, 1272–1276.
- Nikl, M. (2000). Phys. Status Solidi A, 178, 595-620.
- Nikl, M., Yoshikawa, A., Kamada, K., Nejezchleb, K., Stanek, C. R., Mares, J. A. & Blazek, K. (2013). Prog. Cryst. Growth Charact. Mater. 59, 47–72.
- Petrosyan, A. G., Popova, V. F., Gusarov, V. V., Shirinyan, G. O., Pedrini, C. & Lecoq, P. (2006). J. Cryst. Growth, 293, 74–77.
- Petrosyan, A. G., Popova, V. F., Ugolkov, V. L., Romanov, D. P. & Ovanesyan, K. L. (2013). J. Cryst. Growth, 377, 178–183.
- Reed, J. W. & Chase, A. B. (1962). Acta Cryst. 15, 812.
- Shannon, R. D. (1976). Acta Cryst. A32, 751–767.
- Sheldrick, G. M. (2015). Acta Cryst. C71, 3–8.
- Shirvinskaya, A. K. & Popova, V. F. (1977). Dokl. Akad. Nauk SSSR, 233, 1110–1113.
- Shishido, T., Nojima, S., Tanaka, M., Horiuchi, H. & Fukuda, T. (1995). J. Alloys Compd. 227, 175–179.
- Talik, E., Guzik, A., Zajdel, P., Lipifska, L., Baran, M. & Szubka, M. (2016). Mater. Res. Bull. 83, 56–64.
- Wang, Z., Zou, J., Zhang, C., Yang, B., Shi, M., Li, Y., Zhou, H., Liu, Y., Li, M. & Liu, Z. (2018). J. Non-Cryst. Solids, 489, 57–63.
- Warshaw, I. & Roy, R. (1959). J. Am. Ceram. Soc. 42, 434–438.
- Westrip, S. P. (2010). J. Appl. Cryst. 43, 920–925.
- Wojtowicz, A. J. (1999). Acta Phys. Pol. A, 95, 165–178.
- Wojtowicz, A. J., Drozdowski, W., Wisniewski, D., Lefaucheur, J.-L., Galazka, Z., Gou, Z., Lukasiewicz, T. & Kisielewski, J. (2006). Opt. Mater. 28, 85–93.
- Wu, P. & Pelton, A. D. (1992). J. Alloys Compd. 179, 259–287.
- Xiang, R., Liang, X., Li, P., Di, X. & Xiang, W. (2016). Chem. Eng. J. 306, 858–865.
- Yamane, H., Ogawara, K., Omori, M. & Hirai, T. (1995a). J. Am. Ceram. Soc. 78, 2385–2390.
- Yamane, H., Omori, M. & Hirai, T. (1995b). J. Mater. Sci. Lett. 14, 561–563.
- Zhang, L., Madej, C., Pedrini, C., Dujardin, C., Kamenskikh, I., Belsky, A., Shaw, D. A., Mesnard, P. & Fouassier, C. (1998). J. Electrochem. Soc.: Proceedings of the Sixth International Conference on Luminescent materials 97, 342-351.
- Zhang, L., Madej, C., Pédrini, C., Moine, B., Dujardin, C., Petrosyan, A. & Belsky, A. N. (1997). Chem. Phys. Lett. 268, 408–412.
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Crystal structure: contains datablock(s) I. DOI: 10.1107/S2056989020005757/cq2036sup1.cif
Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989020005757/cq2036Isup2.hkl
Figure S1. Powder XRD patterns of samples prepared (a) under air and (b) under Ar. DOI: 10.1107/S2056989020005757/cq2036sup3.tif
CCDC reference: 1999289
Additional supporting information: crystallographic information; 3D view; checkCIF report



