Literature DB >> 27555963

Crystal structure of Cr-bearing Mg3BeAl8O16, a new polytype of magnesiotaaffeite-2N'2S.

Thomas Malcherek1, Jochen Schlüter2.   

Abstract

The crystal structure of a new polytype of magnesiotaaffeite-2N'2S, ideally Mg3BeAl8O16 (trimagnesium beryllium octa-aluminium hexa-deca-oxide), is described in space-group symmetry P-3m1. It has been identified in a fragment of a mineral sample from Burma (Myanmar). The new polytype is composed of two Mg2Al4O8 (S)- and two BeMgAl4O8 (N')-modules in a stacking sequence N'SSN'' which differs from the N'SN'S-stacking sequence of the known magnesiotaaffeite-2N'2S polytype. The crystal structure can be derived from a close-packed arrangement of O atoms and is discussed with regard to its polytypism and its Cr(3+) chromophore content.

Entities:  

Keywords:  crystal structure; gemstones; magnesiotaaffeite; modular structure; polysomatism; polytypism

Year:  2016        PMID： 27555963      PMCID： PMC4992938          DOI： 10.1107/S2056989016010215

Source DB:  PubMed          Journal:  Acta Crystallogr E Crystallogr Commun


Mineralogical and crystal-chemical context

The minerals of the taaffeite group form a polysomatic series, composed of spinel (S) and nolanite (N′) modules (Armbruster, 2002 ▸). The nolanite modules in the taaffeites are modified with respect to the nolanite, (V,Fe)5O7(OH), crystal structure (Gatehouse et al., 1983 ▸), such that Be nominally substitutes for the hydrogen atoms of the nolanite OH group, while Mg and Al replace V and Fe, respectively. Variable numbers of the S-modules, Mg2Al4O8, and of the N′-modules, BeMgAl4O8, combine to yield different compositions of taaffeite minerals, i.e. different polysomes. Magnesiotaaffeite-2N′2S is composed of two modified nolanite modules N′ and two spinel modules S, yielding an idealized composition of Mg3BeAl8O16. Be-doping of MgAl2O4 has been shown to cause growth of twinned spinel crystals as a precursor to the formation of magnesiotaaffeite polytypes (Drev et al., 2013 ▸). Here we report the crystal structure of a new polytype of magnesiotaaffeite, magnesiotaaffeite-2N′2S 2 which differs from the known magnesiotaaffeite-2N′2S (Nuber & Schmetzer, 1983 ▸) by the module stacking sequence. The resulting space group symmetry is P-3m1, as opposed to the P63 mc symmetry of the previously known polytype.

Structural commentary

The crystal structure of the title compound is shown in Fig. 1 ▸. It can be described by the stacking of close-packed oxygen layers along [001], with layers of cations filling the inter­stices. Following the layer nomenclature of Nuber & Schmetzer (1983 ▸), the [6]Al1, [6]Al3 and [6]Al4 cations can be attributed to O-layers, the [6]Al5, [4]Mg1 and [4]Mg2 cations to T 2-layers and the [4]Be,[4]Al2 and [6]Mg3 cations to T 1-layers. The cation stacking sequence is then T 1-O-T 2-O-T 2-O-T 1′-⋯ while the anion stacking sequence is BACBACBC⋯. The orientation of T 1′ is upside down with respect to T 1. In the polytype described by Nuber & Schmetzer (1983 ▸), the stacking sequence is T 1-O-T 2-O-T 1-O-T 2-O-⋯ and BCABCBAC⋯ by comparison. In terms of polysomatism, the N′ layer is composed of one T 1 and one O-layer. The second nolanite layer, N′′, is also composed of these layer types, but its T 1 layer is inverted with respect to the stacking direction. The S-layer is composed of one O-layer and one T 2-layer. Stacking these modules in the order N′-S-S-N′′-N′-⋯ generates the new polytype structure (Fig. 1 ▸). The stacking sequence of the known magnesiotaaffeite-2N′2S polytype is N′-S-N′-S- ⋯.
Figure 1

Polyhedral plot of magnesiotaaffeite-2N′2S 2 viewed down [010] with cation site nomenclature and coordination numbers given to the right. Module sequence is N′–S–S–N′′–N′ from bottom to top, with boundaries indicated by horizontal lines. Displacement ellipsoids are drawn at the 99% probability level. Mg atoms are shown in yellow, Al in blue, Be in green and O in red.

The composition obtained by structure refinement is in good agreement with the composition obtained by electron microprobe analysis (EMPA). The calculated bond-valence sums agree reasonably well with the formal charges (Table 1 ▸), and on average they support the assumption that Cr is trivalent. Significant amounts of Cr3+ are found at the octa­hedrally coordinated Al3 and Al4-sites, where Cr3+ is overbonded, as well as at the tetra­hedrally coordinated Mg1 and Mg2 sites, where Cr3+ is underbonded. Cr3+ in tetra­hedral coordination is unusual, but has recently been reported for the brownmiller­ite-type compound Ca2Cr2O5 (Arevalo-Lopez & Attfield, 2015 ▸) and for Cr-doped BaAl2O4 (Vrankić et al., 2015 ▸). However, without further confirmation by other methods, the appearance of tetra­hedrally coordinated Cr3+ in the title compound should be treated with caution. The tetra­hedral Mg1 coordination, with one Mg1—O6 distance of 1.9537 (12) Å and three Mg1—O4 distances of 1.9296 (7) Å is more distorted than the Mg2 coordination environment, where the longer Mg2—O1 distance [1.9361 (13) Å] hardly differs from the three 1.9300 (7) Å Mg2—O5 distances. The average bond lengths at the tetra­hedral sites, nominally occupied by Mg (Mg1 1.936 Å, Mg2 1.932 Å), and at the octa­hedral sites, nominally occupied by Al (Al1 1.909 Å, Al3 1.916 Å, Al4 1.913 Å, Al5 1.909 Å), are similar to the T-O (1.936 Å) and M-O (1.923 Å) distances reported for a natural Cr and V-bearing spinel from Burma with a small inversion parameter (Widmer et al., 2015 ▸). This indicates that the degree of Mg, Al disorder is equally low in the title compound. The Al2 site is at the center of a nearly regular oxygen tetra­hedron with an average Al—O distance of 1.785 Å. Al3+ is slightly underbonded at this site (Table 1 ▸), which might indicate admixture of Mg atoms. The slightly overbonded Mg2 site might accommodate the resulting Al-excess. The Be2+ cation forms one short bond with O7 [1.602 (2) Å] and three longer bonds [1.6615 (13) Å] with the O3-anions, while the tetra­hedral angles are either 97.89 (9)° (O3—Be1—O3) or 119.45 (7)° (O7—Be1—O3). The Mg atom in the Mg3O6-octa­hedron exhibits a strong out-of-centre distortion, away from the Al3-cation, to which it has a distance of only 3.0580 (7) Å.
Table 1

Bond-valence sums (BVS)

Calculated using JANA2006 (Petřìček et al., 2014 ▸) with bond-valence parameters taken from Brese & O’Keeffe (1991 ▸). Angular brackets indicate site-occupancy weighted averages for the corresponding Mab sites.

SiteBVS
Be11.956 (5)
Al13.007 (2)
Al22.788 (3)
Al3a 2.932 (2)
Cr3b 3.571 (3)
<M3ab>2.943
Al4a 2.955 (2)
Cr4b 3.599 (3)
<M4ab>2.966
Al52.991 (2)
Mg1a 2.077 (2)
Cr1b 2.259 (2)
<M1ab>2.082
Mg2a 2.099 (3)
Cr2b 2.283 (3)
<M2ab>2.108
Mg31.974 (2)
O12.006 (2)
O21.991 (3)
O31.962 (2)
O42.009 (2)
O52.008 (2)
O62.045 (2)
O71.993 (4)
O81.906 (2)
Rotation of the refined crystal structure by 60° about [001] brings the bottom O-layer (Fig. 1 ▸) into the same orientation as the third O-layer of the unrotated structure. Thus a corres­pondingly rotated twin domain of the polytype structure can form a strain free boundary after the first S-layer of the module sequence as shown in Fig. 1 ▸. At the twin boundary this results in a module sequence N′-S-N′-S, corresponding to the previously described polytype.

Sample details and EMPA

The studied natural sample of magnesiotaaffeite (m = 0.95 g) originates from Chaung-gyi, Mogok, Pyin-Oo-Lwin district, Burma (Myanmar). It has a red colour and a layered appearance (Fig. 2 ▸). A small fragment of the original sample was examined using single crystal X-ray diffraction. The same crystal fragment was subsequently prepared for electron microprobe analysis (EMPA) using a Cameca SX100 electron microprobe, operating in wavelength-dispersion mode at 15 kV and 20 nA. Standards were MgO, Al2O3 and Cr2O3. Based on 16 anions and the Be concentration from single-crystal X-ray structure refinement (1 Be), the empirical chemical formula was determined as Al7.86Be1.0Cr0.19Mg2.93O16. The corresponding oxide composition (in wt%) is MgO 20.82, Cr2O3 2.50, Al2O3 70.72, BeO 4.41, yielding a total of 98.45%.
Figure 2

Magnesiotaaffeite sample, approximate size 1.0 × 0.9 × 0.8 cm. (Photograph courtesy of Daniela Braith, Munich.)

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2 ▸. The results of the EMPA indicate that the magnesiotaaffeite crystal contains significant amounts of Cr. In order to accurately refine small Cr-site populations against the major constituent elements Al and Mg, intensities at small scattering angles were systematically weighted down by a factor of 1−exp[−5(sin θ/λ)2] in order to emphasize core electron contributions to the X-ray scattering. For that purpose, Cr and Mg or Al were constrained to have the same coordinates and displacement parameters under consideration of full occupancy for the corresponding site. Scattering factors for neutral atoms were used and all atoms were refined with anisotropic displacement parameters. No evidence for mixed occupancy was found at the Be site; small Cr amounts were found for the Al3, Al4, Mg1 and Mg2 sites with occupation factors for Cr of 0.017 (3), 0.017 (5), 0.028 (5) and 0.048 (5), respectively. Two twin domains (twinning by merohedry) with volume fractions of 0.64 and 0.36 contribute to the total scattering intensity, related by reflection parallel to [10] or, equivalently, by 60° rotation about [001].
Table 2

Experimental details

Crystal data
Chemical formulaMg3BeAl8O16
M r 557.75
Crystal system, space groupTrigonal, P m1
Temperature (K)295
a, c (Å)5.6788 (3), 18.3368 (14)
V (Å3)512.11 (7)
Z 2
Radiation typeMo Kα
μ (mm−1)1.25
Crystal size (mm)0.23 × 0.22 × 0.10
 
Data collection
DiffractometerNonius KappaCCD
Absorption correctionMulti-scan (SADABS; Bruker, 2008 ▸)
T min, T max 0.614, 0.747
No. of measured, independent and observed [I > 2σ(I)] reflections10618, 940, 912
R int 0.040
(sin θ/λ)max (Å−1)0.807
 
Refinement
R[F 2 > 2σ(F 2)], wR(F 2), S 0.018, 0.040, 0.83
No. of reflections940
No. of parameters75
Δρmax, Δρmin (e Å−3)0.41, −1.01

Computer programs: COLLECT (Nonius, 1998 ▸), EVAL15/Peakref and EVAL15 (Schreurs et al., 2010 ▸), SUPERFLIP (Palatinus & Chapuis, 2007 ▸), SHELXL2014 (Sheldrick, 2015 ▸), VESTA (Momma & Izumi, 2011 ▸) and publCIF (Westrip, 2010 ▸).

Crystal structure: contains datablock(s) I. DOI: 10.1107/S2056989016010215/wm5296sup1.cif Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989016010215/wm5296Isup2.hkl CCDC reference: 1487140 Additional supporting information: crystallographic information; 3D view; checkCIF report
Mg3BeAl8O16Dx = 3.617 Mg m−3
Mr = 557.75Mo Kα radiation, λ = 0.71069 Å
Trigonal, P3m1Cell parameters from 9717 reflections
a = 5.6788 (3) Åθ = 2.2–35°
c = 18.3368 (14) ŵ = 1.25 mm−1
V = 512.11 (7) Å3T = 295 K
Z = 2Tabular, red
F(000) = 5470.23 × 0.22 × 0.10 mm
Nonius KappaCCD diffractometer940 independent reflections
Radiation source: fine-focus sealed X-ray tube912 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.040
Detector resolution: 9 pixels mm-1θmax = 35.0°, θmin = 2.2°
φ scans, and ω scans with κ offsetsh = −8→9
Absorption correction: multi-scan (SADABS; Bruker, 2008)k = −9→8
Tmin = 0.614, Tmax = 0.747l = −29→29
10618 measured reflections
Refinement on F20 restraints
Least-squares matrix: fullw = {1-exp[-5(sinθ/λ)2)]}/[σ2(Fo2) + (0.0296P)2 + 0.031P] where P = (Fo2 + 2Fc2)/3
R[F2 > 2σ(F2)] = 0.018(Δ/σ)max < 0.001
wR(F2) = 0.040Δρmax = 0.41 e Å−3
S = 0.83Δρmin = −1.01 e Å−3
940 reflectionsExtinction correction: SHELXL2014 (Sheldrick, 2015), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
75 parametersExtinction coefficient: 0.046 (3)
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 2-component twin
xyzUiso*/UeqOcc. (<1)
Be10.33330.66670.10240 (12)0.0054 (3)
Al10.50000.00000.00000.00335 (9)
Al20.66670.33330.15613 (3)0.00344 (9)
Al3A−0.33348 (5)−0.16674 (3)0.24468 (2)0.00340 (11)0.983 (3)
Cr3B−0.33348 (5)−0.16674 (3)0.24468 (2)0.00340 (11)0.017 (3)
Al4A0.50000.00000.50000.00331 (15)0.983 (5)
Cr4B0.50000.00000.50000.00331 (15)0.017 (5)
Al50.33330.66670.37276 (3)0.00293 (9)
Mg1A0.00000.00000.40321 (3)0.0040 (2)0.972 (5)
Cr1B0.00000.00000.40321 (3)0.0040 (2)0.028 (5)
Mg2A0.66670.33330.34070 (3)0.0041 (2)0.952 (5)
Cr2B0.66670.33330.34070 (3)0.0041 (2)0.048 (5)
Mg30.00000.00000.10393 (4)0.00473 (11)
O10.66670.33330.44628 (7)0.00471 (17)
O20.66670.33330.05925 (6)0.00435 (18)
O3−0.81376 (7)−0.18624 (7)0.05785 (4)0.00439 (12)
O4−0.81598 (7)−0.18402 (7)0.43966 (4)0.00449 (12)
O5−0.51854 (7)−0.03709 (14)0.30594 (3)0.00497 (12)
O60.00000.00000.29666 (6)0.00458 (18)
O70.33330.66670.18977 (6)0.00459 (18)
O8−0.16175 (6)−0.83825 (6)0.18822 (4)0.00461 (11)
U11U22U33U12U13U23
Be10.0056 (5)0.0056 (5)0.0050 (7)0.0028 (2)0.0000.000
Al10.00339 (12)0.00316 (15)0.00343 (15)0.00158 (7)0.00049 (6)0.00098 (11)
Al20.00375 (12)0.00375 (12)0.00281 (18)0.00188 (6)0.0000.000
Al3A0.00313 (13)0.00356 (12)0.00337 (14)0.00157 (7)0.00005 (8)0.00003 (4)
Cr3B0.00313 (13)0.00356 (12)0.00337 (14)0.00157 (7)0.00005 (8)0.00003 (4)
Al4A0.00349 (17)0.00302 (19)0.00326 (19)0.00151 (10)0.00000 (5)0.00000 (11)
Cr4B0.00349 (17)0.00302 (19)0.00326 (19)0.00151 (10)0.00000 (5)0.00000 (11)
Al50.00329 (12)0.00329 (12)0.00220 (16)0.00165 (6)0.0000.000
Mg1A0.0041 (2)0.0041 (2)0.0039 (3)0.00204 (12)0.0000.000
Cr1B0.0041 (2)0.0041 (2)0.0039 (3)0.00204 (12)0.0000.000
Mg2A0.0043 (2)0.0043 (2)0.0038 (3)0.00215 (11)0.0000.000
Cr2B0.0043 (2)0.0043 (2)0.0038 (3)0.00215 (11)0.0000.000
Mg30.00494 (15)0.00494 (15)0.0043 (2)0.00247 (8)0.0000.000
O10.0045 (2)0.0045 (2)0.0051 (4)0.00226 (12)0.0000.000
O20.0048 (2)0.0048 (2)0.0034 (4)0.00241 (12)0.0000.000
O30.00421 (19)0.00421 (19)0.0045 (3)0.0019 (2)0.00005 (9)−0.00005 (9)
O40.00431 (19)0.00431 (19)0.0049 (3)0.0022 (2)−0.00011 (9)0.00011 (9)
O50.00519 (19)0.0047 (2)0.0049 (3)0.00234 (12)0.00010 (9)0.00020 (18)
O60.0049 (3)0.0049 (3)0.0039 (4)0.00247 (13)0.0000.000
O70.0053 (3)0.0053 (3)0.0031 (4)0.00267 (13)0.0000.000
O80.00479 (18)0.00479 (18)0.0048 (2)0.0028 (2)−0.00033 (10)0.00033 (10)
Be1—O71.602 (2)Mg1A—Al5xiii3.3259 (2)
Be1—O3i1.6615 (13)Mg1A—Al3Aiv3.3376 (6)
Be1—O3ii1.6615 (13)Mg1A—Cr3Biv3.3376 (6)
Be1—O3iii1.6615 (13)Mg1A—Al3Aiii3.3376 (6)
Be1—Al1iv2.4926 (17)Mg1A—Cr3Biii3.3376 (6)
Be1—Al1v2.4926 (17)Mg2A—O5viii1.9300 (7)
Be1—Al1vi2.4926 (17)Mg2A—O5xxiv1.9300 (7)
Al1—O3vii1.8799 (5)Mg2A—O5iii1.9300 (7)
Al1—O3viii1.8799 (5)Mg2A—O11.9361 (13)
Al1—O3ix1.8799 (5)Mg2A—Al5viii3.3310 (2)
Al1—O3x1.8799 (5)Mg2A—Al5xiii3.3310 (2)
Al1—O21.9666 (6)Mg2A—Al3Aiv3.3410 (3)
Al1—O2xi1.9667 (6)Mg2A—Al3Aviii3.3410 (3)
Al1—Be1xii2.4926 (17)Mg2A—Al3Axvi3.3410 (3)
Al1—Be1xiii2.4926 (17)Mg2A—Al3Axxiv3.3410 (3)
Al1—Al1xiv2.8394 (2)Mg2A—Al3Aiii3.3410 (3)
Al1—Al1xv2.8394 (1)Mg3—O3xvii2.0173 (7)
Al1—Al1vi2.8394 (2)Mg3—O3ii2.0173 (7)
Al1—Al1xvi2.8394 (1)Mg3—O3viii2.0173 (7)
Al2—O21.7765 (12)Mg3—O8xvi2.2181 (8)
Al2—O8i1.7874 (7)Mg3—O8v2.2181 (8)
Al2—O8iv1.7874 (7)Mg3—O8xviii2.2181 (8)
Al2—O8xvi1.7874 (7)Mg3—Al3Aiii3.0580 (7)
Al3A—O61.8969 (6)Mg3—Cr3Biii3.0580 (7)
Al3A—O5xvii1.9189 (5)Mg3—Al3Aiv3.0580 (7)
Al3A—O51.9189 (5)Mg3—Cr3Biv3.0580 (7)
Al3A—O8v1.9193 (5)O1—Cr4Bxv1.9125 (6)
Al3A—O8xviii1.9193 (5)O1—Al4Axv1.9125 (6)
Al3A—O7xix1.9232 (6)O1—Cr4Bvi1.9125 (6)
Al3A—Cr3Bxvii2.8381 (5)O1—Al4Avi1.9125 (6)
Al3A—Al3Axvii2.8381 (5)O2—Al1xv1.9666 (6)
Al3A—Al3Axx2.8381 (5)O2—Al1vi1.9666 (6)
Al3A—Cr3Bxx2.8381 (5)O3—Be1xix1.6616 (13)
Al3A—Cr3Biii2.8407 (5)O3—Al1xviii1.8799 (5)
Al3A—Al3Aiii2.8407 (5)O3—Al1xxv1.8799 (5)
Al4A—O1xxi1.9124 (6)O3—Mg3xxv2.0173 (7)
Al4A—O11.9125 (6)O4—Cr4Bxxv1.9133 (5)
Al4A—O4xxii1.9133 (5)O4—Al4Axxv1.9133 (5)
Al4A—O4x1.9133 (5)O4—Cr4Bxviii1.9133 (5)
Al4A—O4xxiii1.9133 (5)O4—Al4Axviii1.9133 (5)
Al4A—O4viii1.9133 (5)O4—Al5xix1.9136 (8)
Al4A—Al4Axiv2.8394 (1)O4—Cr1Bxxv1.9295 (7)
Al4A—Al4Axv2.8394 (1)O4—Mg1Axxv1.9295 (7)
Al4A—Cr4Bxiv2.8394 (1)O5—Al5xix1.9036 (7)
Al4A—Cr4Bxv2.8394 (1)O5—Cr3Bxx1.9188 (5)
Al4A—Al4Avi2.8394 (1)O5—Al3Axx1.9188 (5)
Al4A—Cr4Bvi2.8394 (1)O5—Cr2Bxxv1.9300 (7)
Al5—O5iii1.9037 (7)O5—Mg2Axxv1.9300 (7)
Al5—O5ii1.9037 (7)O6—Cr3Biii1.8969 (6)
Al5—O5i1.9037 (7)O6—Al3Aiii1.8969 (6)
Al5—O4iii1.9136 (8)O6—Cr3Biv1.8969 (6)
Al5—O4ii1.9136 (8)O6—Al3Aiv1.8969 (6)
Al5—O4i1.9136 (8)O7—Cr3Bii1.9232 (6)
Al5—Cr4Bv2.8515 (4)O7—Al3Aii1.9232 (6)
Al5—Al4Av2.8515 (4)O7—Al3Ai1.9232 (6)
Al5—Cr4Biv2.8515 (4)O7—Cr3Bi1.9232 (6)
Al5—Al4Aiv2.8515 (4)O7—Cr3Biii1.9232 (6)
Al5—Cr4Bvi2.8515 (4)O7—Al3Aiii1.9232 (6)
Al5—Al4Avi2.8515 (4)O8—Al2xix1.7874 (7)
Mg1A—O4viii1.9295 (7)O8—Cr3Bx1.9193 (5)
Mg1A—O4ii1.9296 (7)O8—Al3Ax1.9193 (5)
Mg1A—O4xvii1.9296 (7)O8—Al3Axiii1.9193 (5)
Mg1A—O61.9537 (12)O8—Cr3Bxiii1.9193 (5)
Mg1A—Al5xix3.3259 (2)O8—Mg3xiii2.2181 (8)
O7—Be1—O3i119.45 (7)O4viii—Mg1A—O4ii108.66 (2)
O7—Be1—O3ii119.45 (7)O4viii—Mg1A—O4xvii108.66 (2)
O3i—Be1—O3ii97.89 (9)O4ii—Mg1A—O4xvii108.66 (2)
O7—Be1—O3iii119.45 (7)O4viii—Mg1A—O6110.27 (2)
O3i—Be1—O3iii97.89 (9)O4ii—Mg1A—O6110.27 (2)
O3ii—Be1—O3iii97.89 (9)O4xvii—Mg1A—O6110.27 (2)
O7—Be1—Al1iv138.88 (3)O4viii—Mg1A—Al5xix121.368 (4)
O3i—Be1—Al1iv48.95 (5)O4ii—Mg1A—Al5xix121.369 (4)
O3ii—Be1—Al1iv48.95 (5)O4xvii—Mg1A—Al5xix29.94 (2)
O3iii—Be1—Al1iv101.67 (10)O6—Mg1A—Al5xix80.334 (11)
O7—Be1—Al1v138.88 (3)O4viii—Mg1A—Al5121.368 (4)
O3i—Be1—Al1v48.95 (5)O4ii—Mg1A—Al529.94 (2)
O3ii—Be1—Al1v101.67 (10)O4xvii—Mg1A—Al5121.368 (4)
O3iii—Be1—Al1v48.95 (5)O6—Mg1A—Al580.336 (11)
Al1iv—Be1—Al1v69.44 (5)Al5xix—Mg1A—Al5117.240 (6)
O7—Be1—Al1vi138.88 (3)O4viii—Mg1A—Al5xiii29.94 (2)
O3i—Be1—Al1vi101.67 (10)O4ii—Mg1A—Al5xiii121.369 (4)
O3ii—Be1—Al1vi48.95 (5)O4xvii—Mg1A—Al5xiii121.369 (4)
O3iii—Be1—Al1vi48.95 (5)O6—Mg1A—Al5xiii80.334 (11)
Al1iv—Be1—Al1vi69.44 (5)Al5xix—Mg1A—Al5xiii117.239 (6)
Al1v—Be1—Al1vi69.44 (5)Al5—Mg1A—Al5xiii117.240 (6)
O3vii—Al1—O3viii180.00 (4)O4viii—Mg1A—Al3Aiv80.84 (2)
O3vii—Al1—O3ix83.60 (4)O4ii—Mg1A—Al3Aiv122.16 (2)
O3viii—Al1—O3ix96.40 (4)O4xvii—Mg1A—Al3Aiv122.16 (2)
O3vii—Al1—O3x96.40 (4)O6—Mg1A—Al3Aiv29.432 (6)
O3viii—Al1—O3x83.60 (4)Al5xix—Mg1A—Al3Aiv95.507 (12)
O3ix—Al1—O3x180.00 (4)Al5—Mg1A—Al3Aiv95.508 (12)
O3vii—Al1—O284.58 (3)Al5xiii—Mg1A—Al3Aiv50.903 (10)
O3viii—Al1—O295.42 (3)O4viii—Mg1A—Cr3Biv80.84 (2)
O3ix—Al1—O284.58 (3)O4ii—Mg1A—Cr3Biv122.16 (2)
O3x—Al1—O295.42 (3)O4xvii—Mg1A—Cr3Biv122.16 (2)
O3vii—Al1—O2xi95.42 (3)O6—Mg1A—Cr3Biv29.432 (6)
O3viii—Al1—O2xi84.58 (3)Al5xix—Mg1A—Cr3Biv95.507 (12)
O3ix—Al1—O2xi95.42 (3)Al5—Mg1A—Cr3Biv95.508 (12)
O3x—Al1—O2xi84.58 (3)Al5xiii—Mg1A—Cr3Biv50.903 (10)
O2—Al1—O2xi180.0Al3Aiv—Mg1A—Cr3Biv0.000 (5)
O3vii—Al1—Be1xii41.80 (2)O4viii—Mg1A—Al3Aiii122.16 (2)
O3viii—Al1—Be1xii138.20 (2)O4ii—Mg1A—Al3Aiii80.84 (2)
O3ix—Al1—Be1xii41.80 (2)O4xvii—Mg1A—Al3Aiii122.16 (2)
O3x—Al1—Be1xii138.20 (2)O6—Mg1A—Al3Aiii29.432 (6)
O2—Al1—Be1xii82.41 (4)Al5xix—Mg1A—Al3Aiii95.508 (12)
O2xi—Al1—Be1xii97.59 (4)Al5—Mg1A—Al3Aiii50.904 (10)
O3vii—Al1—Be1xiii138.20 (2)Al5xiii—Mg1A—Al3Aiii95.508 (12)
O3viii—Al1—Be1xiii41.80 (2)Al3Aiv—Mg1A—Al3Aiii50.371 (11)
O3ix—Al1—Be1xiii138.20 (2)Cr3Biv—Mg1A—Al3Aiii50.4
O3x—Al1—Be1xiii41.80 (2)O4viii—Mg1A—Cr3Biii122.16 (2)
O2—Al1—Be1xiii97.59 (4)O4ii—Mg1A—Cr3Biii80.84 (2)
O2xi—Al1—Be1xiii82.41 (4)O4xvii—Mg1A—Cr3Biii122.16 (2)
Be1xii—Al1—Be1xiii180.00 (7)O6—Mg1A—Cr3Biii29.432 (6)
O3vii—Al1—Al1xiv139.043 (16)Al5xix—Mg1A—Cr3Biii95.508 (12)
O3viii—Al1—Al1xiv40.957 (16)Al5—Mg1A—Cr3Biii50.904 (10)
O3ix—Al1—Al1xiv95.088 (18)Al5xiii—Mg1A—Cr3Biii95.508 (12)
O3x—Al1—Al1xiv84.912 (18)Al3Aiv—Mg1A—Cr3Biii50.371 (11)
O2—Al1—Al1xiv136.211 (19)Cr3Biv—Mg1A—Cr3Biii50.371 (11)
O2xi—Al1—Al1xiv43.790 (19)Al3Aiii—Mg1A—Cr3Biii0.000 (15)
Be1xii—Al1—Al1xiv124.72 (3)O5viii—Mg2A—O5xxiv109.66 (2)
Be1xiii—Al1—Al1xiv55.28 (3)O5viii—Mg2A—O5iii109.66 (2)
O3vii—Al1—Al1xv40.957 (16)O5xxiv—Mg2A—O5iii109.66 (2)
O3viii—Al1—Al1xv139.043 (16)O5viii—Mg2A—O1109.28 (2)
O3ix—Al1—Al1xv84.912 (18)O5xxiv—Mg2A—O1109.28 (2)
O3x—Al1—Al1xv95.088 (18)O5iii—Mg2A—O1109.28 (2)
O2—Al1—Al1xv43.789 (19)O5viii—Mg2A—Al5viii121.522 (3)
O2xi—Al1—Al1xv136.210 (19)O5xxiv—Mg2A—Al5viii29.45 (2)
Be1xii—Al1—Al1xv55.28 (3)O5iii—Mg2A—Al5viii121.522 (3)
Be1xiii—Al1—Al1xv124.72 (3)O1—Mg2A—Al5viii79.835 (12)
Al1xiv—Al1—Al1xv180.0O5viii—Mg2A—Al5xiii29.45 (2)
O3vii—Al1—Al1vi84.912 (18)O5xxiv—Mg2A—Al5xiii121.522 (3)
O3viii—Al1—Al1vi95.088 (18)O5iii—Mg2A—Al5xiii121.522 (3)
O3ix—Al1—Al1vi40.957 (16)O1—Mg2A—Al5xiii79.835 (12)
O3x—Al1—Al1vi139.043 (16)Al5viii—Mg2A—Al5xiii116.954 (7)
O2—Al1—Al1vi43.789 (19)O5viii—Mg2A—Al5121.521 (4)
O2xi—Al1—Al1vi136.211 (19)O5xxiv—Mg2A—Al5121.521 (3)
Be1xii—Al1—Al1vi55.28 (3)O5iii—Mg2A—Al529.45 (2)
Be1xiii—Al1—Al1vi124.72 (3)O1—Mg2A—Al579.834 (12)
Al1xiv—Al1—Al1vi120.0Al5viii—Mg2A—Al5116.954 (7)
Al1xv—Al1—Al1vi60.0Al5xiii—Mg2A—Al5116.954 (7)
O3vii—Al1—Al1xvi95.088 (18)O5viii—Mg2A—Al3Aiv29.673 (12)
O3viii—Al1—Al1xvi84.912 (18)O5xxiv—Mg2A—Al3Aiv121.37 (3)
O3ix—Al1—Al1xvi139.043 (16)O5iii—Mg2A—Al3Aiv79.990 (15)
O3x—Al1—Al1xvi40.957 (16)O1—Mg2A—Al3Aiv121.802 (9)
O2—Al1—Al1xvi136.211 (19)Al5viii—Mg2A—Al3Aiv144.821 (12)
O2xi—Al1—Al1xvi43.789 (19)Al5xiii—Mg2A—Al3Aiv50.834 (9)
Be1xii—Al1—Al1xvi124.72 (3)Al5—Mg2A—Al3Aiv95.349 (7)
Be1xiii—Al1—Al1xvi55.28 (3)O5viii—Mg2A—Al3Aviii29.674 (12)
Al1xiv—Al1—Al1xvi60.0O5xxiv—Mg2A—Al3Aviii79.990 (15)
Al1xv—Al1—Al1xvi120.0O5iii—Mg2A—Al3Aviii121.37 (3)
Al1vi—Al1—Al1xvi180.0O1—Mg2A—Al3Aviii121.802 (9)
O2—Al2—O8i109.22 (3)Al5viii—Mg2A—Al3Aviii95.348 (7)
O2—Al2—O8iv109.22 (3)Al5xiii—Mg2A—Al3Aviii50.834 (8)
O8i—Al2—O8iv109.72 (3)Al5—Mg2A—Al3Aviii144.822 (12)
O2—Al2—O8xvi109.22 (3)Al3Aiv—Mg2A—Al3Aviii50.270 (9)
O8i—Al2—O8xvi109.72 (3)O5viii—Mg2A—Al3Axvi79.990 (15)
O8iv—Al2—O8xvi109.72 (3)O5xxiv—Mg2A—Al3Axvi29.674 (12)
O6—Al3A—O5xvii96.66 (3)O5iii—Mg2A—Al3Axvi121.37 (3)
O6—Al3A—O596.66 (3)O1—Mg2A—Al3Axvi121.802 (9)
O5xvii—Al3A—O582.22 (4)Al5viii—Mg2A—Al3Axvi50.834 (9)
O6—Al3A—O8v83.72 (3)Al5xiii—Mg2A—Al3Axvi95.348 (7)
O5xvii—Al3A—O8v175.23 (3)Al5—Mg2A—Al3Axvi144.822 (12)
O5—Al3A—O8v93.01 (3)Al3Aiv—Mg2A—Al3Axvi94.786 (12)
O6—Al3A—O8xviii83.72 (3)Al3Aviii—Mg2A—Al3Axvi50.318 (10)
O5xvii—Al3A—O8xviii93.01 (3)O5viii—Mg2A—Al3Axxiv121.37 (3)
O5—Al3A—O8xviii175.23 (3)O5xxiv—Mg2A—Al3Axxiv29.673 (12)
O8v—Al3A—O8xviii91.76 (4)O5iii—Mg2A—Al3Axxiv79.990 (15)
O6—Al3A—O7xix178.60 (4)O1—Mg2A—Al3Axxiv121.802 (9)
O5xvii—Al3A—O7xix84.39 (3)Al5viii—Mg2A—Al3Axxiv50.834 (8)
O5—Al3A—O7xix84.40 (3)Al5xiii—Mg2A—Al3Axxiv144.821 (12)
O8v—Al3A—O7xix95.31 (3)Al5—Mg2A—Al3Axxiv95.349 (7)
O8xviii—Al3A—O7xix95.31 (3)Al3Aiv—Mg2A—Al3Axxiv116.397 (17)
O6—Al3A—Cr3Bxvii138.48 (2)Al3Aviii—Mg2A—Al3Axxiv94.786 (12)
O5xvii—Al3A—Cr3Bxvii42.307 (16)Al3Axvi—Mg2A—Al3Axxiv50.270 (9)
O5—Al3A—Cr3Bxvii85.296 (19)O5viii—Mg2A—Al3Aiii79.989 (15)
O8v—Al3A—Cr3Bxvii137.735 (18)O5xxiv—Mg2A—Al3Aiii121.37 (3)
O8xviii—Al3A—Cr3Bxvii91.271 (18)O5iii—Mg2A—Al3Aiii29.674 (12)
O7xix—Al3A—Cr3Bxvii42.450 (19)O1—Mg2A—Al3Aiii121.802 (9)
O6—Al3A—Al3Axvii138.48 (2)Al5viii—Mg2A—Al3Aiii144.822 (12)
O5xvii—Al3A—Al3Axvii42.307 (16)Al5xiii—Mg2A—Al3Aiii95.349 (7)
O5—Al3A—Al3Axvii85.296 (19)Al5—Mg2A—Al3Aiii50.835 (9)
O8v—Al3A—Al3Axvii137.735 (18)Al3Aiv—Mg2A—Al3Aiii50.317 (10)
O8xviii—Al3A—Al3Axvii91.271 (18)Al3Aviii—Mg2A—Al3Aiii94.786 (12)
O7xix—Al3A—Al3Axvii42.450 (19)Al3Axvi—Mg2A—Al3Aiii116.397 (17)
Cr3Bxvii—Al3A—Al3Axvii0.0Al3Axxiv—Mg2A—Al3Aiii94.786 (12)
O6—Al3A—Al3Axx138.48 (2)O3xvii—Mg3—O3ii103.70 (3)
O5xvii—Al3A—Al3Axx85.296 (19)O3xvii—Mg3—O3viii103.70 (3)
O5—Al3A—Al3Axx42.308 (16)O3ii—Mg3—O3viii103.70 (3)
O8v—Al3A—Al3Axx91.271 (18)O3xvii—Mg3—O8xvi160.59 (4)
O8xviii—Al3A—Al3Axx137.735 (18)O3ii—Mg3—O8xvi88.06 (2)
O7xix—Al3A—Al3Axx42.451 (19)O3viii—Mg3—O8xvi88.06 (2)
Cr3Bxvii—Al3A—Al3Axx60.0O3xvii—Mg3—O8v88.06 (2)
Al3Axvii—Al3A—Al3Axx60.0O3ii—Mg3—O8v88.06 (2)
O6—Al3A—Cr3Bxx138.48 (2)O3viii—Mg3—O8v160.59 (4)
O5xvii—Al3A—Cr3Bxx85.296 (19)O8xvi—Mg3—O8v76.80 (3)
O5—Al3A—Cr3Bxx42.308 (16)O3xvii—Mg3—O8xviii88.064 (19)
O8v—Al3A—Cr3Bxx91.271 (18)O3ii—Mg3—O8xviii160.59 (4)
O8xviii—Al3A—Cr3Bxx137.735 (18)O3viii—Mg3—O8xviii88.06 (2)
O7xix—Al3A—Cr3Bxx42.451 (19)O8xvi—Mg3—O8xviii76.80 (3)
Cr3Bxvii—Al3A—Cr3Bxx60.0O8v—Mg3—O8xviii76.80 (3)
Al3Axvii—Al3A—Cr3Bxx60.0O3xvii—Mg3—Al3A82.33 (2)
Al3Axx—Al3A—Cr3Bxx0.000 (14)O3ii—Mg3—Al3A126.66 (2)
O6—Al3A—Cr3Biii41.52 (2)O3viii—Mg3—Al3A126.66 (2)
O5xvii—Al3A—Cr3Biii137.691 (16)O8xvi—Mg3—Al3A78.26 (3)
O5—Al3A—Cr3Biii94.703 (19)O8v—Mg3—Al3A38.697 (14)
O8v—Al3A—Cr3Biii42.266 (18)O8xviii—Mg3—Al3A38.697 (14)
O8xviii—Al3A—Cr3Biii88.730 (18)O3xvii—Mg3—Al3Aiii126.66 (2)
O7xix—Al3A—Cr3Biii137.552 (19)O3ii—Mg3—Al3Aiii82.33 (2)
Cr3Bxvii—Al3A—Cr3Biii180.0O3viii—Mg3—Al3Aiii126.66 (2)
Al3Axvii—Al3A—Cr3Biii180.0O8xvi—Mg3—Al3Aiii38.697 (14)
Al3Axx—Al3A—Cr3Biii120.0O8v—Mg3—Al3Aiii38.697 (14)
Cr3Bxx—Al3A—Cr3Biii120.0O8xviii—Mg3—Al3Aiii78.26 (3)
O6—Al3A—Al3Aiii41.52 (2)Al3A—Mg3—Al3Aiii55.352 (15)
O5xvii—Al3A—Al3Aiii137.691 (16)O3xvii—Mg3—Cr3Biii126.66 (2)
O5—Al3A—Al3Aiii94.703 (19)O3ii—Mg3—Cr3Biii82.33 (2)
O8v—Al3A—Al3Aiii42.266 (18)O3viii—Mg3—Cr3Biii126.66 (2)
O8xviii—Al3A—Al3Aiii88.730 (18)O8xvi—Mg3—Cr3Biii38.697 (14)
O7xix—Al3A—Al3Aiii137.552 (19)O8v—Mg3—Cr3Biii38.697 (14)
Cr3Bxvii—Al3A—Al3Aiii180.0O8xviii—Mg3—Cr3Biii78.26 (3)
Al3Axvii—Al3A—Al3Aiii180.0Al3A—Mg3—Cr3Biii55.4
Al3Axx—Al3A—Al3Aiii120.0Al3Aiii—Mg3—Cr3Biii0.000 (16)
Cr3Bxx—Al3A—Al3Aiii120.0O3xvii—Mg3—Al3Aiv126.66 (2)
Cr3Biii—Al3A—Al3Aiii0.0O3ii—Mg3—Al3Aiv126.66 (2)
O1xxi—Al4A—O1180.0O3viii—Mg3—Al3Aiv82.33 (2)
O1xxi—Al4A—O4xxii96.18 (3)O8xvi—Mg3—Al3Aiv38.697 (14)
O1—Al4A—O4xxii83.82 (3)O8v—Mg3—Al3Aiv78.26 (3)
O1xxi—Al4A—O4x83.82 (3)O8xviii—Mg3—Al3Aiv38.697 (14)
O1—Al4A—O4x96.18 (3)Al3A—Mg3—Al3Aiv55.352 (15)
O4xxii—Al4A—O4x180.00 (3)Al3Aiii—Mg3—Al3Aiv55.351 (15)
O1xxi—Al4A—O4xxiii96.18 (3)Cr3Biii—Mg3—Al3Aiv55.4
O1—Al4A—O4xxiii83.82 (3)O3xvii—Mg3—Cr3Biv126.66 (2)
O4xxii—Al4A—O4xxiii83.33 (4)O3ii—Mg3—Cr3Biv126.66 (2)
O4x—Al4A—O4xxiii96.67 (4)O3viii—Mg3—Cr3Biv82.33 (2)
O1xxi—Al4A—O4viii83.82 (3)O8xvi—Mg3—Cr3Biv38.697 (14)
O1—Al4A—O4viii96.18 (3)O8v—Mg3—Cr3Biv78.26 (3)
O4xxii—Al4A—O4viii96.67 (4)O8xviii—Mg3—Cr3Biv38.697 (14)
O4x—Al4A—O4viii83.33 (4)Al3A—Mg3—Cr3Biv55.4
O4xxiii—Al4A—O4viii180.0Al3Aiii—Mg3—Cr3Biv55.351 (15)
O1xxi—Al4A—Al4Axiv42.07 (2)Cr3Biii—Mg3—Cr3Biv55.351 (15)
O1—Al4A—Al4Axiv137.93 (2)Al3Aiv—Mg3—Cr3Biv0.000 (6)
O4xxii—Al4A—Al4Axiv94.432 (19)Cr4Bxv—O1—Al4Axv0.0
O4x—Al4A—Al4Axiv85.568 (19)Cr4Bxv—O1—Al4A95.9
O4xxiii—Al4A—Al4Axiv137.904 (15)Al4Axv—O1—Al4A95.86 (4)
O4viii—Al4A—Al4Axiv42.096 (15)Cr4Bxv—O1—Cr4Bvi95.86 (4)
O1xxi—Al4A—Al4Axv137.93 (2)Al4Axv—O1—Cr4Bvi95.86 (4)
O1—Al4A—Al4Axv42.07 (2)Al4A—O1—Cr4Bvi95.9
O4xxii—Al4A—Al4Axv85.568 (19)Cr4Bxv—O1—Al4Avi95.9
O4x—Al4A—Al4Axv94.432 (19)Al4Axv—O1—Al4Avi95.86 (4)
O4xxiii—Al4A—Al4Axv42.096 (15)Al4A—O1—Al4Avi95.86 (4)
O4viii—Al4A—Al4Axv137.904 (15)Cr4Bvi—O1—Al4Avi0.0
Al4Axiv—Al4A—Al4Axv180.0Cr4Bxv—O1—Mg2A121.00 (3)
O1xxi—Al4A—Cr4Bxiv42.07 (2)Al4Axv—O1—Mg2A121.00 (3)
O1—Al4A—Cr4Bxiv137.93 (2)Al4A—O1—Mg2A121.00 (3)
O4xxii—Al4A—Cr4Bxiv94.432 (19)Cr4Bvi—O1—Mg2A121.00 (3)
O4x—Al4A—Cr4Bxiv85.568 (19)Al4Avi—O1—Mg2A121.00 (3)
O4xxiii—Al4A—Cr4Bxiv137.904 (15)Al2—O2—Al1123.53 (3)
O4viii—Al4A—Cr4Bxiv42.096 (15)Al2—O2—Al1xv123.53 (3)
Al4Axiv—Al4A—Cr4Bxiv0.0Al1—O2—Al1xv92.42 (4)
Al4Axv—Al4A—Cr4Bxiv180.0Al2—O2—Al1vi123.53 (3)
O1xxi—Al4A—Cr4Bxv137.93 (2)Al1—O2—Al1vi92.42 (4)
O1—Al4A—Cr4Bxv42.07 (2)Al1xv—O2—Al1vi92.42 (4)
O4xxii—Al4A—Cr4Bxv85.568 (19)Be1xix—O3—Al1xviii89.25 (5)
O4x—Al4A—Cr4Bxv94.432 (19)Be1xix—O3—Al1xxv89.25 (5)
O4xxiii—Al4A—Cr4Bxv42.096 (15)Al1xviii—O3—Al1xxv98.09 (3)
O4viii—Al4A—Cr4Bxv137.904 (15)Be1xix—O3—Mg3xxv125.79 (8)
Al4Axiv—Al4A—Cr4Bxv180.0Al1xviii—O3—Mg3xxv122.63 (2)
Al4Axv—Al4A—Cr4Bxv0.0Al1xxv—O3—Mg3xxv122.63 (2)
Cr4Bxiv—Al4A—Cr4Bxv180.0Cr4Bxxv—O4—Al4Axxv0.0
O1xxi—Al4A—Al4Avi137.93 (2)Cr4Bxxv—O4—Cr4Bxviii95.81 (3)
O1—Al4A—Al4Avi42.07 (2)Al4Axxv—O4—Cr4Bxviii95.81 (3)
O4xxii—Al4A—Al4Avi42.096 (15)Cr4Bxxv—O4—Al4Axviii95.8
O4x—Al4A—Al4Avi137.904 (15)Al4Axxv—O4—Al4Axviii95.81 (3)
O4xxiii—Al4A—Al4Avi85.569 (18)Cr4Bxviii—O4—Al4Axviii0.0
O4viii—Al4A—Al4Avi94.431 (18)Cr4Bxxv—O4—Al5xix96.34 (3)
Al4Axiv—Al4A—Al4Avi120.0Al4Axxv—O4—Al5xix96.34 (3)
Al4Axv—Al4A—Al4Avi60.0Cr4Bxviii—O4—Al5xix96.34 (3)
Cr4Bxiv—Al4A—Al4Avi120.0Al4Axviii—O4—Al5xix96.34 (3)
Cr4Bxv—Al4A—Al4Avi60.0Cr4Bxxv—O4—Cr1Bxxv121.23 (2)
O1xxi—Al4A—Cr4Bvi137.93 (2)Al4Axxv—O4—Cr1Bxxv121.23 (2)
O1—Al4A—Cr4Bvi42.07 (2)Cr4Bxviii—O4—Cr1Bxxv121.23 (2)
O4xxii—Al4A—Cr4Bvi42.096 (15)Al4Axviii—O4—Cr1Bxxv121.23 (2)
O4x—Al4A—Cr4Bvi137.904 (15)Al5xix—O4—Cr1Bxxv119.86 (4)
O4xxiii—Al4A—Cr4Bvi85.569 (18)Cr4Bxxv—O4—Mg1Axxv121.23 (2)
O4viii—Al4A—Cr4Bvi94.431 (18)Al4Axxv—O4—Mg1Axxv121.23 (2)
Al4Axiv—Al4A—Cr4Bvi120.0Cr4Bxviii—O4—Mg1Axxv121.23 (2)
Al4Axv—Al4A—Cr4Bvi60.0Al4Axviii—O4—Mg1Axxv121.23 (2)
Cr4Bxiv—Al4A—Cr4Bvi120.0Al5xix—O4—Mg1Axxv119.86 (4)
Cr4Bxv—Al4A—Cr4Bvi60.0Cr1Bxxv—O4—Mg1Axxv0.0
Al4Avi—Al4A—Cr4Bvi0.0Al5xix—O5—Cr3Bxx97.03 (3)
O5iii—Al5—O5ii83.03 (3)Al5xix—O5—Al3Axx97.03 (3)
O5iii—Al5—O5i83.03 (3)Cr3Bxx—O5—Al3Axx0.0
O5ii—Al5—O5i83.02 (3)Al5xix—O5—Al3A97.03 (3)
O5iii—Al5—O4iii96.83 (2)Cr3Bxx—O5—Al3A95.4
O5ii—Al5—O4iii179.81 (3)Al3Axx—O5—Al3A95.38 (3)
O5i—Al5—O4iii96.83 (2)Al5xix—O5—Cr2Bxxv120.65 (4)
O5iii—Al5—O4ii96.83 (2)Cr3Bxx—O5—Cr2Bxxv120.46 (2)
O5ii—Al5—O4ii96.83 (2)Al3Axx—O5—Cr2Bxxv120.46 (2)
O5i—Al5—O4ii179.81 (3)Al3A—O5—Cr2Bxxv120.46 (2)
O4iii—Al5—O4ii83.31 (3)Al5xix—O5—Mg2Axxv120.65 (4)
O5iii—Al5—O4i179.81 (3)Cr3Bxx—O5—Mg2Axxv120.46 (2)
O5ii—Al5—O4i96.83 (2)Al3Axx—O5—Mg2Axxv120.46 (2)
O5i—Al5—O4i96.83 (2)Al3A—O5—Mg2Axxv120.46 (2)
O4iii—Al5—O4i83.31 (3)Cr2Bxxv—O5—Mg2Axxv0.0
O4ii—Al5—O4i83.31 (3)Cr3Biii—O6—Al3Aiii0.0
O5iii—Al5—Cr4Bv138.301 (15)Cr3Biii—O6—Cr3Biv96.97 (4)
O5ii—Al5—Cr4Bv138.300 (15)Al3Aiii—O6—Cr3Biv96.97 (4)
O5i—Al5—Cr4Bv94.97 (2)Cr3Biii—O6—Al3Aiv97.0
O4iii—Al5—Cr4Bv41.825 (15)Al3Aiii—O6—Al3Aiv96.97 (4)
O4ii—Al5—Cr4Bv85.22 (2)Cr3Biv—O6—Al3Aiv0.0
O4i—Al5—Cr4Bv41.826 (15)Cr3Biii—O6—Al3A97.0
O5iii—Al5—Al4Av138.301 (15)Al3Aiii—O6—Al3A96.97 (4)
O5ii—Al5—Al4Av138.300 (15)Cr3Biv—O6—Al3A97.0
O5i—Al5—Al4Av94.97 (2)Al3Aiv—O6—Al3A96.97 (4)
O4iii—Al5—Al4Av41.825 (15)Cr3Biii—O6—Mg1A120.16 (3)
O4ii—Al5—Al4Av85.22 (2)Al3Aiii—O6—Mg1A120.16 (3)
O4i—Al5—Al4Av41.826 (15)Cr3Biv—O6—Mg1A120.16 (3)
Cr4Bv—Al5—Al4Av0.0Al3Aiv—O6—Mg1A120.16 (3)
O5iii—Al5—Cr4Biv138.301 (15)Al3A—O6—Mg1A120.16 (3)
O5ii—Al5—Cr4Biv94.97 (2)Be1—O7—Cr3Bii121.57 (3)
O5i—Al5—Cr4Biv138.300 (15)Be1—O7—Al3Aii121.57 (3)
O4iii—Al5—Cr4Biv85.22 (2)Cr3Bii—O7—Al3Aii0.0
O4ii—Al5—Cr4Biv41.825 (15)Be1—O7—Al3Ai121.57 (3)
O4i—Al5—Cr4Biv41.826 (15)Cr3Bii—O7—Al3Ai95.1
Cr4Bv—Al5—Cr4Biv59.719 (10)Al3Aii—O7—Al3Ai95.10 (4)
Al4Av—Al5—Cr4Biv59.719 (10)Be1—O7—Cr3Bi121.57 (3)
O5iii—Al5—Al4Aiv138.301 (15)Cr3Bii—O7—Cr3Bi95.10 (4)
O5ii—Al5—Al4Aiv94.97 (2)Al3Aii—O7—Cr3Bi95.10 (4)
O5i—Al5—Al4Aiv138.300 (15)Al3Ai—O7—Cr3Bi0.000 (18)
O4iii—Al5—Al4Aiv85.22 (2)Be1—O7—Cr3Biii121.57 (3)
O4ii—Al5—Al4Aiv41.825 (15)Cr3Bii—O7—Cr3Biii95.10 (4)
O4i—Al5—Al4Aiv41.826 (15)Al3Aii—O7—Cr3Biii95.10 (4)
Cr4Bv—Al5—Al4Aiv59.7Al3Ai—O7—Cr3Biii95.10 (4)
Al4Av—Al5—Al4Aiv59.719 (10)Cr3Bi—O7—Cr3Biii95.10 (4)
Cr4Biv—Al5—Al4Aiv0.0Be1—O7—Al3Aiii121.57 (3)
O5iii—Al5—Cr4Bvi94.97 (2)Cr3Bii—O7—Al3Aiii95.1
O5ii—Al5—Cr4Bvi138.301 (15)Al3Aii—O7—Al3Aiii95.10 (4)
O5i—Al5—Cr4Bvi138.301 (15)Al3Ai—O7—Al3Aiii95.10 (4)
O4iii—Al5—Cr4Bvi41.826 (15)Cr3Bi—O7—Al3Aiii95.1
O4ii—Al5—Cr4Bvi41.826 (15)Cr3Biii—O7—Al3Aiii0.0
O4i—Al5—Cr4Bvi85.22 (2)Al2xix—O8—Cr3Bx123.84 (2)
Cr4Bv—Al5—Cr4Bvi59.719 (10)Al2xix—O8—Al3Ax123.84 (2)
Al4Av—Al5—Cr4Bvi59.719 (10)Cr3Bx—O8—Al3Ax0.0
Cr4Biv—Al5—Cr4Bvi59.719 (10)Al2xix—O8—Al3Axiii123.84 (2)
Al4Aiv—Al5—Cr4Bvi59.719 (10)Cr3Bx—O8—Al3Axiii95.5
O5iii—Al5—Al4Avi94.97 (2)Al3Ax—O8—Al3Axiii95.47 (4)
O5ii—Al5—Al4Avi138.301 (15)Al2xix—O8—Cr3Bxiii123.84 (2)
O5i—Al5—Al4Avi138.301 (15)Cr3Bx—O8—Cr3Bxiii95.47 (4)
O4iii—Al5—Al4Avi41.826 (15)Al3Ax—O8—Cr3Bxiii95.47 (4)
O4ii—Al5—Al4Avi41.826 (15)Al3Axiii—O8—Cr3Bxiii0.000 (17)
O4i—Al5—Al4Avi85.22 (2)Al2xix—O8—Mg3xiii116.60 (4)
Cr4Bv—Al5—Al4Avi59.7Cr3Bx—O8—Mg3xiii95.04 (3)
Al4Av—Al5—Al4Avi59.719 (10)Al3Ax—O8—Mg3xiii95.04 (3)
Cr4Biv—Al5—Al4Avi59.7Al3Axiii—O8—Mg3xiii95.04 (3)
Al4Aiv—Al5—Al4Avi59.719 (10)Cr3Bxiii—O8—Mg3xiii95.04 (3)
Cr4Bvi—Al5—Al4Avi0.0
  3 in total

1.  Crystal and magnetic structures of the brownmillerite Ca2Cr2O5.

Authors:  Angel M Arevalo-Lopez; J Paul Attfield
Journal:  Dalton Trans       Date:  2015-01-27       Impact factor: 4.390

2.  Chromium Environment within Cr-Doped BaAl2O4: Correlation of X-ray Diffraction and X-ray Absorption Spectroscopy Investigations.

Authors:  Martina Vrankić; Biserka Gržeta; Dirk Lützenkirchen-Hecht; Sanja Bosnar; Ankica Šarić
Journal:  Inorg Chem       Date:  2015-11-20       Impact factor: 5.165

3.  Crystal structure refinement with SHELXL.

Authors:  George M Sheldrick
Journal:  Acta Crystallogr C Struct Chem       Date:  2015-01-01       Impact factor: 1.172
  3 in total

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