Crystal structure of the solid solution (Sr_1.65Pb_0.35)Al₆O₁₁

The title compound, di(strontium/lead) hexa­aluminate, is a member of the solid solution series (Sr_2-xPb_x)Al₆O₁₁. It contains two statistically occupied M²⁺ (M = Sr, Pb) sites [both with site symmetries ..m; Sr:Pb occupancy ratios = 0.756 (2):0.244 (2) and 0.8968 (19):0.1032 (19)] that are located in the voids of an aluminate framework. The M²⁺ sites are surrounded by six and seven O atoms, respectively, if a cut-off M—O distance of 3 Å is chosen, resulting in considerably distorted MO_x polyhedra. The aluminate framework consists of three AlO₆ octa­hedra (two with point-group symmetries ..2/m and one with ..2) sharing edges to form partially filled layers extending parallel to (100) and located at x = 0, 0.5. Adjacent AlO₆ layers are linked by a network made up from two crystallographically different AlO₄ tetra­hedra by sharing corners.

1. Related literature

The title compound was obtained during experiments to prepare the strontium analogue of the lead calcium aluminate PbCa₂Al₈O₁₅ (Artner & Weil, 2012). For another member of the isotypic solid solution series (Sr_2-xPb_x)Al₆O₁₁ with a different Sr:Pb ratio, see: Plötz & Müller-Buschbaum (1982).

2. Experimental

2.1. Crystal data

• (Sr_1.65Pb_0.35)Al₆O₁₁

• M_r = 555.27

• Orthorhombic, P n n m

• a = 22.0299 (4) Å

• b = 4.8802 (1) Å

• c = 8.3995 (2) Å

• V = 903.03 (3) ų

• Z = 4

• Mo Kα radiation

• μ = 16.94 mm⁻¹

• T = 296 K

• 0.12 × 0.05 × 0.05 mm

2.2. Data collection

• Bruker SMART CCD diffractometer

• Absorption correction: multi-scan (SADABS; Bruker, 2008) T_min = 0.236, T_max = 0.485

• 10434 measured reflections

• 2509 independent reflections

• 2190 reflections with I > 2σ(I)

• R_int = 0.042

2.3. Refinement

• R[F² > 2σ(F²)] = 0.027

• wR(F²) = 0.061

• S = 1.05

• 2509 reflections

• 101 parameters

• Δρ_max = 1.12 e Å⁻³

• Δρ_min = −1.51 e Å⁻³

Data collection: SMART (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ATOMS for Windows (Dowty, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).

Supporting information

Related literature

The title compound was obtained during experiments to prepare the strontium analogue of the lead calcium aluminate PbCa₂Al₈O₁₅ (Artner & Weil, 2012). For another member of the isotypic solid solution series (Sr_{2 - x}Pb_x)Al₆O₁₁ with a different Sr:Pb ratio, see: Plötz & Müller-Buschbaum (1982).

S1. Experimental

A mixture of 2PbCO₃^.Pb(OH)₂, SrCO₃ and Al(OH)₃ (molar ratio 1:6:24) was heated in a platinum crucible over a period of 24 h to 1233 K, kept at this temperature for 10 h and cooled over a period of 24 h to room temperature. A few colourless platy crystals of the title compound grew on top of a brick-red microcrystalline matrix that was not further analysed.

S2. Refinement

Atom labels and starting parameters for refinement were taken from the isotypic compound (Sr_1.33Pb_0.67)Al₆O₁₁ (Plötz & Müller-Buschbaum, 1982). The two M²⁺ sites are statistically occupied by Pb and Sr. For each site, full occupancy was considered and the occupancy factors refined independently. The highest and lowest remaining electron densities are located 0.64 Å and 0.72 Å, respectively, from the site (Sr1/Pb1).

Computing details

Data collection: SMART (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ATOMS for Windows (Dowty, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures

	Fig. 1. The crystal structure of (Sr1.65Pb0.35)Al6O11 in a projection along [010]. AlO6 octahedra are yellow, AlO4 octahedra are red. Displacement ellipsoids are drawn at the 97% probability level. Bonds to the statistically occupied M^2+ sites (M = Sr, Pb) were omitted for clarity. [Symmetry code: i) x + 1/2, y, z.]
	Fig. 2. The crystal structure of (Sr1.65Pb0.35)Al6O11 in a projection along [100] showing one layer of edge-sharing AlO6 octahedra and the connecting layer of corner-sharing AlO4 tetrahedra as well as one layer of M^2+ sites (M = Sr, Pb). Colour code and displacement ellipsoids are as in Fig. 1.

Di(strontium/lead) hexaaluminate

Crystal data

(Sr1.65Pb0.35)Al6O11	F(000) = 1030
Mr = 555.27	Dx = 4.084 Mg m^−3
Orthorhombic, Pnnm	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2 2n	Cell parameters from 3598 reflections
a = 22.0299 (4) Å	θ = 3.7–32.5°
b = 4.8802 (1) Å	µ = 16.94 mm^−1
c = 8.3995 (2) Å	T = 296 K
V = 903.03 (3) Å^3	Plate, colourless
Z = 4	0.12 × 0.05 × 0.05 mm

Data collection

Bruker SMART CCD diffractometer	2509 independent reflections
Radiation source: fine-focus sealed tube	2190 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.042
ω scans	θmax = 37.5°, θmin = 3.7°
Absorption correction: multi-scan (SADABS; Bruker, 2008)	h = −30→37
Tmin = 0.236, Tmax = 0.485	k = −6→8
10434 measured reflections	l = −14→9

Refinement

Refinement on F^2	Primary atom site location: isomorphous structure methods
Least-squares matrix: full	w = 1/[σ^2(Fo^2) + (0.0244P)^2 + 0.7036P] where P = (Fo^2 + 2Fc^2)/3
R[F^2 > 2σ(F^2)] = 0.027	(Δ/σ)max = 0.001
wR(F^2) = 0.061	Δρmax = 1.12 e Å^−3
S = 1.05	Δρmin = −1.51 e Å^−3
2509 reflections	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
101 parameters	Extinction coefficient: 0.0022 (3)
0 restraints

Special details

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Pb1	0.364795 (11)	0.12254 (4)	0.0000	0.01369 (7)	0.756 (2)
Pb2	0.155369 (11)	0.54620 (5)	0.0000	0.01112 (8)	0.8968 (19)
Sr1	0.364795 (11)	0.12254 (4)	0.0000	0.01369 (7)	0.244 (2)
Sr2	0.155369 (11)	0.54620 (5)	0.0000	0.01112 (8)	0.1032 (19)
Al1	0.0000	0.0000	0.5000	0.00496 (19)
Al2	0.0000	0.5000	0.0000	0.00509 (19)
Al3	0.0000	0.5000	0.66773 (9)	0.00472 (14)
Al4	0.21348 (3)	0.11886 (11)	0.29528 (7)	0.00638 (12)
Al5	0.07460 (3)	0.00878 (11)	0.17903 (6)	0.00472 (11)
O1	0.05605 (9)	0.8271 (4)	0.0000	0.0055 (3)
O2	0.29866 (14)	0.5677 (5)	0.0000	0.0197 (5)
O3	0.45181 (6)	0.3230 (3)	0.84219 (15)	0.0060 (2)
O4	0.34669 (7)	0.4960 (3)	0.31766 (19)	0.0118 (3)
O5	0.45552 (9)	0.8297 (4)	0.0000	0.0055 (3)
O6	0.95192 (6)	0.6515 (3)	0.83661 (15)	0.0062 (2)
O7	0.28328 (7)	0.9728 (3)	0.24121 (19)	0.0117 (3)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Pb1	0.01691 (12)	0.01109 (9)	0.01306 (9)	0.00260 (7)	0.000	0.000
Pb2	0.00748 (12)	0.01603 (12)	0.00985 (10)	0.00238 (8)	0.000	0.000
Sr1	0.01691 (12)	0.01109 (9)	0.01306 (9)	0.00260 (7)	0.000	0.000
Sr2	0.00748 (12)	0.01603 (12)	0.00985 (10)	0.00238 (8)	0.000	0.000
Al1	0.0059 (5)	0.0041 (4)	0.0049 (4)	−0.0004 (4)	0.000	0.000
Al2	0.0039 (5)	0.0070 (4)	0.0044 (4)	0.0012 (4)	0.000	0.000
Al3	0.0043 (3)	0.0048 (3)	0.0050 (3)	0.0001 (2)	0.000	0.000
Al4	0.0049 (3)	0.0067 (2)	0.0075 (2)	−0.00021 (18)	−0.00054 (18)	0.00025 (16)
Al5	0.0035 (2)	0.0052 (2)	0.0054 (2)	−0.00008 (18)	0.00009 (17)	0.00014 (16)
O1	0.0041 (8)	0.0060 (7)	0.0063 (7)	−0.0011 (6)	0.000	0.000
O2	0.0319 (15)	0.0187 (10)	0.0086 (8)	0.0063 (10)	0.000	0.000
O3	0.0058 (6)	0.0064 (5)	0.0058 (5)	0.0007 (4)	−0.0006 (4)	0.0001 (4)
O4	0.0046 (6)	0.0151 (6)	0.0157 (6)	−0.0009 (5)	−0.0023 (5)	0.0065 (5)
O5	0.0065 (8)	0.0045 (7)	0.0055 (6)	−0.0002 (6)	0.000	0.000
O6	0.0058 (6)	0.0063 (5)	0.0065 (5)	0.0013 (4)	−0.0007 (4)	0.0000 (4)
O7	0.0067 (6)	0.0087 (6)	0.0196 (7)	0.0000 (5)	−0.0011 (5)	−0.0016 (5)

Geometric parameters (Å, º)

Pb1—O5^i	2.4569 (19)	Al1—O3^vii	1.9055 (13)
Pb1—O3^ii	2.5275 (13)	Al1—O3^xv	1.9055 (13)
Pb1—O3^iii	2.5275 (13)	Al2—O6^xi	1.8847 (13)
Pb1—O2	2.616 (3)	Al2—O6^xvi	1.8847 (13)
Pb1—O7^iv	2.8042 (16)	Al2—O6^xvii	1.8847 (13)
Pb1—O7^i	2.8042 (16)	Al2—O6^x	1.8847 (13)
Pb1—O2^i	3.075 (3)	Al2—O1	2.0181 (19)
Pb1—O4	3.2558 (17)	Al2—O1^xviii	2.0181 (19)
Pb1—O4^v	3.2558 (17)	Al3—O3^xv	1.9021 (13)
Pb2—O1	2.582 (2)	Al3—O3^xix	1.9021 (13)
Pb2—O7^vi	2.5846 (16)	Al3—O5^xx	1.9067 (14)
Pb2—O7^vii	2.5846 (16)	Al3—O5^vi	1.9067 (14)
Pb2—O4^viii	2.6771 (15)	Al3—O6^xxi	1.9186 (14)
Pb2—O4^ix	2.6771 (15)	Al3—O6^xxii	1.9186 (14)
Pb2—O6^x	2.8983 (14)	Al4—O4^vi	1.7368 (16)
Pb2—O6^xi	2.8983 (14)	Al4—O7^i	1.7548 (17)
Pb2—O4^vii	3.0914 (17)	Al4—O7^vi	1.7556 (16)
Pb2—O4^vi	3.0914 (17)	Al4—O2^vi	1.7581 (8)
Pb2—O2	3.158 (3)	Al5—O4^vi	1.7352 (16)
Al1—O5^xii	1.8841 (18)	Al5—O3^vii	1.7433 (14)
Al1—O5^vi	1.8841 (18)	Al5—O6^xi	1.7627 (14)
Al1—O3^xiii	1.9055 (13)	Al5—O1^i	1.7929 (11)
Al1—O3^xiv	1.9055 (13)
O5^i—Pb1—O3^ii	66.93 (5)	O6^xvii—Al2—O6^x	180.0
O5^i—Pb1—O3^iii	66.93 (5)	O6^xi—Al2—O1	88.08 (5)
O3^ii—Pb1—O3^iii	63.26 (6)	O6^xvi—Al2—O1	91.92 (5)
O5^i—Pb1—O2	159.41 (8)	O6^xvii—Al2—O1	91.92 (5)
O3^ii—Pb1—O2	95.80 (6)	O6^x—Al2—O1	88.08 (5)
O3^iii—Pb1—O2	95.80 (6)	O6^xi—Al2—O1^xviii	91.92 (5)
O5^i—Pb1—O7^iv	111.67 (4)	O6^xvi—Al2—O1^xviii	88.08 (5)
O3^ii—Pb1—O7^iv	164.89 (4)	O6^xvii—Al2—O1^xviii	88.08 (5)
O3^iii—Pb1—O7^iv	101.98 (4)	O6^x—Al2—O1^xviii	91.92 (5)
O2—Pb1—O7^iv	81.94 (5)	O1—Al2—O1^xviii	180.0
O5^i—Pb1—O7^i	111.67 (4)	O3^xv—Al3—O3^xix	174.98 (9)
O3^ii—Pb1—O7^i	101.98 (4)	O3^xv—Al3—O5^xx	92.40 (7)
O3^iii—Pb1—O7^i	164.89 (4)	O3^xix—Al3—O5^xx	83.88 (7)
O2—Pb1—O7^i	81.94 (5)	O3^xv—Al3—O5^vi	83.88 (7)
O7^iv—Pb1—O7^i	92.52 (6)	O3^xix—Al3—O5^vi	92.40 (7)
O5^i—Pb1—O2^i	82.72 (7)	O5^xx—Al3—O5^vi	84.72 (9)
O3^ii—Pb1—O2^i	134.44 (5)	O3^xv—Al3—O6^xxi	91.22 (6)
O3^iii—Pb1—O2^i	134.44 (5)	O3^xix—Al3—O6^xxi	92.49 (6)
O2—Pb1—O2^i	117.87 (11)	O5^xx—Al3—O6^xxi	176.38 (7)
O7^iv—Pb1—O2^i	57.79 (4)	O5^vi—Al3—O6^xxi	95.43 (6)
O7^i—Pb1—O2^i	57.79 (4)	O3^xv—Al3—O6^xxii	92.49 (6)
O5^i—Pb1—O4	115.16 (3)	O3^xix—Al3—O6^xxii	91.22 (6)
O3^ii—Pb1—O4	56.39 (4)	O5^xx—Al3—O6^xxii	95.43 (6)
O3^iii—Pb1—O4	107.82 (4)	O5^vi—Al3—O6^xxii	176.38 (7)
O2—Pb1—O4	57.78 (3)	O6^xxi—Al3—O6^xxii	84.65 (9)
O7^iv—Pb1—O4	131.27 (4)	O4^vi—Al4—O7^i	112.79 (8)
O7^i—Pb1—O4	58.36 (4)	O4^vi—Al4—O7^vi	105.98 (8)
O2^i—Pb1—O4	115.78 (3)	O7^i—Al4—O7^vi	108.60 (6)
O5^i—Pb1—O4^v	115.16 (3)	O4^vi—Al4—O2^vi	111.66 (11)
O3^ii—Pb1—O4^v	107.82 (4)	O7^i—Al4—O2^vi	109.19 (12)
O3^iii—Pb1—O4^v	56.39 (4)	O7^vi—Al4—O2^vi	108.46 (10)
O2—Pb1—O4^v	57.78 (3)	O4^vi—Al5—O3^vii	107.59 (8)
O7^iv—Pb1—O4^v	58.36 (4)	O4^vi—Al5—O6^xi	111.47 (7)
O7^i—Pb1—O4^v	131.27 (4)	O3^vii—Al5—O6^xi	115.93 (7)
O2^i—Pb1—O4^v	115.78 (3)	O4^vi—Al5—O1^i	102.91 (8)
O4—Pb1—O4^v	110.07 (5)	O3^vii—Al5—O1^i	109.03 (7)
O1—Pb2—O7^vi	121.11 (4)	O6^xi—Al5—O1^i	109.09 (7)
O1—Pb2—O7^vii	121.11 (4)	Al5^xxiii—O1—Al5^xxiv	114.01 (10)
O7^vi—Pb2—O7^vii	114.50 (7)	Al5^xxiii—O1—Al2	122.05 (6)
O1—Pb2—O4^viii	63.27 (5)	Al5^xxiv—O1—Al2	122.05 (6)
O7^vi—Pb2—O4^viii	68.99 (5)	Al5^xxiii—O1—Pb2	93.98 (7)
O7^vii—Pb2—O4^viii	127.14 (5)	Al5^xxiv—O1—Pb2	93.98 (7)
O1—Pb2—O4^ix	63.27 (4)	Al2—O1—Pb2	95.65 (7)
O7^vi—Pb2—O4^ix	127.14 (5)	Al4^ix—O2—Al4^viii	155.98 (17)
O7^vii—Pb2—O4^ix	68.99 (5)	Al4^ix—O2—Pb1	101.69 (8)
O4^viii—Pb2—O4^ix	69.79 (7)	Al4^viii—O2—Pb1	101.69 (8)
O1—Pb2—O6^x	59.05 (4)	Al4^ix—O2—Pb1^xxiii	86.97 (9)
O7^vi—Pb2—O6^x	141.12 (4)	Al4^viii—O2—Pb1^xxiii	86.97 (9)
O7^vii—Pb2—O6^x	88.97 (4)	Pb1—O2—Pb1^xxiii	117.87 (11)
O4^viii—Pb2—O6^x	122.01 (4)	Al4^ix—O2—Pb2	81.53 (10)
O4^ix—Pb2—O6^x	89.33 (4)	Al4^viii—O2—Pb2	81.53 (10)
O1—Pb2—O6^xi	59.05 (4)	Pb1—O2—Pb2	121.94 (10)
O7^vi—Pb2—O6^xi	88.97 (4)	Pb1^xxiii—O2—Pb2	120.19 (8)
O7^vii—Pb2—O6^xi	141.12 (4)	Al5^xxv—O3—Al3^xiv	125.65 (8)
O4^viii—Pb2—O6^xi	89.33 (4)	Al5^xxv—O3—Al1^xix	119.80 (7)
O4^ix—Pb2—O6^xi	122.01 (4)	Al3^xiv—O3—Al1^xix	95.46 (6)
O6^x—Pb2—O6^xi	56.52 (5)	Al5^xxv—O3—Pb1^xxvi	111.13 (7)
O1—Pb2—O4^vii	116.66 (5)	Al3^xiv—O3—Pb1^xxvi	97.22 (5)
O7^vi—Pb2—O4^vii	107.69 (4)	Al1^xix—O3—Pb1^xxvi	103.48 (5)
O7^vii—Pb2—O4^vii	58.03 (4)	Al5^xxv—O3—Sr1^xxvi	111.13 (7)
O4^viii—Pb2—O4^vii	174.49 (4)	Al3^xiv—O3—Sr1^xxvi	97.22 (5)
O4^ix—Pb2—O4^vii	115.37 (5)	Al1^xix—O3—Sr1^xxvi	103.48 (5)
O6^x—Pb2—O4^vii	57.61 (4)	Al5^viii—O4—Al4^viii	139.38 (10)
O6^xi—Pb2—O4^vii	86.18 (4)	Al5^viii—O4—Pb2^vi	92.13 (6)
O1—Pb2—O4^vi	116.66 (5)	Al4^viii—O4—Pb2^vi	125.63 (8)
O7^vi—Pb2—O4^vi	58.03 (4)	Al5^viii—O4—Sr2^vi	92.13 (6)
O7^vii—Pb2—O4^vi	107.69 (4)	Al4^viii—O4—Sr2^vi	125.63 (8)
O4^viii—Pb2—O4^vi	115.37 (5)	Al5^viii—O4—Pb2^viii	88.60 (6)
O4^ix—Pb2—O4^vi	174.49 (4)	Al4^viii—O4—Pb2^viii	87.68 (6)
O6^x—Pb2—O4^vi	86.18 (4)	Pb2^vi—O4—Pb2^viii	115.37 (5)
O6^xi—Pb2—O4^vi	57.61 (4)	Sr2^vi—O4—Pb2^viii	115.37 (5)
O4^vii—Pb2—O4^vi	59.39 (5)	Al5^viii—O4—Pb1	84.88 (6)
O1—Pb2—O2	146.03 (6)	Al4^viii—O4—Pb1	80.74 (6)
O7^vi—Pb2—O2	58.80 (4)	Pb2^vi—O4—Pb1	90.68 (5)
O7^vii—Pb2—O2	58.80 (4)	Sr2^vi—O4—Pb1	90.68 (5)
O4^viii—Pb2—O2	89.41 (5)	Pb2^viii—O4—Pb1	153.38 (5)
O4^ix—Pb2—O2	89.41 (5)	Al1^viii—O5—Al3^xxvii	96.02 (7)
O6^x—Pb2—O2	145.70 (4)	Al1^viii—O5—Al3^viii	96.02 (7)
O6^xi—Pb2—O2	145.70 (4)	Al3^xxvii—O5—Al3^viii	95.28 (9)
O4^vii—Pb2—O2	92.50 (5)	Al1^viii—O5—Sr1^xxiii	156.90 (10)
O4^vi—Pb2—O2	92.50 (5)	Al3^xxvii—O5—Sr1^xxiii	99.48 (6)
O5^xii—Al1—O5^vi	180.0	Al3^viii—O5—Sr1^xxiii	99.48 (6)
O5^xii—Al1—O3^xiii	95.60 (6)	Al1^viii—O5—Pb1^xxiii	156.90 (10)
O5^vi—Al1—O3^xiii	84.40 (6)	Al3^xxvii—O5—Pb1^xxiii	99.48 (6)
O5^xii—Al1—O3^xiv	84.40 (6)	Al3^viii—O5—Pb1^xxiii	99.48 (6)
O5^vi—Al1—O3^xiv	95.60 (6)	Al5^xi—O6—Al2^xxviii	127.55 (7)
O3^xiii—Al1—O3^xiv	180.0	Al5^xi—O6—Al3^xxix	119.36 (7)
O5^xii—Al1—O3^vii	84.40 (6)	Al2^xxviii—O6—Al3^xxix	94.41 (6)
O5^vi—Al1—O3^vii	95.60 (6)	Al5^xi—O6—Pb2^xi	94.48 (6)
O3^xiii—Al1—O3^vii	91.84 (8)	Al2^xxviii—O6—Pb2^xi	89.02 (5)
O3^xiv—Al1—O3^vii	88.16 (8)	Al3^xxix—O6—Pb2^xi	132.22 (6)
O5^xii—Al1—O3^xv	95.60 (6)	Al4^xxiii—O7—Al4^viii	118.72 (9)
O5^vi—Al1—O3^xv	84.40 (6)	Al4^xxiii—O7—Pb2^viii	100.62 (7)
O3^xiii—Al1—O3^xv	88.16 (8)	Al4^viii—O7—Pb2^viii	105.19 (7)
O3^xiv—Al1—O3^xv	91.84 (8)	Al4^xxiii—O7—Sr2^viii	100.62 (7)
O3^vii—Al1—O3^xv	180.0	Al4^viii—O7—Sr2^viii	105.19 (7)
O6^xi—Al2—O6^xvi	180.0	Al4^xxiii—O7—Pb1^xxiii	129.96 (8)
O6^xi—Al2—O6^xvii	86.54 (8)	Al4^viii—O7—Pb1^xxiii	95.99 (7)
O6^xvi—Al2—O6^xvii	93.46 (8)	Pb2^viii—O7—Pb1^xxiii	103.69 (5)
O6^xi—Al2—O6^x	93.46 (8)	Sr2^viii—O7—Pb1^xxiii	103.69 (5)
O6^xvi—Al2—O6^x	86.54 (8)

Symmetry codes: (i) x, y−1, z; (ii) x, y, −z+1; (iii) x, y, z−1; (iv) x, y−1, −z; (v) x, y, −z; (vi) −x+1/2, y−1/2, −z+1/2; (vii) −x+1/2, y−1/2, z−1/2; (viii) −x+1/2, y+1/2, −z+1/2; (ix) −x+1/2, y+1/2, z−1/2; (x) −x+1, −y+1, z−1; (xi) −x+1, −y+1, −z+1; (xii) x−1/2, −y+1/2, z+1/2; (xiii) x−1/2, −y+1/2, z−1/2; (xiv) −x+1/2, y−1/2, −z+3/2; (xv) x−1/2, −y+1/2, −z+3/2; (xvi) x−1, y, z−1; (xvii) x−1, y, −z+1; (xviii) −x, −y+1, −z; (xix) −x+1/2, y+1/2, −z+3/2; (xx) x−1/2, −y+3/2, z+1/2; (xxi) −x+1, −y+1, z; (xxii) x−1, y, z; (xxiii) x, y+1, z; (xxiv) x, y+1, −z; (xxv) −x+1/2, y+1/2, z+1/2; (xxvi) x, y, z+1; (xxvii) x+1/2, −y+3/2, z−1/2; (xxviii) x+1, y, z+1; (xxix) x+1, y, z.