Structure and oxygen mobility in mayenite (Ca₁₂Al₁₄O₃₃): a high-temperature neutron powder diffraction study

The structure of mayenite, Ca₁₂Al₁₄O₃₃, was investigated by neutron powder diffraction up to 1323 K. It has been described previously as a calcium-aluminate framework, in which 32 of the 33 oxygen anions are tightly bound, containing large cages, 1/6 of them being filled randomly by the remaining `free' oxygen. At ambient temperature excess oxygen was found, corresponding to the composition Ca<sub>12</sub>Al<sub>14</sub>O<sub>33.5</sub> which was attributed to the presence of hydroxide, peroxide and superoxide radicals in the cages. Above 973 K these are lost under vacuum conditions and the composition becomes stoichiometric. From the refined structural parameters it is concluded that the structure is more adequately described as a relatively stable aluminate framework consisting of eightfold rings of AlO<sub>4</sub> tetrahedra with disordered Ca and `free' O distributed within. At high temperatures the density of the `free' oxygen is extremely spread out, with the expansion being related to the high ionic conductivity of this material. Since no continuous density distribution between adjacent cages was found and the `free' O forms bonds with part of the Ca, the diffusion proceeds via a jump-like process involving exchange of the `free' oxygen with framework oxygen. The results confirm the recent theoretical predictions of Sushko et al. [(2006), Phys. Rev. B, 73, 014101-1-10].

Computing details

For all compounds, program(s) used to refine structure: (Jana2000; Petricek and Dusek, 2000); software used to prepare material for publication: (Jana2000; Petricek and Dusek, 2000).

(I)

Crystal data

Al14Ca12O33	Z = 2
Mr = 1386.7	F(000) = 1380
Cubic, I43d	Dx = 2.678 Mg m^−3
Hall symbol: I -4bd;2ab;3	Neutron radiation, λ = 1.548 Å
a = 11.9794 Å	µ = 0.001 mm^−1
V = 1719.13 Å^3	T = 298 K

Data collection

Debye Scherrer diffractometer	k = →
h = →	l = →

Refinement

R[F^2 > 2σ(F^2)] = 0.015	45 parameters
wR(F^2) = 0.012	Weighting scheme based on measured s.u.'s
S = 1.68	(Δ/σ)max = 0.018

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

	x	y	z	Uiso*/Ueq	Occ. (<1)
Ca	0.1432 (3)	0	0.25	0.0172 (9)	0.875 (3)
Al1	0.01880 (13)	0.01880 (13)	0.01880 (13)	0.0091 (5)
Al2	0.875	0	0.25	0.0071 (9)
O1	0.78672 (10)	0.09946 (10)	0.30708 (9)	0.0138 (4)
O2	−0.06481 (9)	−0.06481 (9)	−0.06481 (9)	0.0151 (3)
O3	0.375	0	0.25	0.036 (3)*	0.251 (6)
Cas	0.1867 (19)	0	0.25	0.019 (5)*	0.125 (3)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ca	0.032 (2)	0.0082 (12)	0.0111 (12)	0	0	0.0010 (9)
Al1	0.0091 (8)	0.0091 (8)	0.0091 (8)	−0.0003 (7)	−0.0003 (7)	−0.0003 (7)
Al2	0.003 (2)	0.0090 (12)	0.0090 (12)	0	0	0
O1	0.0144 (7)	0.0146 (6)	0.0123 (6)	0.0077 (4)	0.0041 (4)	0.0011 (5)
O2	0.0151 (4)	0.0151 (4)	0.0151 (4)	−0.0023 (5)	−0.0023 (5)	−0.0023 (5)

Geometric parameters (Å, º)

Ca—O1^i	2.3542 (11)	Al2—O1^ix	1.7337 (11)
Ca—O1^ii	2.3542 (11)	Al2—O1^x	1.7337 (11)
Ca—O1^iii	2.556 (3)	O1—O1^viii	2.7476 (16)
Ca—O1^iv	2.556 (3)	O1—O1^ix	2.8719 (16)
Ca—O2^v	2.4037 (13)	O1—O1^x	2.8719 (16)
Ca—O2^vi	2.4037 (13)	O1—O1^xi	2.7474 (16)
Ca—O3	2.777 (3)	O1—O1^xii	2.7474 (16)
Ca—Cas	0.52 (2)	O1—O2^xiii	2.9833 (16)
Al1—O1^i	1.7729 (19)	O1—Cas^xiv	2.392 (4)
Al1—O1^iii	1.7729 (19)	O2—Cas^xv	2.3505 (11)
Al1—O1^vii	1.7729 (19)	O2—Cas^xvi	2.3505 (11)
Al1—O2	1.7348 (19)	O2—Cas^xvii	2.3505 (11)
Al2—O1	1.7337 (11)	O3—Cas	2.26 (2)
Al2—O1^viii	1.7337 (11)	O3—Cas^iii	2.26 (2)
O1^i—Ca—O1^ii	175.71 (15)	O1^ix—O1—O2^xiii	75.54 (4)
O1^i—Ca—O1^iii	67.91 (6)	O1^ix—O1—Cas^xiv	137.2 (3)
O1^i—Ca—O1^iv	116.06 (10)	O1^x—O1—O1^viii	61.42 (4)
O1^i—Ca—O2^v	97.86 (4)	O1^x—O1—O1^ix	57.16 (4)
O1^i—Ca—O2^vi	81.23 (4)	O1^x—O1—O1^xi	139.67 (5)
O1^i—Ca—O3	87.85 (8)	O1^x—O1—O1^xii	160.00 (6)
O1^i—Ca—Cas	87.85 (8)	O1^x—O1—O2^xiii	124.62 (5)
O1^ii—Ca—O1^i	175.71 (15)	O1^x—O1—Cas^xiv	81.2 (3)
O1^ii—Ca—O1^iii	116.06 (10)	O1^xi—O1—O1^viii	155.64 (6)
O1^ii—Ca—O1^iv	67.91 (6)	O1^xi—O1—O1^ix	135.37 (5)
O1^ii—Ca—O2^v	81.23 (4)	O1^xi—O1—O1^x	139.67 (5)
O1^ii—Ca—O2^vi	97.86 (4)	O1^xi—O1—O1^xii	60.00 (4)
O1^ii—Ca—O3	87.85 (8)	O1^xi—O1—O2^xiii	62.58 (4)
O1^ii—Ca—Cas	87.85 (8)	O1^xi—O1—Cas^xiv	71.3 (5)
O1^iii—Ca—O1^i	67.91 (6)	O1^xii—O1—O1^viii	98.62 (5)
O1^iii—Ca—O1^ii	116.06 (10)	O1^xii—O1—O1^ix	113.97 (5)
O1^iii—Ca—O1^iv	65.03 (8)	O1^xii—O1—O1^x	160.00 (6)
O1^iii—Ca—O2^v	125.03 (9)	O1^xii—O1—O1^xi	60.00 (4)
O1^iii—Ca—O2^vi	77.23 (5)	O1^xii—O1—O2^xiii	62.58 (4)
O1^iii—Ca—O3	147.48 (5)	O1^xii—O1—Cas^xiv	108.6 (2)
O1^iii—Ca—Cas	147.48 (5)	O2^xiii—O1—Cas^xiv	130.6 (5)
O1^iv—Ca—O1^i	116.06 (10)	Ca^xv—O2—Ca^xvi	99.93 (8)
O1^iv—Ca—O1^ii	67.91 (6)	Ca^xv—O2—Ca^xvii	99.93 (8)
O1^iv—Ca—O1^iii	65.03 (8)	Ca^xv—O2—Al1	117.86 (8)
O1^iv—Ca—O2^v	77.23 (5)	Ca^xv—O2—O1^i	126.61 (8)
O1^iv—Ca—O2^vi	125.03 (9)	Ca^xv—O2—O1^iii	131.58 (5)
O1^iv—Ca—O3	147.48 (5)	Ca^xv—O2—O1^vii	85.83 (5)
O1^iv—Ca—Cas	147.48 (5)	Ca^xv—O2—Cas^xv	12.5 (6)
O2^v—Ca—O2^vi	155.83 (15)	Ca^xv—O2—Cas^xvi	96.0 (2)
O2^v—Ca—O3	77.91 (8)	Ca^xv—O2—Cas^xvii	112.4 (5)
O2^v—Ca—Cas	77.91 (8)	Ca^xvi—O2—Ca^xv	99.93 (8)
O2^vi—Ca—O2^v	155.83 (15)	Ca^xvi—O2—Ca^xvii	99.93 (8)
O2^vi—Ca—O3	77.91 (8)	Ca^xvi—O2—Al1	117.86 (8)
O2^vi—Ca—Cas	77.91 (8)	Ca^xvi—O2—O1^i	131.58 (5)
O3—Ca—Cas	0	Ca^xvi—O2—O1^iii	85.83 (5)
O1^i—Al1—O1^iii	101.58 (9)	Ca^xvi—O2—O1^vii	126.61 (8)
O1^i—Al1—O1^vii	101.58 (9)	Ca^xvi—O2—Cas^xv	112.4 (5)
O1^i—Al1—O2	116.53 (10)	Ca^xvi—O2—Cas^xvi	12.5 (6)
O1^iii—Al1—O1^i	101.58 (9)	Ca^xvi—O2—Cas^xvii	96.0 (2)
O1^iii—Al1—O1^vii	101.58 (9)	Ca^xvii—O2—Ca^xv	99.93 (8)
O1^iii—Al1—O2	116.53 (10)	Ca^xvii—O2—Ca^xvi	99.93 (8)
O1^vii—Al1—O1^i	101.58 (9)	Ca^xvii—O2—Al1	117.86 (8)
O1^vii—Al1—O1^iii	101.58 (9)	Ca^xvii—O2—O1^i	85.83 (5)
O1^vii—Al1—O2	116.53 (10)	Ca^xvii—O2—O1^iii	126.61 (8)
O1—Al2—O1^viii	104.82 (5)	Ca^xvii—O2—O1^vii	131.58 (5)
O1—Al2—O1^ix	111.84 (5)	Ca^xvii—O2—Cas^xv	96.0 (2)
O1—Al2—O1^x	111.84 (5)	Ca^xvii—O2—Cas^xvi	112.4 (5)
O1^viii—Al2—O1	104.82 (5)	Ca^xvii—O2—Cas^xvii	12.5 (6)
O1^viii—Al2—O1^ix	111.84 (5)	Al1—O2—O1^i	32.12 (6)
O1^viii—Al2—O1^x	111.84 (5)	Al1—O2—O1^iii	32.12 (6)
O1^ix—Al2—O1	111.84 (5)	Al1—O2—O1^vii	32.12 (6)
O1^ix—Al2—O1^viii	111.84 (5)	Al1—O2—Cas^xv	110.5 (3)
O1^ix—Al2—O1^x	104.82 (5)	Al1—O2—Cas^xvi	110.5 (3)
O1^x—Al2—O1	111.84 (5)	Al1—O2—Cas^xvii	110.5 (3)
O1^x—Al2—O1^viii	111.84 (5)	O1^i—O2—O1^iii	54.83 (4)
O1^x—Al2—O1^ix	104.82 (5)	O1^i—O2—O1^vii	54.83 (4)
Ca^xiv—O1—Ca^iii	97.04 (6)	O1^i—O2—Cas^xv	114.7 (5)
Ca^xiv—O1—Al1^xiii	98.66 (10)	O1^i—O2—Cas^xvi	130.81 (10)
Ca^xiv—O1—Al2	121.79 (8)	O1^i—O2—Cas^xvii	79.5 (3)
Ca^xiv—O1—O1^viii	121.40 (9)	O1^iii—O2—O1^i	54.83 (4)
Ca^xiv—O1—O1^ix	141.74 (6)	O1^iii—O2—O1^vii	54.83 (4)
Ca^xiv—O1—O1^x	89.34 (6)	O1^iii—O2—Cas^xv	130.81 (10)
Ca^xiv—O1—O1^xi	59.53 (8)	O1^iii—O2—Cas^xvi	79.5 (3)
Ca^xiv—O1—O1^xii	103.51 (6)	O1^iii—O2—Cas^xvii	114.7 (5)
Ca^xiv—O1—O2^xiii	117.98 (9)	O1^vii—O2—O1^i	54.83 (4)
Ca^xiv—O1—Cas^xiv	12.6 (5)	O1^vii—O2—O1^iii	54.83 (4)
Ca^iii—O1—Ca^xiv	97.04 (6)	O1^vii—O2—Cas^xv	79.5 (3)
Ca^iii—O1—Al1^xiii	91.69 (7)	O1^vii—O2—Cas^xvi	114.7 (5)
Ca^iii—O1—Al2	95.07 (6)	O1^vii—O2—Cas^xvii	130.81 (10)
Ca^iii—O1—O1^viii	57.48 (5)	Cas^xv—O2—Cas^xvi	108.4 (6)
Ca^iii—O1—O1^ix	111.34 (5)	Cas^xv—O2—Cas^xvii	108.4 (6)
Ca^iii—O1—O1^x	111.34 (6)	Cas^xvi—O2—Cas^xv	108.4 (6)
Ca^iii—O1—O1^xi	98.33 (6)	Cas^xvi—O2—Cas^xvii	108.4 (6)
Ca^iii—O1—O1^xii	52.56 (4)	Cas^xvii—O2—Cas^xv	108.4 (6)
Ca^iii—O1—O2^xiii	111.55 (5)	Cas^xvii—O2—Cas^xvi	108.4 (6)
Ca^iii—O1—Cas^xiv	91.1 (3)	Ca—O3—Ca^iii	180
Al1^xiii—O1—Al2	137.61 (8)	Ca—O3—Cas	0
Al1^xiii—O1—O1^viii	130.04 (8)	Ca—O3—Cas^iii	180
Al1^xiii—O1—O1^ix	105.35 (7)	Ca^iii—O3—Ca	180
Al1^xiii—O1—O1^x	154.59 (8)	Ca^iii—O3—Cas	180
Al1^xiii—O1—O1^xi	39.21 (6)	Ca^iii—O3—Cas^iii	0
Al1^xiii—O1—O1^xii	39.21 (6)	Cas—O3—Cas^iii	180
Al1^xiii—O1—O2^xiii	31.35 (6)	Cas^iii—O3—Cas	180
Al1^xiii—O1—Cas^xiv	110.0 (5)	Ca—Cas—O1^i	79.6 (5)
Al2—O1—O1^viii	37.59 (3)	Ca—Cas—O1^ii	79.6 (5)
Al2—O1—O1^ix	34.08 (3)	Ca—Cas—O2^v	89.6 (6)
Al2—O1—O1^x	34.08 (3)	Ca—Cas—O2^vi	89.6 (6)
Al2—O1—O1^xi	166.26 (7)	Ca—Cas—O3	180
Al2—O1—O1^xii	128.08 (6)	O1^i—Cas—O1^ii	159.1 (11)
Al2—O1—O2^xiii	109.42 (5)	O1^i—Cas—O2^v	98.29 (13)
Al2—O1—Cas^xiv	111.6 (4)	O1^i—Cas—O2^vi	81.55 (10)
O1^viii—O1—O1^ix	61.42 (4)	O1^i—Cas—O3	100.4 (5)
O1^viii—O1—O1^x	61.42 (4)	O1^ii—Cas—O1^i	159.1 (11)
O1^viii—O1—O1^xi	155.64 (6)	O1^ii—Cas—O2^v	81.55 (10)
O1^viii—O1—O1^xii	98.62 (5)	O1^ii—Cas—O2^vi	98.29 (13)
O1^viii—O1—O2^xiii	120.42 (5)	O1^ii—Cas—O3	100.4 (5)
O1^viii—O1—Cas^xiv	108.9 (5)	O2^v—Cas—O2^vi	179.1 (11)
O1^ix—O1—O1^viii	61.42 (4)	O2^v—Cas—O3	90.4 (6)
O1^ix—O1—O1^x	57.16 (4)	O2^vi—Cas—O2^v	179.1 (11)
O1^ix—O1—O1^xi	135.37 (5)	O2^vi—Cas—O3	90.4 (6)
O1^ix—O1—O1^xii	113.97 (5)

Symmetry codes: (i) −y+1/4, −x+3/4, z−1/4; (ii) −y+1/4, x−3/4, −z+3/4; (iii) −x+3/4, z−1/4, −y+1/4; (iv) −x+3/4, −z+1/4, y+1/4; (v) y+1/4, −x−1/4, −z+1/4; (vi) y+1/4, x+1/4, z+1/4; (vii) z−1/4, −y+1/4, −x+3/4; (viii) x, −y, −z+1/2; (ix) −x+7/4, z−1/4, −y+1/4; (x) −x+7/4, −z+1/4, y+1/4; (xi) −z+1, x−1/2, −y+1/2; (xii) y+1/2, −z+1/2, −x+1; (xiii) −y+3/4, −x+1/4, z+1/4; (xiv) y+3/4, −x+1/4, −z+3/4; (xv) x−1/4, −z+1/4, −y−1/4; (xvi) −y−1/4, x−1/4, −z+1/4; (xvii) −z+1/4, −y−1/4, x−1/4.

(II)

Crystal data

Al14Ca12O33	Z = 2
Mr = 1386.7	F(000) = 1373
Cubic, I43d	Dx = 2.644 Mg m^−3
Hall symbol: I -4bd;2ab;3	Neutron radiation, λ = 1.548 Å
a = 12.0308 Å	µ = 0.001 mm^−1
V = 1741.32 Å^3	T = 973 K

Data collection

Debye Scherrer diffractometer	k = →
h = →	l = →

Refinement

R[F^2 > 2σ(F^2)] = 0.021	41 parameters
wR(F^2) = 0.015	Weighting scheme based on measured s.u.'s
S = 1.38	(Δ/σ)max = 0.020

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

	x	y	z	Uiso*/Ueq	Occ. (<1)
Ca	0.1464 (4)	0	0.25	0.0342 (15)	0.910 (5)
Al1	0.0176 (2)	0.0176 (2)	0.0176 (2)	0.0183 (7)
Al2	0.875	0	0.25	0.0141 (12)
O1	0.78685 (15)	0.10030 (14)	0.30637 (13)	0.0291 (6)
O2	−0.06453 (13)	−0.06453 (13)	−0.06453 (13)	0.0301 (4)
O3	0.25	0.375	0	0.038 (8)*	0.181 (9)
Cas	0.195 (3)	0	0.25	0.016 (9)*	0.090 (5)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ca	0.041 (3)	0.035 (2)	0.027 (2)	0	0	0.0004 (16)
Al1	0.0183 (12)	0.0183 (12)	0.0183 (12)	−0.0007 (11)	−0.0007 (11)	−0.0007 (11)
Al2	0.005 (3)	0.0187 (16)	0.0187 (16)	0	0	0
O1	0.0334 (11)	0.0268 (10)	0.0270 (10)	0.0194 (8)	0.0131 (8)	0.0041 (8)
O2	0.0301 (7)	0.0301 (7)	0.0301 (7)	−0.0102 (7)	−0.0102 (7)	−0.0102 (7)

Geometric parameters (Å, º)

Ca—O1^i	2.3717 (16)	Al2—O1^x	1.7438 (17)
Ca—O1^ii	2.3717 (16)	Al2—O1^xi	1.7438 (17)
Ca—O1^iii	2.603 (4)	O1—O1^ix	2.768 (2)
Ca—O1^iv	2.603 (4)	O1—O1^x	2.886 (2)
Ca—O2^v	2.4088 (18)	O1—O1^xi	2.886 (2)
Ca—O2^vi	2.4088 (18)	O1—O1^xii	2.749 (2)
Ca—O3^vii	2.750 (5)	O1—O1^xiii	2.749 (2)
Ca—Cas	0.59 (3)	O1—O2^vii	2.978 (2)
Al1—O1^i	1.781 (3)	O1—Cas^xiv	2.434 (8)
Al1—O1^iii	1.781 (3)	O2—Cas^xv	2.365 (2)
Al1—O1^viii	1.781 (3)	O2—Cas^xvi	2.365 (2)
Al1—O2	1.712 (3)	O2—Cas^xvii	2.365 (2)
Al2—O1	1.7438 (17)	O3—Cas^xviii	2.16 (3)
Al2—O1^ix	1.7438 (17)	O3—Cas^xix	2.16 (3)
O1^i—Ca—O1^ii	178.1 (2)	O1^x—O1—O2^vii	75.96 (6)
O1^i—Ca—O1^iii	66.89 (9)	O1^x—O1—Cas^xiv	135.9 (4)
O1^i—Ca—O1^iv	114.89 (15)	O1^xi—O1—O1^ix	61.34 (6)
O1^i—Ca—O2^v	98.06 (6)	O1^xi—O1—O1^x	57.31 (6)
O1^i—Ca—O2^vi	81.56 (6)	O1^xi—O1—O1^xii	139.31 (8)
O1^i—Ca—O3^vii	89.04 (12)	O1^xi—O1—O1^xiii	160.30 (8)
O1^i—Ca—Cas	89.04 (12)	O1^xi—O1—O2^vii	124.92 (8)
O1^ii—Ca—O1^i	178.1 (2)	O1^xi—O1—Cas^xiv	79.1 (5)
O1^ii—Ca—O1^iii	114.89 (15)	O1^xii—O1—O1^ix	155.77 (9)
O1^ii—Ca—O1^iv	66.89 (9)	O1^xii—O1—O1^x	135.73 (8)
O1^ii—Ca—O2^v	81.56 (6)	O1^xii—O1—O1^xi	139.31 (8)
O1^ii—Ca—O2^vi	98.06 (6)	O1^xii—O1—O1^xiii	60.00 (6)
O1^ii—Ca—O3^vii	89.04 (12)	O1^xii—O1—O2^vii	62.52 (6)
O1^ii—Ca—Cas	89.04 (12)	O1^xii—O1—Cas^xiv	73.7 (7)
O1^iii—Ca—O1^i	66.89 (9)	O1^xiii—O1—O1^ix	98.99 (7)
O1^iii—Ca—O1^ii	114.89 (15)	O1^xiii—O1—O1^x	114.10 (7)
O1^iii—Ca—O1^iv	64.25 (12)	O1^xiii—O1—O1^xi	160.30 (8)
O1^iii—Ca—O2^v	123.78 (14)	O1^xiii—O1—O1^xii	60.00 (6)
O1^iii—Ca—O2^vi	76.97 (8)	O1^xiii—O1—O2^vii	62.52 (6)
O1^iii—Ca—O3^vii	147.88 (7)	O1^xiii—O1—Cas^xiv	109.5 (3)
O1^iii—Ca—Cas	147.88 (7)	O2^vii—O1—Cas^xiv	133.1 (8)
O1^iv—Ca—O1^i	114.89 (15)	Ca^xv—O2—Ca^xvi	100.41 (13)
O1^iv—Ca—O1^ii	66.89 (9)	Ca^xv—O2—Ca^xvii	100.41 (13)
O1^iv—Ca—O1^iii	64.25 (12)	Ca^xv—O2—Al1	117.48 (13)
O1^iv—Ca—O2^v	76.97 (8)	Ca^xv—O2—O1^i	125.82 (12)
O1^iv—Ca—O2^vi	123.78 (14)	Ca^xv—O2—O1^iii	131.76 (7)
O1^iv—Ca—O3^vii	147.88 (7)	Ca^xv—O2—O1^viii	85.41 (8)
O1^iv—Ca—Cas	147.88 (7)	Ca^xv—O2—Cas^xv	14.1 (8)
O2^v—Ca—O2^vi	157.5 (2)	Ca^xv—O2—Cas^xvi	96.0 (3)
O2^v—Ca—O3^vii	78.75 (11)	Ca^xv—O2—Cas^xvii	114.5 (8)
O2^v—Ca—Cas	78.75 (11)	Ca^xvi—O2—Ca^xv	100.41 (13)
O2^vi—Ca—O2^v	157.5 (2)	Ca^xvi—O2—Ca^xvii	100.41 (13)
O2^vi—Ca—O3^vii	78.75 (11)	Ca^xvi—O2—Al1	117.48 (13)
O2^vi—Ca—Cas	78.75 (11)	Ca^xvi—O2—O1^i	131.76 (7)
O3^vii—Ca—Cas	0	Ca^xvi—O2—O1^iii	85.41 (8)
O1^i—Al1—O1^iii	101.03 (14)	Ca^xvi—O2—O1^viii	125.82 (12)
O1^i—Al1—O1^viii	101.03 (14)	Ca^xvi—O2—Cas^xv	114.5 (8)
O1^i—Al1—O2	116.97 (16)	Ca^xvi—O2—Cas^xvi	14.1 (8)
O1^iii—Al1—O1^i	101.03 (14)	Ca^xvi—O2—Cas^xvii	96.0 (3)
O1^iii—Al1—O1^viii	101.03 (14)	Ca^xvii—O2—Ca^xv	100.41 (13)
O1^iii—Al1—O2	116.97 (16)	Ca^xvii—O2—Ca^xvi	100.41 (13)
O1^viii—Al1—O1^i	101.03 (14)	Ca^xvii—O2—Al1	117.48 (13)
O1^viii—Al1—O1^iii	101.03 (14)	Ca^xvii—O2—O1^i	85.41 (8)
O1^viii—Al1—O2	116.97 (16)	Ca^xvii—O2—O1^iii	125.82 (12)
O1—Al2—O1^ix	105.08 (8)	Ca^xvii—O2—O1^viii	131.76 (7)
O1—Al2—O1^x	111.71 (8)	Ca^xvii—O2—Cas^xv	96.0 (3)
O1—Al2—O1^xi	111.71 (8)	Ca^xvii—O2—Cas^xvi	114.5 (8)
O1^ix—Al2—O1	105.08 (8)	Ca^xvii—O2—Cas^xvii	14.1 (8)
O1^ix—Al2—O1^x	111.71 (8)	Al1—O2—O1^i	32.20 (9)
O1^ix—Al2—O1^xi	111.71 (8)	Al1—O2—O1^iii	32.20 (9)
O1^x—Al2—O1	111.71 (8)	Al1—O2—O1^viii	32.20 (9)
O1^x—Al2—O1^ix	111.71 (8)	Al1—O2—Cas^xv	109.0 (5)
O1^x—Al2—O1^xi	105.08 (8)	Al1—O2—Cas^xvi	109.0 (5)
O1^xi—Al2—O1	111.71 (8)	Al1—O2—Cas^xvii	109.0 (5)
O1^xi—Al2—O1^ix	111.71 (8)	O1^i—O2—O1^iii	54.96 (5)
O1^xi—Al2—O1^x	105.08 (8)	O1^i—O2—O1^viii	54.96 (5)
Ca^xiv—O1—Ca^iii	96.05 (8)	O1^i—O2—Cas^xv	112.4 (8)
Ca^xiv—O1—Al1^vii	99.98 (15)	O1^i—O2—Cas^xvi	130.58 (17)
Ca^xiv—O1—Al2	120.48 (12)	O1^i—O2—Cas^xvii	78.3 (4)
Ca^xiv—O1—O1^ix	119.72 (13)	O1^iii—O2—O1^i	54.96 (5)
Ca^xiv—O1—O1^x	141.43 (8)	O1^iii—O2—O1^viii	54.96 (5)
Ca^xiv—O1—O1^xi	88.19 (9)	O1^iii—O2—Cas^xv	130.58 (17)
Ca^xiv—O1—O1^xii	60.58 (12)	O1^iii—O2—Cas^xvi	78.3 (4)
Ca^xiv—O1—O1^xiii	103.96 (9)	O1^iii—O2—Cas^xvii	112.4 (8)
Ca^xiv—O1—O2^vii	119.09 (13)	O1^viii—O2—O1^i	54.96 (5)
Ca^xiv—O1—Cas^xiv	14.0 (8)	O1^viii—O2—O1^iii	54.96 (5)
Ca^iii—O1—Ca^xiv	96.05 (8)	O1^viii—O2—Cas^xv	78.3 (4)
Ca^iii—O1—Al1^vii	91.93 (11)	O1^viii—O2—Cas^xvi	112.4 (8)
Ca^iii—O1—Al2	95.33 (9)	O1^viii—O2—Cas^xvii	130.58 (17)
Ca^iii—O1—O1^ix	57.88 (7)	Cas^xv—O2—Cas^xvi	109.9 (9)
Ca^iii—O1—O1^x	111.55 (8)	Cas^xv—O2—Cas^xvii	109.9 (9)
Ca^iii—O1—O1^xi	111.55 (8)	Cas^xvi—O2—Cas^xv	109.9 (9)
Ca^iii—O1—O1^xii	98.01 (9)	Cas^xvi—O2—Cas^xvii	109.9 (9)
Ca^iii—O1—O1^xiii	52.52 (6)	Cas^xvii—O2—Cas^xv	109.9 (9)
Ca^iii—O1—O2^vii	111.63 (7)	Cas^xvii—O2—Cas^xvi	109.9 (9)
Ca^iii—O1—Cas^xiv	89.5 (4)	Ca^xviii—O3—Ca^xix	180
Al1^vii—O1—Al2	137.69 (13)	Ca^xviii—O3—Cas^xviii	0
Al1^vii—O1—O1^ix	130.51 (12)	Ca^xviii—O3—Cas^xix	180
Al1^vii—O1—O1^x	105.25 (11)	Ca^xix—O3—Ca^xviii	180
Al1^vii—O1—O1^xi	154.30 (12)	Ca^xix—O3—Cas^xviii	180
Al1^vii—O1—O1^xii	39.48 (9)	Ca^xix—O3—Cas^xix	0
Al1^vii—O1—O1^xiii	39.48 (9)	Cas^xviii—O3—Cas^xix	180
Al1^vii—O1—O2^vii	30.83 (9)	Cas^xix—O3—Cas^xviii	180
Al1^vii—O1—Cas^xiv	112.6 (7)	Ca—Cas—O1^i	77.0 (8)
Al2—O1—O1^ix	37.46 (5)	Ca—Cas—O1^ii	77.0 (8)
Al2—O1—O1^x	34.15 (5)	Ca—Cas—O2^v	87.1 (8)
Al2—O1—O1^xi	34.15 (5)	Ca—Cas—O2^vi	87.1 (8)
Al2—O1—O1^xii	166.41 (10)	Ca—Cas—O3^vii	180
Al2—O1—O1^xiii	128.36 (9)	O1^i—Cas—O1^ii	154.0 (16)
Al2—O1—O2^vii	109.93 (8)	O1^i—Cas—O2^v	97.5 (3)
Al2—O1—Cas^xiv	109.1 (7)	O1^i—Cas—O2^vi	81.2 (2)
O1^ix—O1—O1^x	61.34 (6)	O1^i—Cas—O3^vii	103.0 (8)
O1^ix—O1—O1^xi	61.34 (6)	O1^ii—Cas—O1^i	154.0 (16)
O1^ix—O1—O1^xii	155.77 (9)	O1^ii—Cas—O2^v	81.2 (2)
O1^ix—O1—O1^xiii	98.99 (7)	O1^ii—Cas—O2^vi	97.5 (3)
O1^ix—O1—O2^vii	121.01 (7)	O1^ii—Cas—O3^vii	103.0 (8)
O1^ix—O1—Cas^xiv	105.8 (8)	O2^v—Cas—O2^vi	174.3 (17)
O1^x—O1—O1^ix	61.34 (6)	O2^v—Cas—O3^vii	92.9 (8)
O1^x—O1—O1^xi	57.31 (6)	O2^vi—Cas—O2^v	174.3 (17)
O1^x—O1—O1^xii	135.73 (8)	O2^vi—Cas—O3^vii	92.9 (8)
O1^x—O1—O1^xiii	114.10 (7)

Symmetry codes: (i) −y+1/4, −x+3/4, z−1/4; (ii) −y+1/4, x−3/4, −z+3/4; (iii) −x+3/4, z−1/4, −y+1/4; (iv) −x+3/4, −z+1/4, y+1/4; (v) y+1/4, −x−1/4, −z+1/4; (vi) y+1/4, x+1/4, z+1/4; (vii) −y+3/4, −x+1/4, z+1/4; (viii) z−1/4, −y+1/4, −x+3/4; (ix) x, −y, −z+1/2; (x) −x+7/4, z−1/4, −y+1/4; (xi) −x+7/4, −z+1/4, y+1/4; (xii) −z+1, x−1/2, −y+1/2; (xiii) y+1/2, −z+1/2, −x+1; (xiv) y+3/4, −x+1/4, −z+3/4; (xv) x−1/4, −z+1/4, −y−1/4; (xvi) −y−1/4, x−1/4, −z+1/4; (xvii) −z+1/4, −y−1/4, x−1/4; (xviii) y+1/4, −x+3/4, −z+1/4; (xix) z, x, y.

(III)

Crystal data

Al14Ca12O33	Z = 2
Mr = 1386.7	F(000) = 1367
Cubic, I43d	Dx = 2.635 Mg m^−3
Hall symbol: I -4bd;2ab;3	Neutron radiation, λ = 1.548 Å
a = 12.0449 Å	µ = 0.001 mm^−1
V = 1747.46 Å^3	T = 1223 K

Data collection

Debye Scherrer diffractometer	k = →
h = →	l = →

Refinement

R[F^2 > 2σ(F^2)] = 0.027	42 parameters
wR(F^2) = 0.017	Weighting scheme based on measured s.u.'s
S = 1.59	(Δ/σ)max = 0.041

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

	x	y	z	Uiso*/Ueq	Occ. (<1)
Ca	0.1452 (4)	0	0.25	0.0410 (15)	0.942 (7)
Al1	0.0185 (2)	0.0185 (2)	0.0185 (2)	0.0200 (7)
Al2	0.875	0	0.25	0.0219 (13)
O1	0.78787 (15)	0.10043 (14)	0.30624 (14)	0.0363 (7)
O2	−0.06386 (13)	−0.06386 (13)	−0.06386 (13)	0.0375 (5)
O3	0.375	0	0.25	0.14 (4)*	0.116 (15)
Cas	0.211 (5)	0	0.25	0.017 (13)*	0.058 (7)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ca	0.054 (3)	0.039 (2)	0.030 (2)	0	0	−0.0002 (17)
Al1	0.0200 (13)	0.0200 (13)	0.0200 (13)	−0.0024 (11)	−0.0024 (11)	−0.0024 (11)
Al2	0.018 (3)	0.0241 (17)	0.0241 (17)	0	0	0
O1	0.0400 (13)	0.0332 (11)	0.0357 (11)	0.0239 (9)	0.0146 (9)	0.0037 (9)
O2	0.0375 (8)	0.0375 (8)	0.0375 (8)	−0.0109 (8)	−0.0109 (8)	−0.0109 (8)

Geometric parameters (Å, º)

Ca—O1^i	2.3785 (17)	Al2—O1^ix	1.7389 (17)
Ca—O1^ii	2.3785 (17)	Al2—O1^x	1.7389 (17)
Ca—O1^iii	2.605 (5)	O1—O1^viii	2.773 (2)
Ca—O1^iv	2.605 (5)	O1—O1^ix	2.872 (2)
Ca—O2^v	2.4210 (19)	O1—O1^x	2.872 (2)
Ca—O2^vi	2.4210 (19)	O1—O1^xi	2.765 (2)
Ca—O3	2.768 (5)	O1—O1^xii	2.765 (2)
Ca—Cas	0.79 (6)	O1—O2^xiii	2.966 (2)
Al1—O1^i	1.778 (3)	O1—Cas^xiv	2.489 (16)
Al1—O1^iii	1.778 (3)	O2—Cas^xv	2.388 (7)
Al1—O1^vii	1.778 (3)	O2—Cas^xvi	2.388 (7)
Al1—O2	1.718 (3)	O2—Cas^xvii	2.388 (7)
Al2—O1	1.7389 (17)	O3—Cas	1.98 (6)
Al2—O1^viii	1.7389 (17)	O3—Cas^iii	1.98 (6)
O1^i—Ca—O1^ii	177.5 (2)	O1^ix—O1—O2^xiii	76.29 (6)
O1^i—Ca—O1^iii	67.22 (9)	O1^ix—O1—Cas^xiv	134.1 (7)
O1^i—Ca—O1^iv	115.11 (16)	O1^x—O1—O1^viii	61.14 (6)
O1^i—Ca—O2^v	97.45 (7)	O1^x—O1—O1^ix	57.72 (6)
O1^i—Ca—O2^vi	82.03 (6)	O1^x—O1—O1^xi	139.52 (8)
O1^i—Ca—O3	88.74 (13)	O1^x—O1—O1^xii	160.01 (8)
O1^i—Ca—Cas	88.74 (13)	O1^x—O1—O2^xiii	125.63 (8)
O1^ii—Ca—O1^i	177.5 (2)	O1^x—O1—Cas^xiv	76.5 (8)
O1^ii—Ca—O1^iii	115.11 (16)	O1^xi—O1—O1^viii	155.65 (9)
O1^ii—Ca—O1^iv	67.22 (9)	O1^xi—O1—O1^ix	135.89 (8)
O1^ii—Ca—O2^v	82.03 (6)	O1^xi—O1—O1^x	139.52 (8)
O1^ii—Ca—O2^vi	97.45 (7)	O1^xi—O1—O1^xii	60.00 (6)
O1^ii—Ca—O3	88.74 (13)	O1^xi—O1—O2^xiii	62.22 (6)
O1^ii—Ca—Cas	88.74 (13)	O1^xi—O1—Cas^xiv	77.6 (11)
O1^iii—Ca—O1^i	67.22 (9)	O1^xii—O1—O1^viii	98.88 (7)
O1^iii—Ca—O1^ii	115.11 (16)	O1^xii—O1—O1^ix	113.75 (8)
O1^iii—Ca—O1^iv	64.32 (13)	O1^xii—O1—O1^x	160.01 (8)
O1^iii—Ca—O2^v	124.11 (15)	O1^xii—O1—O1^xi	60.00 (6)
O1^iii—Ca—O2^vi	77.52 (8)	O1^xii—O1—O2^xiii	62.22 (6)
O1^iii—Ca—O3	147.84 (7)	O1^xii—O1—Cas^xiv	110.8 (4)
O1^iii—Ca—Cas	147.84 (7)	O2^xiii—O1—Cas^xiv	137.1 (12)
O1^iv—Ca—O1^i	115.11 (16)	Ca^xv—O2—Ca^xvi	99.81 (13)
O1^iv—Ca—O1^ii	67.22 (9)	Ca^xv—O2—Ca^xvii	99.81 (13)
O1^iv—Ca—O1^iii	64.32 (13)	Ca^xv—O2—Al1	117.95 (13)
O1^iv—Ca—O2^v	77.52 (8)	Ca^xv—O2—O1^i	126.48 (13)
O1^iv—Ca—O2^vi	124.11 (15)	Ca^xv—O2—O1^iii	132.00 (7)
O1^iv—Ca—O3	147.84 (7)	Ca^xv—O2—O1^vii	85.51 (8)
O1^iv—Ca—Cas	147.84 (7)	Ca^xv—O2—Cas^xv	18.8 (13)
O2^v—Ca—O2^vi	156.5 (2)	Ca^xv—O2—Cas^xvi	93.9 (5)
O2^v—Ca—O3	78.25 (12)	Ca^xv—O2—Cas^xvii	118.5 (13)
O2^v—Ca—Cas	78.25 (12)	Ca^xvi—O2—Ca^xv	99.81 (13)
O2^vi—Ca—O2^v	156.5 (2)	Ca^xvi—O2—Ca^xvii	99.81 (13)
O2^vi—Ca—O3	78.25 (12)	Ca^xvi—O2—Al1	117.95 (13)
O2^vi—Ca—Cas	78.25 (12)	Ca^xvi—O2—O1^i	132.00 (7)
O3—Ca—Cas	0	Ca^xvi—O2—O1^iii	85.51 (8)
O1^i—Al1—O1^iii	102.09 (15)	Ca^xvi—O2—O1^vii	126.48 (13)
O1^i—Al1—O1^vii	102.09 (15)	Ca^xvi—O2—Cas^xv	118.5 (13)
O1^i—Al1—O2	116.11 (16)	Ca^xvi—O2—Cas^xvi	18.8 (13)
O1^iii—Al1—O1^i	102.09 (15)	Ca^xvi—O2—Cas^xvii	93.9 (5)
O1^iii—Al1—O1^vii	102.09 (15)	Ca^xvii—O2—Ca^xv	99.81 (13)
O1^iii—Al1—O2	116.11 (16)	Ca^xvii—O2—Ca^xvi	99.81 (13)
O1^vii—Al1—O1^i	102.09 (15)	Ca^xvii—O2—Al1	117.95 (13)
O1^vii—Al1—O1^iii	102.09 (15)	Ca^xvii—O2—O1^i	85.51 (8)
O1^vii—Al1—O2	116.11 (16)	Ca^xvii—O2—O1^iii	126.48 (13)
O1—Al2—O1^viii	105.75 (8)	Ca^xvii—O2—O1^vii	132.00 (7)
O1—Al2—O1^ix	111.36 (8)	Ca^xvii—O2—Cas^xv	93.9 (5)
O1—Al2—O1^x	111.36 (8)	Ca^xvii—O2—Cas^xvi	118.5 (13)
O1^viii—Al2—O1	105.75 (8)	Ca^xvii—O2—Cas^xvii	18.8 (13)
O1^viii—Al2—O1^ix	111.36 (8)	Al1—O2—O1^i	32.56 (10)
O1^viii—Al2—O1^x	111.36 (8)	Al1—O2—O1^iii	32.56 (10)
O1^ix—Al2—O1	111.36 (8)	Al1—O2—O1^vii	32.56 (10)
O1^ix—Al2—O1^viii	111.36 (8)	Al1—O2—Cas^xv	106.6 (9)
O1^ix—Al2—O1^x	105.75 (8)	Al1—O2—Cas^xvi	106.6 (9)
O1^x—Al2—O1	111.36 (8)	Al1—O2—Cas^xvii	106.6 (9)
O1^x—Al2—O1^viii	111.36 (8)	O1^i—O2—O1^iii	55.56 (6)
O1^x—Al2—O1^ix	105.75 (8)	O1^i—O2—O1^vii	55.56 (6)
Ca^xiv—O1—Ca^iii	95.91 (9)	O1^i—O2—Cas^xv	108.5 (13)
Ca^xiv—O1—Al1^xiii	99.11 (15)	O1^i—O2—Cas^xvi	130.1 (3)
Ca^xiv—O1—Al2	120.88 (13)	O1^i—O2—Cas^xvii	76.1 (6)
Ca^xiv—O1—O1^viii	119.91 (14)	O1^iii—O2—O1^i	55.56 (6)
Ca^xiv—O1—O1^ix	142.08 (9)	O1^iii—O2—O1^vii	55.56 (6)
Ca^xiv—O1—O1^x	88.44 (10)	O1^iii—O2—Cas^xv	130.1 (3)
Ca^xiv—O1—O1^xi	60.30 (12)	O1^iii—O2—Cas^xvi	76.1 (6)
Ca^xiv—O1—O1^xii	103.69 (9)	O1^iii—O2—Cas^xvii	108.5 (13)
Ca^xiv—O1—O2^xiii	118.66 (14)	O1^vii—O2—O1^i	55.56 (6)
Ca^xiv—O1—Cas^xiv	18.4 (12)	O1^vii—O2—O1^iii	55.56 (6)
Ca^iii—O1—Ca^xiv	95.91 (9)	O1^vii—O2—Cas^xv	76.1 (6)
Ca^iii—O1—Al1^xiii	91.30 (12)	O1^vii—O2—Cas^xvi	108.5 (13)
Ca^iii—O1—Al2	94.97 (9)	O1^vii—O2—Cas^xvii	130.1 (3)
Ca^iii—O1—O1^viii	57.84 (8)	Cas^xv—O2—Cas^xvi	112.2 (14)
Ca^iii—O1—O1^ix	111.21 (8)	Cas^xv—O2—Cas^xvii	112.2 (14)
Ca^iii—O1—O1^x	111.21 (8)	Cas^xvi—O2—Cas^xv	112.2 (14)
Ca^iii—O1—O1^xi	97.92 (9)	Cas^xvi—O2—Cas^xvii	112.2 (14)
Ca^iii—O1—O1^xii	52.48 (6)	Cas^xvii—O2—Cas^xv	112.2 (14)
Ca^iii—O1—O2^xiii	111.41 (7)	Cas^xvii—O2—Cas^xvi	112.2 (14)
Ca^iii—O1—Cas^xiv	87.2 (6)	Ca—O3—Ca^iii	180
Al1^xiii—O1—Al2	138.47 (13)	Ca—O3—Cas	0
Al1^xiii—O1—O1^viii	130.53 (12)	Ca—O3—Cas^iii	180
Al1^xiii—O1—O1^ix	105.99 (11)	Ca^iii—O3—Ca	180
Al1^xiii—O1—O1^x	155.49 (13)	Ca^iii—O3—Cas	180
Al1^xiii—O1—O1^xi	38.95 (10)	Ca^iii—O3—Cas^iii	0
Al1^xiii—O1—O1^xii	38.95 (10)	Cas—O3—Cas^iii	180
Al1^xiii—O1—O2^xiii	31.33 (9)	Cas^iii—O3—Cas	180
Al1^xiii—O1—Cas^xiv	115.6 (11)	Ca—Cas—O1^i	72.8 (12)
Al2—O1—O1^viii	37.12 (5)	Ca—Cas—O1^ii	72.8 (12)
Al2—O1—O1^ix	34.32 (5)	Ca—Cas—O2^v	82.9 (13)
Al2—O1—O1^x	34.32 (5)	Ca—Cas—O2^vi	82.9 (13)
Al2—O1—O1^xi	166.86 (10)	Ca—Cas—O3	180
Al2—O1—O1^xii	128.02 (9)	O1^i—Cas—O1^ii	146 (2)
Al2—O1—O2^xiii	110.44 (8)	O1^i—Cas—O2^v	95.4 (6)
Al2—O1—Cas^xiv	105.7 (10)	O1^i—Cas—O2^vi	80.4 (5)
O1^viii—O1—O1^ix	61.14 (6)	O1^i—Cas—O3	107.2 (12)
O1^viii—O1—O1^x	61.14 (6)	O1^ii—Cas—O1^i	146 (2)
O1^viii—O1—O1^xi	155.65 (9)	O1^ii—Cas—O2^v	80.4 (5)
O1^viii—O1—O1^xii	98.88 (7)	O1^ii—Cas—O2^vi	95.4 (6)
O1^viii—O1—O2^xiii	121.19 (7)	O1^ii—Cas—O3	107.2 (12)
O1^viii—O1—Cas^xiv	101.6 (12)	O2^v—Cas—O2^vi	166 (3)
O1^ix—O1—O1^viii	61.14 (6)	O2^v—Cas—O3	97.1 (13)
O1^ix—O1—O1^x	57.72 (6)	O2^vi—Cas—O2^v	166 (3)
O1^ix—O1—O1^xi	135.89 (8)	O2^vi—Cas—O3	97.1 (13)
O1^ix—O1—O1^xii	113.75 (8)

Symmetry codes: (i) −y+1/4, −x+3/4, z−1/4; (ii) −y+1/4, x−3/4, −z+3/4; (iii) −x+3/4, z−1/4, −y+1/4; (iv) −x+3/4, −z+1/4, y+1/4; (v) y+1/4, −x−1/4, −z+1/4; (vi) y+1/4, x+1/4, z+1/4; (vii) z−1/4, −y+1/4, −x+3/4; (viii) x, −y, −z+1/2; (ix) −x+7/4, z−1/4, −y+1/4; (x) −x+7/4, −z+1/4, y+1/4; (xi) −z+1, x−1/2, −y+1/2; (xii) y+1/2, −z+1/2, −x+1; (xiii) −y+3/4, −x+1/4, z+1/4; (xiv) y+3/4, −x+1/4, −z+3/4; (xv) x−1/4, −z+1/4, −y−1/4; (xvi) −y−1/4, x−1/4, −z+1/4; (xvii) −z+1/4, −y−1/4, x−1/4.

(IV)

Crystal data

Al14Ca12O33	Z = 2
Mr = 1386.7	F(000) = 1370
Cubic, I43d	Dx = 2.626 Mg m^−3
Hall symbol: I -4bd;2ab;3	Neutron radiation, λ = 1.548 Å
a = 12.0585 Å	µ = 0.001 mm^−1
V = 1753.40 Å^3	T = 1323 K

Data collection

Debye Scherrer diffractometer	k = →
h = →	l = →

Refinement

R[F^2 > 2σ(F^2)] = 0.031	41 parameters
wR(F^2) = 0.022	Weighting scheme based on measured s.u.'s
S = 1.43	(Δ/σ)max = 0.017

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

	x	y	z	Uiso*/Ueq	Occ. (<1)
Ca	0.1456 (6)	0	0.25	0.047 (2)	0.926 (13)
Al1	0.0183 (3)	0.0183 (3)	0.0183 (3)	0.0253 (9)
Al2	0.875	0	0.25	0.0199 (14)
O1	0.78779 (18)	0.10087 (16)	0.30547 (16)	0.0430 (9)
O2	−0.06399 (16)	−0.06399 (16)	−0.06399 (16)	0.0428 (6)
O3	0.375	0	0.25	0.28 (7)*	0.15 (3)
Cas	0.212 (7)	0	0.25	0.05 (2)*	0.074 (13)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ca	0.066 (5)	0.041 (3)	0.034 (3)	0	0	0.000 (2)
Al1	0.0253 (16)	0.0253 (16)	0.0253 (16)	−0.0035 (13)	−0.0035 (13)	−0.0035 (13)
Al2	0.014 (3)	0.0231 (18)	0.0231 (18)	0	0	0
O1	0.0514 (17)	0.0398 (14)	0.0379 (13)	0.0291 (11)	0.0149 (11)	0.0031 (11)
O2	0.0428 (11)	0.0428 (11)	0.0428 (11)	−0.0119 (10)	−0.0119 (10)	−0.0119 (10)

Geometric parameters (Å, º)

Ca—O1^i	2.3900 (19)	Al2—O1^ix	1.742 (2)
Ca—O1^ii	2.3900 (19)	Al2—O1^x	1.742 (2)
Ca—O1^iii	2.611 (6)	O1—O1^viii	2.776 (3)
Ca—O1^iv	2.611 (6)	O1—O1^ix	2.877 (3)
Ca—O2^v	2.421 (2)	O1—O1^x	2.877 (3)
Ca—O2^vi	2.421 (2)	O1—O1^xi	2.761 (3)
Ca—O3	2.766 (7)	O1—O1^xii	2.761 (3)
Ca—Cas	0.81 (9)	O1—O2^xiii	2.963 (3)
Al1—O1^i	1.774 (4)	O1—Cas^xiv	2.51 (3)
Al1—O1^iii	1.774 (4)	O2—Cas^xv	2.393 (12)
Al1—O1^vii	1.774 (4)	O2—Cas^xvi	2.393 (12)
Al1—O2	1.718 (4)	O2—Cas^xvii	2.393 (12)
Al2—O1	1.742 (2)	O3—Cas	1.96 (9)
Al2—O1^viii	1.742 (2)	O3—Cas^iii	1.96 (9)
O1^i—Ca—O1^ii	178.0 (3)	O1^ix—O1—O2^xiii	76.62 (7)
O1^i—Ca—O1^iii	66.83 (12)	O1^ix—O1—Cas^xiv	133.4 (11)
O1^i—Ca—O1^iv	115.0 (2)	O1^x—O1—O1^viii	61.15 (7)
O1^i—Ca—O2^v	97.62 (8)	O1^x—O1—O1^ix	57.69 (7)
O1^i—Ca—O2^vi	81.97 (8)	O1^x—O1—O1^xi	139.02 (9)
O1^i—Ca—O3	88.99 (17)	O1^x—O1—O1^xii	160.47 (10)
O1^i—Ca—Cas	88.99 (17)	O1^x—O1—O2^xiii	125.66 (9)
O1^ii—Ca—O1^i	178.0 (3)	O1^x—O1—Cas^xiv	75.9 (12)
O1^ii—Ca—O1^iii	115.0 (2)	O1^xi—O1—O1^viii	155.87 (11)
O1^ii—Ca—O1^iv	66.83 (12)	O1^xi—O1—O1^ix	136.16 (9)
O1^ii—Ca—O2^v	81.97 (8)	O1^xi—O1—O1^x	139.02 (9)
O1^ii—Ca—O2^vi	97.62 (8)	O1^xi—O1—O1^xii	60.00 (7)
O1^ii—Ca—O3	88.99 (17)	O1^xi—O1—O2^xiii	62.23 (7)
O1^ii—Ca—Cas	88.99 (17)	O1^xi—O1—Cas^xiv	78.0 (18)
O1^iii—Ca—O1^i	66.83 (12)	O1^xii—O1—O1^viii	99.33 (9)
O1^iii—Ca—O1^ii	115.0 (2)	O1^xii—O1—O1^ix	114.07 (9)
O1^iii—Ca—O1^iv	64.22 (18)	O1^xii—O1—O1^x	160.47 (10)
O1^iii—Ca—O2^v	123.8 (2)	O1^xii—O1—O1^xi	60.00 (7)
O1^iii—Ca—O2^vi	77.56 (11)	O1^xii—O1—O2^xiii	62.23 (7)
O1^iii—Ca—O3	147.89 (9)	O1^xii—O1—Cas^xiv	110.9 (7)
O1^iii—Ca—Cas	147.89 (9)	O2^xiii—O1—Cas^xiv	137.5 (19)
O1^iv—Ca—O1^i	115.0 (2)	Ca^xv—O2—Ca^xvi	99.96 (18)
O1^iv—Ca—O1^ii	66.83 (12)	Ca^xv—O2—Ca^xvii	99.96 (18)
O1^iv—Ca—O1^iii	64.22 (18)	Ca^xv—O2—Al1	117.83 (16)
O1^iv—Ca—O2^v	77.56 (11)	Ca^xv—O2—O1^i	126.21 (17)
O1^iv—Ca—O2^vi	123.8 (2)	Ca^xv—O2—O1^iii	132.06 (8)
O1^iv—Ca—O3	147.89 (9)	Ca^xv—O2—O1^vii	85.42 (11)
O1^iv—Ca—Cas	147.89 (9)	Ca^xv—O2—Cas^xv	19 (2)
O2^v—Ca—O2^vi	156.8 (3)	Ca^xv—O2—Cas^xvi	93.9 (7)
O2^v—Ca—O3	78.40 (17)	Ca^xv—O2—Cas^xvii	119 (2)
O2^v—Ca—Cas	78.40 (17)	Ca^xvi—O2—Ca^xv	99.96 (18)
O2^vi—Ca—O2^v	156.8 (3)	Ca^xvi—O2—Ca^xvii	99.96 (18)
O2^vi—Ca—O3	78.40 (17)	Ca^xvi—O2—Al1	117.83 (16)
O2^vi—Ca—Cas	78.40 (17)	Ca^xvi—O2—O1^i	132.06 (8)
O3—Ca—Cas	0	Ca^xvi—O2—O1^iii	85.42 (11)
O1^i—Al1—O1^iii	102.15 (18)	Ca^xvi—O2—O1^vii	126.21 (17)
O1^i—Al1—O1^vii	102.15 (18)	Ca^xvi—O2—Cas^xv	119 (2)
O1^i—Al1—O2	116.06 (19)	Ca^xvi—O2—Cas^xvi	19 (2)
O1^iii—Al1—O1^i	102.15 (18)	Ca^xvi—O2—Cas^xvii	93.9 (7)
O1^iii—Al1—O1^vii	102.15 (18)	Ca^xvii—O2—Ca^xv	99.96 (18)
O1^iii—Al1—O2	116.06 (19)	Ca^xvii—O2—Ca^xvi	99.96 (18)
O1^vii—Al1—O1^i	102.15 (18)	Ca^xvii—O2—Al1	117.83 (16)
O1^vii—Al1—O1^iii	102.15 (18)	Ca^xvii—O2—O1^i	85.42 (11)
O1^vii—Al1—O2	116.06 (19)	Ca^xvii—O2—O1^iii	126.21 (17)
O1—Al2—O1^viii	105.71 (10)	Ca^xvii—O2—O1^vii	132.06 (8)
O1—Al2—O1^ix	111.39 (9)	Ca^xvii—O2—Cas^xv	93.9 (7)
O1—Al2—O1^x	111.39 (9)	Ca^xvii—O2—Cas^xvi	119 (2)
O1^viii—Al2—O1	105.71 (10)	Ca^xvii—O2—Cas^xvii	19 (2)
O1^viii—Al2—O1^ix	111.39 (9)	Al1—O2—O1^i	32.54 (12)
O1^viii—Al2—O1^x	111.39 (9)	Al1—O2—O1^iii	32.54 (12)
O1^ix—Al2—O1	111.39 (9)	Al1—O2—O1^vii	32.54 (12)
O1^ix—Al2—O1^viii	111.39 (9)	Al1—O2—Cas^xv	106.2 (14)
O1^ix—Al2—O1^x	105.71 (10)	Al1—O2—Cas^xvi	106.2 (14)
O1^x—Al2—O1	111.39 (9)	Al1—O2—Cas^xvii	106.2 (14)
O1^x—Al2—O1^viii	111.39 (9)	O1^i—O2—O1^iii	55.53 (7)
O1^x—Al2—O1^ix	105.71 (10)	O1^i—O2—O1^vii	55.53 (7)
Ca^xiv—O1—Ca^iii	95.63 (11)	O1^i—O2—Cas^xv	108 (2)
Ca^xiv—O1—Al1^xiii	99.2 (2)	O1^i—O2—Cas^xvi	129.9 (5)
Ca^xiv—O1—Al2	120.29 (17)	O1^i—O2—Cas^xvii	75.9 (10)
Ca^xiv—O1—O1^viii	119.23 (19)	O1^iii—O2—O1^i	55.53 (7)
Ca^xiv—O1—O1^ix	141.80 (11)	O1^iii—O2—O1^vii	55.53 (7)
Ca^xiv—O1—O1^x	87.95 (13)	O1^iii—O2—Cas^xv	129.9 (5)
Ca^xiv—O1—O1^xi	60.42 (17)	O1^iii—O2—Cas^xvi	75.9 (10)
Ca^xiv—O1—O1^xii	103.71 (11)	O1^iii—O2—Cas^xvii	108 (2)
Ca^xiv—O1—O2^xiii	118.83 (19)	O1^vii—O2—O1^i	55.53 (7)
Ca^xiv—O1—Cas^xiv	19 (2)	O1^vii—O2—O1^iii	55.53 (7)
Ca^iii—O1—Ca^xiv	95.63 (11)	O1^vii—O2—Cas^xv	75.9 (10)
Ca^iii—O1—Al1^xiii	91.53 (14)	O1^vii—O2—Cas^xvi	108 (2)
Ca^iii—O1—Al2	95.04 (12)	O1^vii—O2—Cas^xvii	129.9 (5)
Ca^iii—O1—O1^viii	57.89 (10)	Cas^xv—O2—Cas^xvi	113 (2)
Ca^iii—O1—O1^ix	111.27 (10)	Cas^xv—O2—Cas^xvii	113 (2)
Ca^iii—O1—O1^x	111.27 (11)	Cas^xvi—O2—Cas^xv	113 (2)
Ca^iii—O1—O1^xi	98.05 (11)	Cas^xvi—O2—Cas^xvii	113 (2)
Ca^iii—O1—O1^xii	52.74 (8)	Cas^xvii—O2—Cas^xv	113 (2)
Ca^iii—O1—O2^xiii	111.70 (9)	Cas^xvii—O2—Cas^xvi	113 (2)
Ca^iii—O1—Cas^xiv	86.8 (9)	Ca—O3—Ca^iii	180
Al1^xiii—O1—Al2	138.96 (15)	Ca—O3—Cas	0
Al1^xiii—O1—O1^viii	131.11 (14)	Ca—O3—Cas^iii	180
Al1^xiii—O1—O1^ix	106.39 (13)	Ca^iii—O3—Ca	180
Al1^xiii—O1—O1^x	155.43 (15)	Ca^iii—O3—Cas	180
Al1^xiii—O1—O1^xi	38.92 (11)	Ca^iii—O3—Cas^iii	0
Al1^xiii—O1—O1^xii	38.92 (11)	Cas—O3—Cas^iii	180
Al1^xiii—O1—O2^xiii	31.40 (11)	Cas^iii—O3—Cas	180
Al1^xiii—O1—Cas^xiv	115.9 (17)	Ca—Cas—O1^i	72.3 (19)
Al2—O1—O1^viii	37.15 (6)	Ca—Cas—O1^ii	72.3 (19)
Al2—O1—O1^ix	34.31 (6)	Ca—Cas—O2^v	82 (2)
Al2—O1—O1^x	34.31 (6)	Ca—Cas—O2^vi	82 (2)
Al2—O1—O1^xi	166.76 (12)	Ca—Cas—O3	180
Al2—O1—O1^xii	128.49 (10)	O1^i—Cas—O1^ii	145 (4)
Al2—O1—O2^xiii	110.77 (10)	O1^i—Cas—O2^v	95.2 (10)
Al2—O1—Cas^xiv	104.9 (16)	O1^i—Cas—O2^vi	80.1 (8)
O1^viii—O1—O1^ix	61.15 (7)	O1^i—Cas—O3	107.7 (19)
O1^viii—O1—O1^x	61.15 (7)	O1^ii—Cas—O1^i	145 (4)
O1^viii—O1—O1^xi	155.87 (11)	O1^ii—Cas—O2^v	80.1 (8)
O1^viii—O1—O1^xii	99.33 (9)	O1^ii—Cas—O2^vi	95.2 (10)
O1^viii—O1—O2^xiii	121.72 (9)	O1^ii—Cas—O3	107.7 (19)
O1^viii—O1—Cas^xiv	100.6 (19)	O2^v—Cas—O2^vi	165 (4)
O1^ix—O1—O1^viii	61.15 (7)	O2^v—Cas—O3	98 (2)
O1^ix—O1—O1^x	57.69 (7)	O2^vi—Cas—O2^v	165 (4)
O1^ix—O1—O1^xi	136.16 (9)	O2^vi—Cas—O3	98 (2)
O1^ix—O1—O1^xii	114.07 (9)

Symmetry codes: (i) −y+1/4, −x+3/4, z−1/4; (ii) −y+1/4, x−3/4, −z+3/4; (iii) −x+3/4, z−1/4, −y+1/4; (iv) −x+3/4, −z+1/4, y+1/4; (v) y+1/4, −x−1/4, −z+1/4; (vi) y+1/4, x+1/4, z+1/4; (vii) z−1/4, −y+1/4, −x+3/4; (viii) x, −y, −z+1/2; (ix) −x+7/4, z−1/4, −y+1/4; (x) −x+7/4, −z+1/4, y+1/4; (xi) −z+1, x−1/2, −y+1/2; (xii) y+1/2, −z+1/2, −x+1; (xiii) −y+3/4, −x+1/4, z+1/4; (xiv) y+3/4, −x+1/4, −z+3/4; (xv) x−1/4, −z+1/4, −y−1/4; (xvi) −y−1/4, x−1/4, −z+1/4; (xvii) −z+1/4, −y−1/4, x−1/4.