Refinement of framework disorder in dehydrated CaA zeolite from single-crystal synchrotron data

Porcher, F.; Souhassou, M.; Graafsma, H.; Puig-Molina, A.; Dusausoy, Y.; Lecomte, C.

doi:10.1107/S0108768100006893

Refinement of framework disorder in dehydrated CaA zeolite from single-crystal synchrotron data

F. Porcher, M. Souhassou, H. Graafsma, A. Puig-Molina, Y. Dusausoy and C. Lecomte

An accurate knowledge of zeolite structure is required for understanding their selective sorption capacities and their catalytic properties. In particular, the positions of the exchangeable cations and their interactions with the framework are essential. The present study deals with the accurate crystal structure determination of a fully exchanged and fully dehydrated CaA zeolite (Ca₄₈Al₉₆Si₉₆O₃₈₄, Fm $\bar 3$ c, a = 24.47 Å) using single-crystal high-resolution synchrotron X-ray diffraction [(sin θ/λ)_max = 1.4 Å⁻¹]. It is shown that cation exchange severely distorts the skeleton, especially around the O2 atom. The high-resolution synchrotron data reveal that this latter O atom is disordered and lies out of the mirror plane it occupies in other A-type zeolites. This feature is related to that observed for Ca²⁺ cations.

Keywords: Dehydrated CaA zeolite; Disorder; Cation distribution.

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Supporting information

	Crystallographic Information File (CIF) https://doi.org/10.1107/S0108768100006893/br0095sup1.cif Contains datablocks hyp-a, hyp-b, hyp-c, hyp-d, global
	Structure factor file (CIF format) https://doi.org/10.1107/S0108768100006893/br0095hyp-bsup2.hkl Contains datablock II
	Structure factor file (CIF format) https://doi.org/10.1107/S0108768100006893/br0095hyp-csup3.hkl Contains datablock III
	Structure factor file (CIF format) https://doi.org/10.1107/S0108768100006893/br0095hyp-dsup4.hkl Contains datablock IV
	Portable Document Format (PDF) file https://doi.org/10.1107/S0108768100006893/br0095sup5.pdf Supplementary material

Computing details top

For all compounds, data collection: Siemens Smart; cell refinement: Siemens Smart; data reduction: Siemens Smart + SORTAV; program(s) used to solve structure: NRCVAX (Gabe et al., 1989); program(s) used to refine structure: MOLLY.

Figures top

(hyp-a) top

Crystal data top

Al₉₆Ca₄₈O₃₈₄Si₉₆	Z = 1
M_r = 13380.3	D_x = 1.517 Mg m⁻³
Cubic, Fm3c	Synchrotron radiation, λ = 0.248 Å
Hall symbol: -F 4n 2 3	T = 293 K
a = 24.47 Å	Transparent cubic crystals, colourless
V = 14652 Å³	0.11 × 0.10 × 0.09 mm

Data collection top

Siemens Smart CCD diffractometer	R_int = 0.059
Radiation source: E.S.R.F.	θ_max = 20.3°
ω scans	h = −34→64
16629 measured reflections	k = −61→34
1269 independent reflections	l = −54→57
1269 reflections with I > 0

Refinement top

Refinement on F	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.077	w = 1/σ²
wR(F²) = 0.074	(Δ/σ)_max = 0.3
S = 2.96	Δρ_max = 6.4 e Å⁻³
1147 reflections	Δρ_min = 1.5 e Å⁻³
48 parameters

Crystal data top

Al₉₆Ca₄₈O₃₈₄Si₉₆	Z = 1
M_r = 13380.3	Synchrotron radiation, λ = 0.248 Å
Cubic, Fm3c	T = 293 K
a = 24.47 Å	0.11 × 0.10 × 0.09 mm
V = 14652 Å³

Data collection top

Siemens Smart CCD diffractometer	1269 reflections with I > 0
16629 measured reflections	R_int = 0.059
1269 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.077	48 parameters
wR(F²) = 0.074	(Δ/σ)_max = 0.3
S = 2.96	Δρ_max = 6.4 e Å⁻³
1147 reflections	Δρ_min = 1.5 e Å⁻³

Special details top

Geometry. All e.s.d.'s are estimated using the full covariance matrix.

Refinement. Refinement on F for all reflections with F > 0*σ(F_o). Using synchrotron radiation allows a large number (245) of substructure reflections to be observed and used for solving and refining the structure.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq	Occ. (<1)
Si	0 (0)	0.09214 (6)	0.18414 (5)	0.0161 (6)
Al	0 (0)	0.18742 (5)	0.09096 (7)	0.0176 (6)
O1	0 (0)	0.1088 (2)	0.2460 (2)	0.046 (2)
O2	0 (0)	0.14216 (2)	0.1435 (2)	0.067 (3)
O3	0.0535 (1)	0.05741 (1)	0.1678 (1)	0.045 (2)
Ca1	0.0683 (3)	0.0683 (3)	0.0683 (3)	0.042 (2)	0.15
Ca2	0.08698 (2)	0.08698 (2)	0.08698 (2)	0.046 (1)	0.3
Ca3	0.105 (2)	0.0977 (3)	0.109 (2)	0.03 (1)	0.1

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Si	0.0217 (6)	0.0151 (6)	0.0115 (5)	0 (0)	0 (0)	0.0051 (4)
Al	0.0271 (8)	0.0108 (6)	0.0149 (6)	0 (0)	0 (0)	0.0043 (5)
O1	0.071 (3)	0.054 (2)	0.012 (1)	0 (0)	0 (0)	−0.001 (2)
O2	0.130 (4)	0.036 (3)	0.036 (3)	0 (0)	0 (0)	0.029 (2)
O3	0.039 (2)	0.046 (2)	0.051 (1)	0.019 (1)	0.000 (1)	0.005 (1)
Ca1	0.042 (2)	0.042 (2)	0.042 (2)	0.010 (3)	0.010 (3)	0.010 (3)
Ca2	0.046 (1)	0.046 (1)	0.046 (1)	0.012 (2)	0.012 (2)	0.012 (2)
Ca3	0.03 (1)	0.03 (1)	0.03 (1)	0.019 (6)	−0.002 (6)	0.006 (4)

Geometric parameters (Å, º) top

Si—O1	1.568 (5)	Ca2—O3	2.260 (2)
Si—O2	1.577 (3)	Ca2—O2	2.875 (2)
Si—O3	1.611 (2)	Ca3—O3	2.15 (4)
Al—O1	1.687 (5)	Ca3—O3	2.26 (4)
Al—O2	1.697 (4)	Ca3—O3	2.48 (4)
Al—O3	1.745 (2)	Ca3—O2	2.69 (2)
Ca1—O3	2.476 (8)	Ca3—O2	2.92 (5)

Si—O1—Al	149.9 (3)	O3—Si—O3	108.7 (1)
Si—O2—Al	169.8 (3)	O1—Al—O2	115.7 (2)
Si—O3—Al	141.6 (2)	O1—Al—O3	113.7 (1)
O1—Si—O2	114.0 (2)	O2—Al—O3	102.6 (1)
O1—Si—O3	112.1 (1)	O3—Al—O3	107.3 (1)
O2—Si—O3	104.7 (1)

(hyp-b) top

Crystal data top

Al₉₆Ca₄₈O₃₈₄Si₉₆	Z = 1
M_r = 13380.3	D_x = 1.517 Mg m⁻³
Cubic, Fm3c	Synchrotron radiation, λ = 0.248 Å
Hall symbol: -F 4n 2 3	T = 293 K
a = 24.47 Å	Transparent cubic crystals, colourless
V = 14652 Å³	0.11 × 0.10 × 0.09 mm

Data collection top

Siemens Smart CCD diffractometer	R_int = 0.059
Radiation source: E.S.R.F.	θ_max = 20.3°
ω scans	h = −34→64
16629 measured reflections	k = −61→34
1269 independent reflections	l = −54→57
1269 reflections with I > 0

Refinement top

Refinement on F	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.070	w = 1/σ²
wR(F²) = 0.067	(Δ/σ)_max = 0.02
S = 2.56	Δρ_max = 6.1 e Å⁻³
1147 reflections	Δρ_min = 1.1 e Å⁻³
52 parameters

Crystal data top

Al₉₆Ca₄₈O₃₈₄Si₉₆	Z = 1
M_r = 13380.3	Synchrotron radiation, λ = 0.248 Å
Cubic, Fm3c	T = 293 K
a = 24.47 Å	0.11 × 0.10 × 0.09 mm
V = 14652 Å³

Data collection top

Siemens Smart CCD diffractometer	1269 reflections with I > 0
16629 measured reflections	R_int = 0.059
1269 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.070	52 parameters
wR(F²) = 0.067	Δρ_max = 6.1 e Å⁻³
S = 2.56	Δρ_min = 1.1 e Å⁻³
1147 reflections

Special details top

Geometry. All e.s.d.'s are estimated using the full covariance matrix.

Refinement. Refinement on F for all reflections with F > 0*σ(F_o). Using synchrotron radiation allows a large number (183) of substructure reflections to be observed and used for solving and refining the structure.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq	Occ. (<1)
Si	0.00000 (1)	0.09216 (6)	0.18413 (5)	0.01648 (5)
Al	0.00000 (1)	0.18738 (5)	0.09095 (6)	0.0180 (6)
O1	0.00000 (1)	0.1088 (1)	0.2460 (2)	0.047 (2)
O2	0.0115 (1)	0.1423 (2)	0.1436 (2)	0.031 (3)	0.5
O3	0.0539 (1)	0.0577 (1)	0.1676 (1)	0.045 (2)
Ca1	0.0685 (1)	0.0685 (1)	0.0685 (1)	0.040 (2)	0.15
Ca2	0.0874 (2)	0.0874 (2)	0.0874 (2)	0.0446 (1)	0.3
Ca3	0.1052 (9)	0.0977 (2)	0.1090 (9)	0.023 (4)	0.1

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Si	0.02197 (6)	0.01516 (5)	0.01230 (5)	0.00000 (1)	0.00000 (1)	0.0051 (4)
Al	0.0277 (7)	0.0112 (5)	0.0151 (6)	0.00000 (1)	0.00000 (1)	0.00455 (5)
O1	0.076 (2)	0.053 (2)	0.013 (1)	0.00000 (1)	0.00000 (1)	−0.002 (2)
O2	0.033 (2)	0.024 (3)	0.036 (3)	0.008 (2)	0.007 (2)	0.027 (1)
O3	0.039 (2)	0.046 (2)	0.051 (1)	0.020 (1)	−0.001 (1)	−0.006 (1)
Ca1	0.040 (2)	0.040 (2)	0.040 (2)	0.010 (2)	0.010 (2)	0.010 (2)
Ca2	0.0446 (1)	0.0446 (1)	0.0446 (1)	0.013 (1)	0.013 (1)	0.013 (1)
Ca3	0.040 (7)	0.011 (2)	0.017 (3)	0.020 (4)	−0.003 (3)	0.004 (3)

Geometric parameters (Å, º) top

Si—O1	1.568 (5)	Ca1—O3	2.465 (3)
Si—O2	1.603 (5)	Ca2—O3	2.248 (5)
Si—O3	1.617 (3)	Ca3—O3	2.14 (2)
Al—O1	1.688 (5)	Ca3—O3	2.25 (2)
Al—O2	1.719 (5)	Ca3—O3	2.47 (2)
Al—O3	1.746 (3)

Si—O1—Al	150.0 (2)	O3—Si—O3	109.3 (2)
Si—O2—Al	157.9 (2)	O1—Al—O2	115.2 (2)
Si—O3—Al	140.9 (2)	O1—Al—O3	113.7 (1)
O1—Si—O2	113.5 (2)	O2—Al—O3	110.1 (2)
O1—Si—O3	112.2 (1)	O2—Al—O3	94.5 (2)
O2—Si—O3	95.8 (2)	O3—Al—O3	107.9 (1)
O2—Si—O3	112.8 (2)

(hyp-c) top

Crystal data top

Al₉₆Ca₄₈O₃₈₄Si₉₆	Z = 1
M_r = 13380.3	D_x = 1.517 Mg m⁻³
Cubic, Fm3c	Synchrotron radiation, λ = 0.248 Å
Hall symbol: -F 4n 2 3	T = 293 K
a = 24.47 Å	Transparent cubic crystals, colourless
V = 14652 Å³	0.11 × 0.10 × 0.09 mm

Data collection top

Siemens Smart CCD diffractometer	R_int = 5.93
Radiation source: E.S.R.F.	θ_max = 20.3°
ω scans	h = −34→64
16629 measured reflections	k = −61→34
1269 independent reflections	l = −54→57
1269 reflections with I > 0

Refinement top

Refinement on F	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.066	w = 1/σ²
wR(F²) = 0.062	(Δ/σ)_max = 0.02
S = 2.38	Δρ_max = 1.4 e Å⁻³
1147 reflections	Δρ_min = 1.4 e Å⁻³
57 parameters

Crystal data top

Al₉₆Ca₄₈O₃₈₄Si₉₆	Z = 1
M_r = 13380.3	Synchrotron radiation, λ = 0.248 Å
Cubic, Fm3c	T = 293 K
a = 24.47 Å	0.11 × 0.10 × 0.09 mm
V = 14652 Å³

Data collection top

Siemens Smart CCD diffractometer	1269 reflections with I > 0
16629 measured reflections	R_int = 5.93
1269 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.066	57 parameters
wR(F²) = 0.062	Δρ_max = 1.4 e Å⁻³
S = 2.38	Δρ_min = 1.4 e Å⁻³
1147 reflections

Special details top

Geometry. All e.s.d.'s are estimated using the full covariance matrix.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq	Occ. (<1)
Si	0	0.09216 (5)	0.18412 (4)	0.01648 (5)
Al	0	0.18738 (4)	0.09095 (6)	0.0180 (6)
O1	0	0.1087 (1)	0.2460 (1)	0.047 (2)
O2	0.0115 (1)	0.1423 (2)	0.1436 (2)	0.031 (3)	0.5
O3	0.0539 (1)	0.0576 (1)	0.16765 (9)	0.045 (2)
Ca1	0.0718 (9)	0.0718 (9)	0.0718 (9)	0.040 (2)	0.25 (2)
Ca2	0.0874 (3)	0.0874 (3)	0.0874 (3)	0.0446 (1)	0.17 (2)
Ca3	0.1050 (7)	0.0972 (3)	0.1069 (8)	0.023 (4)	0.124 (3)
Ca4	0 (0)	0 (0)	0 (0)	0.02 (1)*	0.08 (1)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Si	0.0218 (5)	0.0150 (5)	0.0123 (5)	0	0	0.0051 (4)
Al	0.0275 (6)	0.0111 (5)	0.0151 (5)	0	0	0.0046 (4)
O1	0.074 (2)	0.053 (2)	0.013 (1)	0	0	−0.002 (2)
O2	0.033 (2)	0.034 (2)	0.035 (2)	0.008 (2)	0.007 (2)	0.026 (2)
O3	0.040 (2)	0.046 (2)	0.050 (1)	0.0194 (9)	−0.001 (1)	−0.006 (1)
Ca1	0.072 (7)	0.072 (7)	0.072 (7)	0.037 (7)	0.037 (7)	0.037 (7)
Ca2	0.027 (3)	0.027 (3)	0.027 (3)	−0.003 (2)	−0.003 (2)	−0.003 (2)
Ca3	0.055 (7)	0.020 (3)	0.026 (4)	0.027 (4)	−0.000 (3)	0.006 (3)

Geometric parameters (Å, º) top

Si—O1	1.568 (5)	Ca1—O3	2.465 (3)
Si—O2	1.603 (5)	Ca2—O3	2.248 (5)
Si—O3	1.617 (3)	Ca3—O3	2.14 (2)
Al—O1	1.688 (5)	Ca3—O3	2.25 (2)
Al—O2	1.719 (5)	Ca3—O3	2.47 (2)
Al—O3	1.746 (3)

Si—O1—Al	150.0 (2)	O3—Si—O3	109.3 (2)
Si—O2—Al	157.9 (2)	O1—Al—O2	115.2 (2)
Si—O3—Al	140.9 (2)	O1—Al—O3	113.7 (1)
O1—Si—O2	113.5 (2)	O2—Al—O3	110.1 (2)
O1—Si—O3	112.2 (1)	O2—Al—O3	94.5 (2)
O2—Si—O3	95.8 (2)	O3—Al—O3	107.9 (1)
O2—Si—O3	112.8 (2)

(hyp-d) top

Crystal data top

Al₉₆Ca₄₈O₃₈₄Si₉₆	Z = 1
M_r = 13380.3	D_x = 1.517 Mg m⁻³
Cubic, F43c	Synchrotron radiation, λ = 0.248 Å
Hall symbol: F -4c 2 3	T = 293 K
a = 24.47 Å	Transparent cubic crystals, colourless
V = 14652 Å³	0.11 × 0.10 × 0.09 mm

Data collection top

Siemens Smart CCD diffractometer	R_int = 5.93
Radiation source: E.S.R.F.	θ_max = 20.3°
ω scans	h = −34→64
16629 measured reflections	k = −61→34
1269 independent reflections	l = −54→57
1269 reflections with I > 0

Refinement top

Refinement on F	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.070	w = 1/σ²
wR(F²) = 0.067	(Δ/σ)_max = 0.2
S = 2.45	Δρ_max = 6.5 e Å⁻³
1147 reflections	Δρ_min = 1.2 e Å⁻³
78 parameters

Crystal data top

Al₉₆Ca₄₈O₃₈₄Si₉₆	Z = 1
M_r = 13380.3	Synchrotron radiation, λ = 0.248 Å
Cubic, F43c	T = 293 K
a = 24.47 Å	0.11 × 0.10 × 0.09 mm
V = 14652 Å³

Data collection top

Siemens Smart CCD diffractometer	1269 reflections with I > 0
16629 measured reflections	R_int = 5.93
1269 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.070	78 parameters
wR(F²) = 0.067	(Δ/σ)_max = 0.2
S = 2.45	Δρ_max = 6.5 e Å⁻³
1147 reflections	Δρ_min = 1.2 e Å⁻³

Special details top

Geometry. All e.s.d.'s are estimated using the full covariance matrix.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq	Occ. (<1)
Si	0.0006 (2)	0.09217 (6)	0.18416 (5)	0.0168 (6)
Al	−0.0007 (2)	0.18732 (5)	0.09098 (7)	0.0180 (6)
O1	0.0011 (7)	0.1085 (2)	0.2462 (2)	0.049 (2)
O2a	0.0120 (6)	0.1394 (5)	0.1409 (6)	0.030 (6)	0.5
O2b	−0.0102 (6)	0.1468 (7)	0.1478 (7)	0.036 (8)	0.5
O3a	0.0557 (4)	0.0574 (4)	0.1647 (3)	0.040 (5)
O3b	−0.0524 (4)	0.0579 (4)	0.1709 (3)	0.045 (5)
Ca1	−0.0689 (3)	0.0689 (3)	0.0689 (3)	0.048 (2)	0.25 (2)
Ca2	0.0858 (3)	0.0858 (3)	0.0858 (3)	0.045 (2)	0.17 (2)
Ca3a	−0.0975 (4)	0.0975 (4)	0.0975 (4)	0.062 (4)	0.124 (3)
Ca3b	0.1011 (7)	0.0997 (7)	0.1127 (3)	0.017 (1)*	0.08 (1)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Si	0.0222 (6)	0.0159 (6)	0.0124 (5)	−0.008 (1)	0.003 (1)	0.0054 (4)
Al	0.0279 (7)	0.0114 (6)	0.0147 (6)	−0.000 (2)	−0.000 (2)	0.0040 (5)
O1	0.078 (3)	0.055 (2)	0.014 (1)	−0.014 (7)	0.013 (5)	−0.002 (2)
O2a	0.044 (6)	0.015 (4)	0.031 (6)	0.016 (4)	0.022 (5)	0.016 (2)
O2b	0.028 (7)	0.05 (1)	0.031 (7)	−0.001 (7)	0.006 (6)	0.025 (4)
O3a	0.042 (5)	0.039 (6)	0.039 (3)	0.014 (3)	0.004 (3)	−0.003 (3)
O3b	0.034 (4)	0.053 (6)	0.049 (4)	−0.028 (3)	0.000 (3)	−0.010 (3)
Ca1	0.048 (2)	0.048 (2)	0.048 (2)	−0.022 (3)	−0.022 (3)	−0.022 (3)
Ca2	0.045 (2)	0.045 (2)	0.045 (2)	0.008 (2)	0.008 (2)	0.008 (2)
Ca3a	0.062 (4)	0.062 (4)	0.062 (4)	0.036 (5)	0.036 (5)	0.036 (5)

Experimental details

	(hyp-a)	(hyp-b)	(hyp-c)	(hyp-d)
Crystal data
Chemical formula	Al₉₆Ca₄₈O₃₈₄Si₉₆	Al₉₆Ca₄₈O₃₈₄Si₉₆	Al₉₆Ca₄₈O₃₈₄Si₉₆	Al₉₆Ca₄₈O₃₈₄Si₉₆
M_r	13380.3	13380.3	13380.3	13380.3
Crystal system, space group	Cubic, Fm3c	Cubic, Fm3c	Cubic, Fm3c	Cubic, F43c
Temperature (K)	293	293	293	293
a (Å)	24.47	24.47	24.47	24.47
V (Å³)	14652	14652	14652	14652
Z	1	1	1	1
Radiation type	Synchrotron, λ = 0.248 Å	Synchrotron, λ = 0.248 Å	Synchrotron, λ = 0.248 Å	Synchrotron, λ = 0.248 Å
µ (mm⁻¹)	?	?	?	?
Crystal size (mm)	0.11 × 0.10 × 0.09	0.11 × 0.10 × 0.09	0.11 × 0.10 × 0.09	0.11 × 0.10 × 0.09

Data collection
Diffractometer	Siemens Smart CCD diffractometer	Siemens Smart CCD diffractometer	Siemens Smart CCD diffractometer	Siemens Smart CCD diffractometer
Absorption correction	?	?	?	?
No. of measured, independent and observed (I > 0) reflections	16629, 1269, 1269	16629, 1269, 1269	16629, 1269, 1269	16629, 1269, 1269
R_int	0.059	0.059	5.93	5.93
(sin θ/λ)_max (Å⁻¹)	1.400	1.400	1.400	1.400

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.077, 0.074, 2.96	0.070, 0.067, 2.56	0.066, 0.062, 2.38	0.070, 0.067, 2.45
No. of reflections	1147	1147	1147	1147
No. of parameters	48	52	57	78
No. of restraints	?	?	?	?
(Δ/σ)_max	0.3	0.02	0.02	0.2
Δρ_max, Δρ_min (e Å⁻³)	6.4, 1.5	6.1, 1.1	1.4, 1.4	6.5, 1.2

Computer programs: , Siemens Smart + SORTAV, NRCVAX (Gabe et al., 1989), MOLLY.

Selected geometric parameters (Å, º) for (hyp-a) top

Si—O1	1.568 (5)	Ca2—O3	2.260 (2)
Si—O2	1.577 (3)	Ca2—O2	2.875 (2)
Si—O3	1.611 (2)	Ca3—O3	2.15 (4)
Al—O1	1.687 (5)	Ca3—O3	2.26 (4)
Al—O2	1.697 (4)	Ca3—O3	2.48 (4)
Al—O3	1.745 (2)	Ca3—O2	2.69 (2)
Ca1—O3	2.476 (8)	Ca3—O2	2.92 (5)

Si—O1—Al	149.9 (3)	O3—Si—O3	108.7 (1)
Si—O2—Al	169.8 (3)	O1—Al—O2	115.7 (2)
Si—O3—Al	141.6 (2)	O1—Al—O3	113.7 (1)
O1—Si—O2	114.0 (2)	O2—Al—O3	102.6 (1)
O1—Si—O3	112.1 (1)	O3—Al—O3	107.3 (1)
O2—Si—O3	104.7 (1)

Selected geometric parameters (Å, º) for (hyp-b) top

Si—O1	1.568 (5)	Ca1—O3	2.465 (3)
Si—O2	1.603 (5)	Ca2—O3	2.248 (5)
Si—O3	1.617 (3)	Ca3—O3	2.14 (2)
Al—O1	1.688 (5)	Ca3—O3	2.25 (2)
Al—O2	1.719 (5)	Ca3—O3	2.47 (2)
Al—O3	1.746 (3)

Si—O1—Al	150.0 (2)	O3—Si—O3	109.3 (2)
Si—O2—Al	157.9 (2)	O1—Al—O2	115.2 (2)
Si—O3—Al	140.9 (2)	O1—Al—O3	113.7 (1)
O1—Si—O2	113.5 (2)	O2—Al—O3	110.1 (2)
O1—Si—O3	112.2 (1)	O2—Al—O3	94.5 (2)
O2—Si—O3	95.8 (2)	O3—Al—O3	107.9 (1)
O2—Si—O3	112.8 (2)

Selected geometric parameters (Å, º) for (hyp-c) top

Si—O1	1.568 (5)	Ca1—O3	2.465 (3)
Si—O2	1.603 (5)	Ca2—O3	2.248 (5)
Si—O3	1.617 (3)	Ca3—O3	2.14 (2)
Al—O1	1.688 (5)	Ca3—O3	2.25 (2)
Al—O2	1.719 (5)	Ca3—O3	2.47 (2)
Al—O3	1.746 (3)

Si—O1—Al	150.0 (2)	O3—Si—O3	109.3 (2)
Si—O2—Al	157.9 (2)	O1—Al—O2	115.2 (2)
Si—O3—Al	140.9 (2)	O1—Al—O3	113.7 (1)
O1—Si—O2	113.5 (2)	O2—Al—O3	110.1 (2)
O1—Si—O3	112.2 (1)	O2—Al—O3	94.5 (2)
O2—Si—O3	95.8 (2)	O3—Al—O3	107.9 (1)
O2—Si—O3	112.8 (2)

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