inorganic papers
i102
Matthias Weil Cd3[Si3O9] doi:10.1107/S1600536805015278 Acta Cryst.(2005). E61, i102–i104
Acta Crystallographica Section E
Structure Reports Online
ISSN 1600-5368
Parawollastonite-type Cd
3[Si
3O
9]
Matthias Weil
Institute for Chemical Technologies and Analytics, Division of Structural Chemistry, Vienna University of Technology, Getreidemarkt 9/164-SC, A-1060 Vienna, Austria
Correspondence e-mail: mweil@mail.zserv.tuwien.ac.at
Key indicators
Single-crystal X-ray study
T= 293 K
Mean(Si–O) = 0.002 A˚
Rfactor = 0.023
wRfactor = 0.064
Data-to-parameter ratio = 17.6
For details of how these key indicators were automatically derived from the article, see http://journals.iucr.org/e.
#2005 International Union of Crystallography
Printed in Great Britain – all rights reserved
Cd3[Si3O9] (tricadmium trisilicate) crystallizes in the
mono-clinic space group P21/c and is isotypic with the mineral
parawollastonite, Ca3[Si3O9]-2M. The structure contains
distorted CdO6 octahedra and SiO4 tetrahedra that are
organized in unbranched dreier single chains with three SiO4tetrahedra in the repeat unit. All atoms occupy general
positions 4e.
Comment
Cadmium silicates are of particular interest because of their properties as host materials for luminescent applications when doped with rare earth or transition metal ions. Recently, some CdSiO3:REphosphors (RE = rare earth) with a long-lasting
phosphorescence upon UV-light excitation were reported (Liu
et al., 2005).
[image:1.610.227.437.359.721.2]Received 5 May 2005 Accepted 13 May 2005 Online 21 May 2005
Figure 1
In the system CdO—SiO2, three compounds are known to
exist: the orthosilicate Cd2SiO4 which crystallizes in the
thenardite structure type (Dent Glasser & Glasser, 1964), the oxyorthosilicate Cd3OSiO4 with a unique structure (Eysel,
1970), and the polysilicate CdSiO3for which only powder data
were published (Dent Glasser & Glasser, 1964). In the original work, it was not possible to determine the space group of CdSiO3 unequivocally because the crystals were
poly-synthetically twinned. However, powder data revealed a structural relation to the calcium analogue, CaSiO3. The latter
occurs in different polymorphs with structurally quite different arrangements. The high-temperature phase is a cyclosilicate called -wollastonite or pseudowollastonite. Its structure contains rings of three corner-shared SiO4
tetra-hedra organized in a layered arrangement. Depending on the stacking sequence of the layers, a number of polytypes were reported for pseudowollastonite (Yamanaka & Mori, 1981). The low-temperature phases of calcium polysilicate are made up of unbranched single chains of corner-shared SiO4
tetra-hedra. Two polytypes have been reported for the low-temperature phase, often referred to as-wollastonites. They are distinguished by the symbolsnTandnM, whereTandM
symbolize the triclinic and monoclinic symmetry, andn indi-cates the number of subcells. The polytype 1Tis also named wollastonite whereas the polytype 2M is a synonym for parawollastonite (Trojer, 1968; Hesse, 1984). For all poly-morphs, the chemical formulae CaSiO3, Ca3(SiO3)3 or
Ca3[Si3O9] are reported in the literature.
Although it was reported that cadmium polysilicate can occur in different polytypes (Dent Glasser & Glasser, 1964), only the form that is isotypic with parawollastonite was obtained during the present investigation. In accordance with the nomenclature of condensed silicates given by Liebau (1985), the formula of the title compound is written as Cd3[Si3O9].
The Cd3[Si3O9] structure differs only slightly from that of
the isotypic Ca phase (Hesse, 1984), mainly in changes in the Cd—O distances versus the Ca—O distances resulting from the different ionic radii (Shannon, 1976) of 0.95 (Cd2+; CN = 6) and 1.00 A˚ (Ca2+; CN = 6), respectively.
The three independent Cd atoms are each surrounded by six O atoms, forming distorted CdO6 octahedra which are
arranged in slabs parallel to [010]. Three such slabs constitute
ribbons which are separated from each other by unbranched silicate chains that are formed by corner-sharing SiO4
tetra-hedra (Fig. 1). The silicate chains have a repeating period of three SiO4 tetrahedra (Fig. 2) which corresponds with the
length of the baxis. According to Liebau’s (1985) notation, Cd3[Si3O9] is a dreier single chain polysilicate.
The mean Cd—O distances of 2.326 (Cd1), 2.333 (Cd2) and 2.341 A˚ (Cd3) are slightly shorter than the corresponding mean Ca—O distances of 2.385 (Ca1), 2.378 (Ca2) and 2.385 A˚ (Ca3), whereas the mean Si—O distances in Cd3[Si3O9] and
Ca3[Si3O9] are virtually the same,viz. 1.620, 1.627 and 1.635 A˚
in the Cd compoundversus1.620, 1.617 and 1.630 A˚ in the Ca compound. The O—Si—O angles of the silicate chains are very similar in both isotypic structures and are in the range 102.06 (9)–122.12 (10)in the Cd compoundversus102.5 (1)– 122.0 (1)in the Ca compound.
Experimental
CdCO3(Merck, p. A.) and high-surface silica (Degussa–Hu¨ls) were
mixed in the stoichiometric ratio 2:1 and slowly heated in a platinum crucible to 1023 K for 24 h. X-ray powder diffraction of the
poly-crystalline material revealed a mixture of Cd2SiO4(Dent Glasser &
Glasser, 1964) and Cd3[Si3O9]. The mixture was then heated to
1473 K, left at that temperature for 2 h and cooled slowly to 1173 K at
a rate of 4 K h1. The furnace was then shut down. After cooling to
room temperature, the colourless melt was crushed and a plate-like single-crystal was used for the data collection. X-ray powder
diffraction of the final product yielded Cd3[Si3O9], isotypic with
Ca3[Si3O9]-2M, and only minor amounts of Cd2SiO4.
Crystal data
Cd3[Si3O9]
Mr= 565.47 Monoclinic,P21=c
a= 6.9463 (8) A˚
b= 7.2563 (9) A˚
c= 15.0697 (18) A˚
= 94.791 (2) V= 756.93 (16) A˚3
Z= 4
Dx= 4.962 Mg m3 MoKradiation Cell parameters from 4479
reflections
= 2.7–31.2 = 8.86 mm1
T= 293 (2) K Plate, colourless 0.260.140.02 mm
Data collection
Bruker SMART APEX CCD diffractometer
!scans
Absorption correction: multi-scan (SADABS; Bruker, 2002)
Tmin= 0.203,Tmax= 0.816
8622 measured reflections
2412 independent reflections 1980 reflections withI> 2(I)
Rint= 0.037
max= 31.2
h=8!9
k=10!10
l=21!19
Refinement
Refinement onF2
R[F2> 2(F2)] = 0.024
wR(F2) = 0.064
S= 1.07 2412 reflections 137 parameters
w= 1/[2(Fo2) + (0.0215P)2
+ 1.0847P]
whereP= (Fo2+ 2Fc2)/3
(/)max= 0.001
max= 1.60 e A˚
3
min=1.38 e A˚
3
Extinction correction:SHELXL97
Extinction coefficient: 0.00358 (19)
inorganic papers
Acta Cryst.(2005). E61, i102–i104 Matthias Weil Cd
[image:2.610.44.298.71.162.2]3[Si3O9]
i103
Figure 2Table 1
Selected geometric parameters (A˚ ,).
Cd1—O6 2.272 (2) Cd1—O1i 2.3045 (18) Cd1—O9ii 2.317 (2) Cd1—O2iii 2.3214 (19) Cd1—O1 2.3519 (19) Cd1—O2 2.3869 (19) Cd2—O4iv
2.1681 (17) Cd2—O3 2.2113 (17) Cd2—O1i 2.260 (2) Cd2—O7v
2.3939 (17) Cd2—O6 2.4538 (18) Cd2—O9v 2.5102 (18) Cd3—O4vi 2.2262 (17) Cd3—O2iii 2.249 (2) Cd3—O3 2.3073 (17)
Cd3—O8 2.3743 (16) Cd3—O6 2.4293 (18) Cd3—O9vii
2.4573 (18) Si1—O3viii
1.592 (2) Si1—O1 1.620 (2) Si1—O5 1.6219 (15) Si1—O7 1.6447 (17) Si2—O4 1.602 (2) Si2—O2 1.612 (2) Si2—O5 1.6158 (15) Si2—O8v
1.6399 (17) Si3—O6 1.599 (2) Si3—O9 1.605 (2) Si3—O7v
1.6529 (16) Si3—O8 1.6611 (16) O3viii
—Si1—O1 115.83 (11) O3viii
—Si1—O5 107.63 (9) O1—Si1—O5 108.44 (9) O3viii
—Si1—O7 114.32 (10) O1—Si1—O7 107.54 (10) O5—Si1—O7 102.06 (9) O4—Si2—O2 115.78 (11) O4—Si2—O5 106.92 (9) O2—Si2—O5 109.09 (9) O4—Si2—O8v 113.60 (10) O2—Si2—O8v
107.89 (10)
O5—Si2—O8v
102.69 (9) O6—Si3—O9 122.12 (10) O6—Si3—O7v 104.20 (9) O9—Si3—O7v
111.27 (9) O6—Si3—O8 103.48 (9) O9—Si3—O8 111.02 (9) O7v
—Si3—O8 102.80 (9) Si2—O5—Si1 148.03 (13) Si1—O7—Si3vii
139.89 (11) Si2vii—O8—Si3 140.61 (11)
Symmetry codes: (i) x;1
2þy;12z; (ii) x1;y;z; (iii) x;y12;12z; (iv)
x;3 2y;z
1
2; (v) 1x; 1 2þy;
1
2z; (vi) x; 1 2y;z
1
2; (vii) 1x;y 1 2;
1 2z; (viii)
x;1 2y;
1 2þz.
The structure was initially refined in space groupP21/awith the
atomic coordinates of the isotypic compound Ca3[Si3O9]-2M
(para-wollastonite; Hesse, 1984) as starting parameters. For the present
refinement, the standard setting inP21/cwas used and the structural
data were standardized using the program STRUCTURE-TIDY
(Gelato & Parthe´, 1987). The highest peak in the final Fourier map is
0.81 A˚ from atom Cd1 and the deepest hole is 1.64 A˚ from O8.
Data collection:SMART(Bruker, 2002); cell refinement:SAINT
(Bruker, 2002); data reduction:SAINT; method used to solve
struc-ture: coordinates taken from the isotypic Ca compound; program(s)
used to refine structure: SHELXL97 (Sheldrick, 1997); molecular
graphics:ATOMS(Dowty, 2004); software used to prepare material
for publication:SHELXL97.
References
Bruker (2002).SADABS,SMARTandSAINT.Bruker AXS Inc., Madison, Wisconsin, USA.
Dent Glasser, L. S. & Glasser, F. P. (1964).Inorg. Chem.3, 1228–1230. Dowty, E. (2004).ATOMS for Windows. Version 6.1. Shape Software, 521
Hidden Valley Road, Kingsport, TN 37663, USA. Eysel, W. (1970).Neues Jahrb. Mineral.Monatsh.pp. 534–547. Gelato, L. M. & Parthe´, E. (1987).J. Appl Cryst.20, 139–143. Hesse, K. F. (1984).Z. Kristallogr.168, 93–98.
Liebau, F. (1985).Structural Chemistry of Silicates: Structure, Bonding and Classification. Berlin: Springer-Verlag.
Liu, Y., Lei, B. & Shi, C. (2005).Chem. Mater.17, 2108–2113. Shannon, R. D. (1976).Acta Cryst.A32, 751–767.
Sheldrick, G. M. (1997).SHELXL97. University of Go¨ttingen, Germany. Trojer, F. (1968).Z. Kristallogr.127, 291–308.
Yamanaka, T. & Mori, H. (1981).Acta Cryst.B37, 1010–1027.
inorganic papers
i104
Matthias Weil Cdsupporting information
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Acta Cryst. (2005). E61, i102–i104
supporting information
Acta Cryst. (2005). E61, i102–i104 [https://doi.org/10.1107/S1600536805015278]
Parawollastonite-type Cd
3[Si
3O
9]
Matthias Weil
tricadmium trisilicate
Crystal data Cd3[Si3O9]
Mr = 565.47 Monoclinic, P21/c
Hall symbol: -P 2ybc a = 6.9463 (8) Å b = 7.2563 (9) Å c = 15.0697 (18) Å β = 94.791 (2)° V = 756.93 (16) Å3
Z = 4
F(000) = 1032 Dx = 4.962 Mg m−3
Mo Kα radiation, λ = 0.71073 Å Cell parameters from 4479 reflections θ = 2.7–31.2°
µ = 8.86 mm−1
T = 293 K Plate, colourless 0.26 × 0.14 × 0.02 mm
Data collection Bruker APEX CCD
diffractometer
Radiation source: fine-focus sealed tube Graphite monochromator
ω scans
Absorption correction: multi-scan (SADABS; Bruker, 2002) Tmin = 0.203, Tmax = 0.816
8622 measured reflections 2412 independent reflections 1980 reflections with I > 2σ(I) Rint = 0.037
θmax = 31.2°, θmin = 2.7°
h = −8→9 k = −10→10 l = −21→19
Refinement Refinement on F2
Least-squares matrix: full R[F2 > 2σ(F2)] = 0.024
wR(F2) = 0.064
S = 1.07 2412 reflections 137 parameters 0 restraints
Primary atom site location: isomorphous structure methods
w = 1/[σ2(F
o2) + (0.0215P)2 + 1.0847P]
where P = (Fo2 + 2Fc2)/3
(Δ/σ)max = 0.001
Δρmax = 1.60 e Å−3
Δρmin = −1.38 e Å−3
Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Extinction coefficient: 0.00358 (19)
Special details
supporting information
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Acta Cryst. (2005). E61, i102–i104
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 (Å2)
x y z Uiso*/Ueq
Cd1 0.01235 (2) 0.37607 (2) 0.248498 (10) 0.00866 (7) Cd2 0.24957 (3) 0.62788 (2) 0.098674 (12) 0.00993 (7) Cd3 0.25370 (2) 0.11992 (2) 0.101523 (12) 0.00989 (7) Si1 0.23852 (9) 0.16124 (8) 0.41008 (4) 0.00760 (12) Si2 0.23940 (9) 0.59016 (8) 0.41056 (4) 0.00734 (12) Si3 0.54611 (9) 0.37667 (7) 0.19864 (4) 0.00723 (12) O1 0.0431 (3) 0.1232 (2) 0.34626 (15) 0.0103 (4) O2 0.0428 (3) 0.6305 (2) 0.34907 (15) 0.0109 (4) O3 0.2259 (3) 0.3799 (2) 0.01320 (14) 0.0131 (4) O4 0.2314 (3) 0.6289 (2) 0.51484 (14) 0.0132 (4) O5 0.2977 (3) 0.37608 (19) 0.40041 (12) 0.0137 (3) O6 0.3173 (3) 0.3745 (2) 0.20452 (14) 0.0106 (4) O7 0.4167 (2) 0.0551 (2) 0.36594 (11) 0.0121 (3) O8 0.5842 (2) 0.1982 (2) 0.13334 (11) 0.0120 (3) O9 0.6954 (3) 0.3759 (2) 0.28588 (13) 0.0100 (4)
Atomic displacement parameters (Å2)
U11 U22 U33 U12 U13 U23
Cd1 0.00874 (11) 0.00846 (11) 0.00886 (12) −0.00002 (4) 0.00115 (8) 0.00004 (4) Cd2 0.01053 (11) 0.00889 (10) 0.01051 (11) 0.00156 (5) 0.00171 (7) 0.00156 (5) Cd3 0.00982 (11) 0.00962 (10) 0.01035 (11) −0.00154 (5) 0.00142 (7) −0.00174 (5) Si1 0.0080 (3) 0.0077 (2) 0.0070 (3) 0.00052 (19) −0.0003 (2) −0.0002 (2) Si2 0.0082 (3) 0.0073 (2) 0.0064 (3) −0.00049 (19) −0.0005 (2) −0.00004 (19) Si3 0.0064 (3) 0.0077 (2) 0.0075 (3) −0.00001 (18) 0.0000 (2) −0.00018 (19) O1 0.0089 (9) 0.0137 (9) 0.0084 (9) −0.0008 (6) 0.0005 (7) −0.0009 (6) O2 0.0090 (9) 0.0141 (9) 0.0093 (9) −0.0012 (6) 0.0000 (7) 0.0020 (6) O3 0.0202 (10) 0.0125 (8) 0.0067 (9) 0.0006 (6) 0.0010 (7) −0.0011 (6) O4 0.0235 (11) 0.0107 (8) 0.0053 (8) −0.0003 (6) 0.0012 (7) −0.0007 (6) O5 0.0182 (8) 0.0067 (7) 0.0165 (8) 0.0005 (5) 0.0044 (6) 0.0000 (5) O6 0.0058 (8) 0.0162 (8) 0.0099 (8) −0.0009 (6) 0.0004 (6) −0.0008 (6) O7 0.0110 (7) 0.0100 (6) 0.0150 (8) 0.0020 (5) −0.0008 (6) −0.0044 (6) O8 0.0105 (8) 0.0104 (7) 0.0149 (8) 0.0017 (5) 0.0001 (6) −0.0047 (6) O9 0.0077 (8) 0.0147 (8) 0.0074 (8) 0.0012 (6) −0.0018 (6) 0.0000 (6)
Geometric parameters (Å, º)
Cd1—O6 2.272 (2) Si1—O1 1.620 (2) Cd1—O1i 2.3045 (18) Si1—O5 1.6219 (15)
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Acta Cryst. (2005). E61, i102–i104
Cd1—O2iii 2.3214 (19) Si2—O4 1.602 (2)
Cd1—O1 2.3519 (19) Si2—O2 1.612 (2) Cd1—O2 2.3869 (19) Si2—O5 1.6158 (15) Cd1—O5 2.9000 (18) Si2—O8v 1.6399 (17)
Cd1—Cd2 3.4312 (3) Si3—O6 1.599 (2) Cd1—Cd3 3.4338 (3) Si3—O9 1.605 (2) Cd2—O4iv 2.1681 (17) Si3—O7v 1.6529 (16)
Cd2—O3 2.2113 (17) Si3—O8 1.6611 (16) Cd2—O1i 2.260 (2) O1—Cd2iii 2.260 (2)
Cd2—O7v 2.3939 (17) O1—Cd1iii 2.3045 (18)
Cd2—O6 2.4538 (18) O2—Cd3i 2.249 (2)
Cd2—O9v 2.5102 (18) O2—Cd1i 2.3214 (19)
Cd2—Si3 3.0524 (6) O3—Si1vi 1.592 (2)
Cd3—O4vi 2.2262 (17) O4—Cd2ix 2.1681 (17)
Cd3—O2iii 2.249 (2) O4—Cd3viii 2.2262 (17)
Cd3—O3 2.3073 (17) O7—Si3vii 1.6529 (16)
Cd3—O8 2.3743 (16) O7—Cd2vii 2.3939 (17)
Cd3—O6 2.4293 (18) O8—Si2vii 1.6399 (17)
Cd3—O9vii 2.4573 (18) O9—Cd1x 2.317 (2)
Cd3—Si3 3.0400 (6) O9—Cd3v 2.4573 (18)
Si1—O3viii 1.592 (2) O9—Cd2vii 2.5102 (18)
O6—Cd1—O1i 86.27 (7) O5—Si1—O7 102.06 (9)
O6—Cd1—O9ii 177.10 (5) O4—Si2—O2 115.78 (11)
O1i—Cd1—O9ii 92.17 (7) O4—Si2—O5 106.92 (9)
O6—Cd1—O2iii 85.40 (7) O2—Si2—O5 109.09 (9)
O1i—Cd1—O2iii 101.21 (8) O4—Si2—O8v 113.60 (10)
O9ii—Cd1—O2iii 92.51 (7) O2—Si2—O8v 107.89 (10)
O6—Cd1—O1 98.08 (7) O5—Si2—O8v 102.69 (9)
O1i—Cd1—O1 175.573 (9) O6—Si3—O9 122.12 (10)
O9ii—Cd1—O1 83.45 (7) O6—Si3—O7v 104.20 (9)
O2iii—Cd1—O1 78.43 (9) O9—Si3—O7v 111.27 (9)
O6—Cd1—O2 98.85 (7) O6—Si3—O8 103.48 (9) O1i—Cd1—O2 78.05 (9) O9—Si3—O8 111.02 (9)
O9ii—Cd1—O2 83.19 (7) O7v—Si3—O8 102.80 (9)
O2iii—Cd1—O2 175.598 (11) Si1—O1—Cd2iii 120.95 (12)
O1—Cd1—O2 101.96 (8) Si1—O1—Cd1iii 126.08 (11)
O4iv—Cd2—O3 108.98 (9) Cd2iii—O1—Cd1iii 97.49 (8)
O4iv—Cd2—O1i 102.47 (8) Si1—O1—Cd1 105.46 (9)
O3—Cd2—O1i 100.15 (8) Cd2iii—O1—Cd1 100.41 (8)
O4iv—Cd2—O7v 108.52 (7) Cd1iii—O1—Cd1 102.54 (9)
O3—Cd2—O7v 88.49 (7) Si2—O2—Cd3i 123.97 (13)
O1i—Cd2—O7v 143.05 (7) Si2—O2—Cd1i 126.20 (11)
O4iv—Cd2—O6 170.92 (7) Cd3i—O2—Cd1i 97.40 (8)
O3—Cd2—O6 76.68 (7) Si2—O2—Cd1 104.50 (9) O1i—Cd2—O6 83.08 (7) Cd3i—O2—Cd1 98.56 (7)
O7v—Cd2—O6 63.92 (6) Cd1i—O2—Cd1 100.98 (9)
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Acta Cryst. (2005). E61, i102–i104
O3—Cd2—O9v 170.71 (7) Si1vi—O3—Cd3 113.65 (8)
O1i—Cd2—O9v 81.13 (7) Cd2—O3—Cd3 109.31 (9)
O7v—Cd2—O9v 85.14 (6) Si2—O4—Cd2ix 135.17 (10)
O6—Cd2—O9v 94.42 (7) Si2—O4—Cd3viii 115.28 (8)
O4vi—Cd3—O2iii 101.60 (8) Cd2ix—O4—Cd3viii 108.69 (9)
O4vi—Cd3—O3 109.03 (8) Si2—O5—Si1 148.03 (13)
O2iii—Cd3—O3 97.36 (7) Si3—O6—Cd1 166.24 (13)
O4vi—Cd3—O8 109.34 (7) Si3—O6—Cd3 95.78 (9)
O2iii—Cd3—O8 145.24 (7) Cd1—O6—Cd3 93.78 (6)
O3—Cd3—O8 87.36 (7) Si3—O6—Cd2 95.40 (9) O4vi—Cd3—O6 172.55 (7) Cd1—O6—Cd2 93.04 (6)
O2iii—Cd3—O6 83.41 (7) Cd3—O6—Cd2 98.03 (7)
O3—Cd3—O6 75.46 (7) Si1—O7—Si3vii 139.89 (11)
O8—Cd3—O6 64.41 (6) Si1—O7—Cd2vii 123.65 (8)
O4vi—Cd3—O9vii 79.62 (6) Si3vii—O7—Cd2vii 96.20 (8)
O2iii—Cd3—O9vii 83.04 (7) Si2vii—O8—Si3 140.61 (11)
O3—Cd3—O9vii 170.97 (7) Si2vii—O8—Cd3 123.15 (8)
O8—Cd3—O9vii 87.25 (6) Si3—O8—Cd3 96.15 (7)
O6—Cd3—O9vii 95.66 (7) Si3—O9—Cd1x 111.27 (11)
O3viii—Si1—O1 115.83 (11) Si3—O9—Cd3v 127.52 (9)
O3viii—Si1—O5 107.63 (9) Cd1x—O9—Cd3v 94.75 (6)
O1—Si1—O5 108.44 (9) Si3—O9—Cd2vii 128.35 (9)
O3viii—Si1—O7 114.32 (10) Cd1x—O9—Cd2vii 94.37 (6)
O1—Si1—O7 107.54 (10) Cd3v—O9—Cd2vii 91.91 (7)