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Cell Parameters: |
hexagonal |
P 63 m c (# 186) | |
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a = 14.4047 Å |
b = 14.4047 Å |
c = 50.3545Å |
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α = 90.000° |
β = 90.000° |
γ = 120.000° |
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Volume = |
9048.5Å3 |
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RDLS = |
0.0042 |
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Framework density (FDSi): |
15.7 T/1000 Å3 |
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Topological density: |
TD10 = 794 |
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Ring sizes (# T-atoms): |
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Channel dimensionality: |
Topological (pore opening > 6-ring): 2-dimensional |
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Maximum diameter of a sphere: |
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that can be included |
8.44 Å |
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that can diffuse along |
a: 4.9 Å |
b: 4.9 Å |
c: 2.6 Å |
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Accessible volume: |
16.26 %
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Composite Building Units: |
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* Disordered Type Material |
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The Type Material of this Framework Type is disordered. An ordered framwork structure
is given here to facilitate the discription, but no bulk material with this stucture is presently known.
A brief description of the disorder is given below. For more details see the original publication. |
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Brief description of the disorder
The framework of *-SVY can be described as a stacking of the 'MWW-type layer' shown in green on the right. There are two types of disorder present: (1) a disorder in the stacking sequence of the 'MWW-type layers' and (2) a disorder in the arrangement of the two different types of silanol groups on the surface of the 'MWW-typelayers'.
(1) The stacking of the 'MWW-type layers' is mostly ABAB but ABABCBCB-type stacking faults occur quite frequently resulting in in disorder along [001]. Faults of the type AA (MWW-type framework) are not observed.
(2) Two types of silanol groups are present on the 'MWW-type layer' surfaces, a single Si-OH (shown in purple in the green images on the right) and a cluster of 3 Si-OH (shown in red). The ratio between the two different groups is about 1:1. Although the silanol groups in the images are ordered, the arrangement is not actually known, and both groups may occur on both sides of the 'layers' in a random fashion.
Effect of the disorder on the channel system
The channel system within the 'layer' is, of course, not affected by either disorder. The stacking sequence of the 'MWW-type layers' does not affect the diffusion between the 'MWW-type layers', but the specific arrangement of the silanol groups might have an effect.
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Framework images
(click on icon for larger image)
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| | Projection along [100] | Projection along [110] | |
| | Projection along [001] | 'layer' viewed normal to [001] | |
| | Side pocket in 'layer' surfaceviewed normal to [001] | 'layer' viewed normal to [001]
with silanol groups in different colors | |
| projection of 'layer' along [001]
different silanol groups in different colors |
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