1-dimensional stacking disorder
Periodic Building Unit
Periodic Building Unit (PerBU):
MWW layer
Layer symmetry
P (6) m m
2D cell parameters
a = 14.23 Å
b = 14.23 Å
gamma = 120°
References
Smeets, S., Berkson, Z.J., Xie, D., Zones, S.I., Wan, W., Zou, X., Hsieh M.-F., Chmelka, B.F., McCusker, L.B. and Baerlocher, Ch. "Well-defined silanols in the structure of the calcined high-silica zeolite SSZ-70: new understanding of a successful catalytic material" J. Am. Chem. Soc. , 139 , 16803-16812 (2017)
Examples
The layers are stacked along the [001] direction using the following connectivity patterns
2/3 a , 1/3b
The 3-connected T Atoms on the layer surfaces are only half occupied Show this layer
1/3 a , 2/3b
The 3-connected T Atoms on the layer surfaces are only half occupied Show this layer
m
None
Show this layer
* relative to the previous layer
Effect on channel system
The disorder partly blocks the channel system between the layers, but not the one within the layer
Polymorph SSZ-70_A
Cell Parameters:
hexagonal
P 63 /m m c: (# 194)
a = 14.2270 Å
b = 14.2270 Å
c = 49.8060 Å
α = 90.0000°
β = 90.0000°
γ = 120.0000°
Volume = 8730.1 Å3
Framework Density (FDSi ):
16.3
Ring sizes (# T-atoms):
14 10 6 5 4
Channel dimensionality:
Topological (pore opening > 6-ring): 2-dimensional
Maximum diameter of a sphere:
that can be included
7.86 Å
that can diffuse along
a: 4.71 Å
b: 4.71 Å
c: 2.58 Å
[1 0 0] : 4.71 Å
addional volume data
Composite Building Units:
In this space group and setting, the PerBUs are stacked along [001]
Note: This polymorph has NOT been observed as a pure ordered material
Polymorph SSZ-70_B
Cell Parameters:
hexagonal
R -3 m:H (# 166)
a = 14.3962 Å
b = 14.3962 Å
c = 75.5875 Å
α = 90.0000°
β = 90.0000°
γ = 120.0000°
Volume = 13566.8 Å3
Framework Density (FDSi ):
15.7
Ring sizes (# T-atoms):
14 10 6 5 4
Channel dimensionality:
Topological (pore opening > 6-ring): 2-dimensional
Maximum diameter of a sphere:
that can be included
8.43 Å
that can diffuse along
a: 4.93 Å
b: 4.93 Å
c: 2.54 Å
[1 0 0] : 4.93 Å
addional volume data
Composite Building Units:
In this space group and setting, the PerBUs are stacked along [001] Adjacent layers generated by the same connectivity pattern (same basic color) are shown with different shades for clarity.
Note: This polymorph has NOT been observed as a pure ordered material
Polymorph SSZ-70_C
Cell Parameters:
hexagonal
P 6/m m m: (# 191)
a = 14.3900 Å
b = 14.3900 Å
c = 25.1980 Å
α = 90.000°
β = 90.000°
γ = 120.000°
Volume = 4518.8 Å3
Framework Density (FDSi ):
15.9
Ring sizes (# T-atoms):
10 6 5 4
Channel dimensionality:
Topological (pore opening > 6-ring): 2-dimensional
Maximum diameter of a sphere:
that can be included
9.69 Å
that can diffuse along
a: 4.92 Å
b: 4.92 Å
c: 2.6 Å
addional volume data
Composite Building Units:
In this space group and setting, the PerBUs are stacked along [001] Adjacent layers generated by the same connectivity pattern (same basic color) are shown with different shades for clarity
Note: This polymorph corresponds to the ordered framework MWW
There is no blocking of the 2D channel system.