Intergrowth Family CHA-AEI

Periodic Building Unit


Periodic Building Unit (PerBU):	AEI layer

Layer symmetry	C m 1 (1)

2D cell parameters	a = 13.68 Å	b = 12.61 Å	gamma = 90°

References
	Sławinski, W. A., Wragg D. S., Akporiaye D. and Fjellvåg H.
		"Intergrowth structure modelling in silicoaluminophosphate SAPO-18/34 family"
		Microporous Mesoporous Mat., 195, 311-318 (2014)

Connectivity pattern

Examples

The layers are stacked along the [001] direction using the following connectivity patterns

Symmetry Operation^*	Translation^*	Comment	Image
i	None	one inversion center shown as an open circle in the example
m	None	mirrow plane shown as a solid line in the example

^* relative to the previous layer

Types of disorder
There are two types of disorder described in the reference above:
(1) A random stacking of the CHA-AEI layers.
(2) A sequence of smaller homogenous blocks of the two polymorphs.


Effect on channel system
	The disorder does not block the channel system

Simplest ordered end members

The color of each layer reflects the symmetry/translation operation used to generate it from the previous layer (see table above).

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Polymorph CHA

Cell Parameters:	trigonal	R -3 m:H (# 166)
	a = 13.6750 Å	b = 13.6750 Å	c = 14.7670 Å
	α = 90.000°	β = 90.000°	γ = 120.000°
	Volume =	2391.6 Å³
Framework Density (FD_Si):	15.1

	Ring sizes (# T-atoms):	8 6 4
	Channel dimensionality:	Topological (pore opening > 6-ring): 3-dimensional

Maximum diameter of a sphere:
	that can be included	7.37 Å
	that can diffuse along	a: 3.72 Å	b: 3.72 Å	c: 3.72 Å
		addional volume data

Composite Building Units:


	d6r		cha

In this space group and setting, the PerBUs are stacked along [101]
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 CHA

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Polymorph AEI

Cell Parameters:	orthorhombic	C m c m: (# 63)
	a = 13.6770 Å	b = 12.6070 Å	c = 18.4970 Å
	α = 90.000°	β = 90.000°	γ = 90.000°
	Volume =	3189.4 Å³
Framework Density (FD_Si):	15.1

	Ring sizes (# T-atoms):	8 6 4
	Channel dimensionality:	Topological (pore opening > 6-ring): 3-dimensional

Maximum diameter of a sphere:
	that can be included	7.33 Å
	that can diffuse along	a: 3.84 Å	b: 3.84 Å	c: 3.64 Å
		addional volume data

Composite Building Units:


	d6r

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 AEI

Disorder Example



	Alternating light and dark colors have been used to highlight the individual layers.