SSZ-31: DO Family

Intergrowth Family SSZ-31

Periodic Building Unit


Periodic Building Unit (PerBU):	SSZ-31 layer

Layer symmetry

2D cell parameters	a = 24.70 Å	b = 8.39 Å	gamma = 90°
Comment	The positions of the double crankshaft chains have been highlighted to facilitate the understanding of the relationships shown in the connectivity pattern table below

References
	Lobo, R.F., Tsapatsis, M., Freyhardt, C.C., Chan, I., Chen, C.-Y., Zones, S.I. and Davis, M.E.
		"A model for the structure of the large-pore zeolite SSZ-31"
		J. Am. Chem. Soc., 119, 3732-3744 (1997)
	van Koningsveld, H. and Lobo, R.F.
		"Disorder in zeolite SSZ-31 described on the basis of one-dimensional building units"
		J. Phys. Chem. B, 107, 10983-10989 (2003)

Connectivity pattern

Examples

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

Symmetry Operation^*	Translation^*	Comment	Image
	+2/6 a
	+1/6 a
	-1/6 a	This is equivalent to +5/6 a or +2/6 a + 1/2 b ^$
	-2/6 a	This is equivalent to +4/6 a or +1/6 a + 1/2 b ^$

^* relative to the previous layer

^$ This equivlancy arises from the fact that the double crankshaft chains are at different positions along b

Note: It would also be possible to translate the layer by 0/6 a or 3/6 a, but this would result in a sequence of 6-6-4-rings in the connecting plane instead of the sequence of 6-5-5 rings seen in the ac-projections above. As this 6-6-4-ring sequence has not yet been observed, it is not included here.


Effect on channel system
	The disorder does not block the 1-dimensional 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).


Polymorph SSZ-31_E

Cell Parameters:	monoclinic	C 1 2/m 1: (# 12)
	a = 24.7010 Å	b = 8.3900 Å	c = 15.0010 Å
	α = 90.0000°	β = 105.5000°	γ = 90.0000°
	Volume =	2995.8 Å³
Framework Density (FD_Si):	18.7

	Ring sizes (# T-atoms):	12 6 5 4
	Channel dimensionality:	Topological (pore opening > 6-ring): 1-dimensional

Maximum diameter of a sphere:
	that can be included	6.54 Å
	that can diffuse along	a: 2.03 Å	b: 5.87 Å	c: 2.04 Å
		[0 1 0] : 5.87 Å
		addional volume data

Composite Building Units:


afi	afs	mel	imf

	Note: This polymorph has NOT been observed as a pure ordered material


Polymorph SSZ-31_F

Cell Parameters:	orthorhombic	C m c a: (# 64)
	a = 8.3900 Å	b = 24.7010 Å	c = 28.9100 Å
	α = 90.0000°	β = 90.0000°	γ = 90.0000°
	Volume =	5991.3 Å³
Framework Density (FD_Si):	18.7

	Ring sizes (# T-atoms):	12 6 5 4
	Channel dimensionality:	Topological (pore opening > 6-ring): 1-dimensional

Maximum diameter of a sphere:
	that can be included	6.37 Å
	that can diffuse along	a: 5.81 Å	b: 2.05 Å	c: 1.76 Å
		[1 0 0] : 5.81 Å
		addional volume data

Composite Building Units:


afi	afs	mel	imf

	Note: This polymorph has NOT been observed as a pure ordered material


Polymorph SSZ-31_G

Cell Parameters:	monoclinic	C 1 2/m 1: (# 12)
	a = 24.7000 Å	b = 8.4000 Å	c = 16.5800 Å
	α = 90.0000°	β = 119.8000°	γ = 90.0000°
	Volume =	2985.1 Å³
Framework Density (FD_Si):	18.8

	Ring sizes (# T-atoms):	12 6 5 4
	Channel dimensionality:	Topological (pore opening > 6-ring): 1-dimensional

Maximum diameter of a sphere:
	that can be included	6.59 Å
	that can diffuse along	a: 2.06 Å	b: 5.84 Å	c: 1.8 Å
		[0 1 0] : 5.84 Å
		addional volume data

Composite Building Units:


afs	lau	mel

	Note: This polymorph has NOT been observed as a pure ordered material


Polymorph SSZ-31_H

Cell Parameters:	orthorhombic	C m c a: (# 64)
	a = 8.3900 Å	b = 24.7010 Å	c = 28.9100 Å
	α = 90.0000°	β = 90.0000°	γ = 90.0000°
	Volume =	5991.3 Å³
Framework Density (FD_Si):	18.7

	Ring sizes (# T-atoms):	12 6 5 4
	Channel dimensionality:	Topological (pore opening > 6-ring): 1-dimensional

Maximum diameter of a sphere:
	that can be included	6.36 Å
	that can diffuse along	a: 5.82 Å	b: 2.05 Å	c: 1.82 Å
		[1 0 0] : 5.82 Å
		addional volume data

Composite Building Units:


afs	lau	mel

	Note: This polymorph has NOT been observed as a pure ordered material