Intergrowth Family MFI-MEL

1-dimensional stacking disorder

Periodic Building Unit


Periodic Building Unit (PerBU):	pentasil m layer

Layer symmetry	P 1 m (1)

2D cell parameters	a = 19.74 Å	b = 13.14 Å	gamma = 90°
Comment	Adjacent pentasil chains in the layer are related by mirror planes

References
	Perego, G. and Cesari, M.
		"Ordered and Disordered Structures in Borosilicates with a Pentasil-Type Framework"
		J. Appl. Crystallogr., 17, 403-410 (1984)

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	mirror plane shown as a solid line in the example

^* relative to the previous layer


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).


Polymorph MFI

Cell Parameters:	orthorhombic	P n m a: (# 62)
	a = 20.0900 Å	b = 19.7380 Å	c = 13.1420 Å
	α = 90.000°	β = 90.000°	γ = 90.000°
	Volume =	5211.3 Å³
Framework Density (FD_Si):	18.4

	Ring sizes (# T-atoms):	10 6 5 4
	Channel dimensionality:	Topological (pore opening > 6-ring): 3-dimensional

Maximum diameter of a sphere:
	that can be included	6.36 Å
	that can diffuse along	a: 4.7 Å	b: 4.46 Å	c: 4.46 Å
		addional volume data

Composite Building Units:


mor	cas	mfi	mel

In this space group and setting, the PerBUs are stacked along [100]
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 MFI


Polymorph MEL

Cell Parameters:	tetragonal	I -4 m 2: (# 119)
	a = 20.2700 Å	b = 20.2700 Å	c = 13.4590 Å
	α = 90.000°	β = 90.000°	γ = 90.000°
	Volume =	5529.9 Å³
Framework Density (FD_Si):	17.4

	Ring sizes (# T-atoms):	10 8 6 5 4
	Channel dimensionality:	Topological (pore opening > 6-ring): 3-dimensional

Maximum diameter of a sphere:
	that can be included	7.72 Å
	that can diffuse along	a: 5.19 Å	b: 5.19 Å	c: 5.19 Å
		addional volume data

Composite Building Units:


mor	cas	mfi	mel

In this space group and setting, the PerBUs are stacked along [100]
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 MEL

Disorder Example



	Adjacent layers generated by the same connectivity pattern (same basic color) are shown with different shades for clarity There is no blocking of the 3D channel system.