TY - JOUR
T1 - Two new three-dimensional twelve-ring zeolite frameworks of which zeolite beta is a disordered intergrowth
AU - Treacy, M. M.J.
AU - Newsam, J. M.
N1 - Copyright:
Copyright 2018 Elsevier B.V., All rights reserved.
PY - 1988
Y1 - 1988
N2 - Zeolite beta, first described in 19671, is an active catalyst and a useful sorbent1. Sorption1,2 and catalytic data 3,4 suggest that the zeolite could possess a three-dimensional 12-ring pore system. Such a pore system suggests technological potential similar to that of faujasite framework materials, but until now the structure of this zeolite has eluded determination. Powder X-ray diffraction patterns comprise both sharp and broad features, indicative of an extensively faulted structure. Here we determine the structure of zeolite beta by high-resolution electron microscopy, electron diffraction and computer-assisted modelling. The zeolite is an intergrown hybrid of two distinct but closely related structures. Both are constructed from the same centrosymmetrlcal tertiary building unit arranged in layers, and both possess three-dimensional 12-ring pore systems. One end member, polymorph A, forms an enantiomorphic pair, with symmetries P4122 and P4322, with a = 12.4 Å and c = 26.5 Å. Polymorpb B, in which the stacking of layers alternates in handedness, is achiral with space group P1 ̄, and a ≃ b = 12.4 Å, c = 14.5 Å, α ≃ β = 73°, γ ≃ 90°. The high density of stacking faults in zeolite beta materials arises because successive layers must interconnect in either a left- or a right-handed fashion, and both modes of linkage occur with almost equal probability.
AB - Zeolite beta, first described in 19671, is an active catalyst and a useful sorbent1. Sorption1,2 and catalytic data 3,4 suggest that the zeolite could possess a three-dimensional 12-ring pore system. Such a pore system suggests technological potential similar to that of faujasite framework materials, but until now the structure of this zeolite has eluded determination. Powder X-ray diffraction patterns comprise both sharp and broad features, indicative of an extensively faulted structure. Here we determine the structure of zeolite beta by high-resolution electron microscopy, electron diffraction and computer-assisted modelling. The zeolite is an intergrown hybrid of two distinct but closely related structures. Both are constructed from the same centrosymmetrlcal tertiary building unit arranged in layers, and both possess three-dimensional 12-ring pore systems. One end member, polymorph A, forms an enantiomorphic pair, with symmetries P4122 and P4322, with a = 12.4 Å and c = 26.5 Å. Polymorpb B, in which the stacking of layers alternates in handedness, is achiral with space group P1 ̄, and a ≃ b = 12.4 Å, c = 14.5 Å, α ≃ β = 73°, γ ≃ 90°. The high density of stacking faults in zeolite beta materials arises because successive layers must interconnect in either a left- or a right-handed fashion, and both modes of linkage occur with almost equal probability.
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U2 - 10.1038/332249a0
DO - 10.1038/332249a0
M3 - Article
AN - SCOPUS:35348905210
SN - 0028-0836
VL - 332
SP - 249
EP - 251
JO - Nature
JF - Nature
IS - 6161
ER -