Electron Diffraction Techniques Research Articles

Dose symmetric electron diffraction tomography (DS-EDT): Implementation of a dose-symmetric tomography scheme in 3D electron diffraction

Beam sensitive nanomaterials such as zeolites or metal-organic frameworks (MOF) represent a great challenge for crystallographic structure determination and refinement. The strong electron-matter interaction and the high spatial resolution achievable make electron diffraction the technique of choice for particles of sizes below a micrometer and many different 3-dimensional electron diffraction (3D ED) techniques have been developed in recent years. Nevertheless, beam sensitivity of the samples can lead to the crystal structure being damaged during the data acquisition impeding the determination of its structure. A simple way to reduce beam damage is to lower the dose during the experiment. However, this implies weaker diffraction intensities which can become problematic for the exploitation of the data.In order to obtain complete data sets with strong intensities without damaging the crystals, we developed the dose symmetric electron diffraction tomography (DS-EDT) method, combining the low-dose electron diffraction tomography (LD-EDT) technique with the dose-symmetric tomography scheme known from cryo-EM. In order to reduce the dose on an individual crystal and still obtain enough data for a structure solution and refinement, we partition the dose over several crystals. The individual datasets are then merged in order to achieve the necessary completeness. On two test structures we first show that merging of data from small domains of the reciprocal space is indeed sufficient to obtain reliable data for structure solution and refinement. Second, we show on the beam sensitive manganese formate that high-quality data can be obtained on a few frames while the frames that have suffered from beam damage can still be used to determine the orientation matrix and the unit cell of the crystals. The results from the dynamical refinement on the obtained data show a high accuracy of the atom positions. In this way, DS-EDT can reduce the total dose on an individual crystal by an order of magnitude with respect to the already very dose-efficient LD-EDT.

The structural diversity and properties of NbxMo1-xO2

We synthesized NbxMo1-xO2 series compounds and determined the structure of each component through x-ray diffraction and selected area electron diffraction techniques. For x=0.05, 0.1, 0.2, they possess room temperature MoO2 monoclinic structure (P21/c); for x=0.25, 0.3, they become to body-centered tetragonal structure (I41/a); for x=0.33, 0.6, 0.65, they further turn to TiO2 rutile-type structure (P42/mnm). Nb0.25Mo0.75O2 has transport and magnetic properties similar to those of NbMoO4 as paramagnetic metal. Moreover, the UV–vis spectra indicate the metallic property of Nb0.05Mo0.95O2, Nb0.25Mo0.75O2, and Nb0.6Mo0.4O2. X-ray absorption spectra at the Mo-L3 and Nb-L3 edges present Mo4+/Nb4+ and Mo4+/Nb5+ valence state for Nb0.25Mo0.75O2 and Nb0.05Mo0.95O2, respectively. This means the latter can be descripted as Nb0.05Mo0.95O2+δ with δ = 0.025.

A Fluorescent Three-Dimensional Covalent Organic Framework Formed by the Entanglement of Two-Dimensional Sheets.

Herein, we report the introduction of steric hindrance in molecular building blocks to prevent π···π stacking, thus allowing two-dimensional (2D) covalent organic sheets to form three-dimensional (3D) covalent organic frameworks (COFs) through entanglement. Starting from the rationally designed precursors containing a bulky anthracene unit in the vertical direction, a highly crystalline COF (3D-An-COF) was successfully synthesized. Very interestingly, 3D-An-COF was determined as an entangled 2D square net (sql) structure, and the high-resolution data (1.1 Å) obtained by the continuous rotation electron diffraction technique allowed us to directly locate all non-hydrogen atoms. Structurally, the presence of an anthracene group outside the C2h symmetry plane strongly reduces the π···π interactions and promotes the formation of square entanglements. In addition, 3D-An-COF is fluorescent and can be used as a sensor to detect the trace amount of antibiotics in water. This study provides a new strategy for the structural diversification of 3D COFs and will certainly motivate us to construct more entangled COFs for interesting applications in the future.

Green Synthesis of Novel Antimicrobial ZnO Nanorods

Zinc oxide (ZnO) nanoparticles (NPs) are increasingly used in the diagnosis and prevention of various human infections and diseases. The multi-functional nature of these nanoparticles together with characteristics such as low toxicity and biodegradability, allow their use in a slew of products and applications ranging from biomedical, food and supplement industries, therapeutics and biosensors. ZnO exhibits biomimetic properties enabling biomedical applications, including use as alternatives to pre-existing antibiotics. This study discusses a simple, cost-effective and environmentally sustainable technique for the synthesis of crystalline ZnO nanorods from egg-white or albumin. Single phase nature of the of the engineered nanocrystals was determined using X-ray diffraction (XRD) and selected area electron diffraction (SAED) technique. The morphology of the ZnO nanorods was studied using transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM). The diameter of synthesized ZnO nanorods was determined to be in the range of 20–30 nm. The crystal structure of wurtzite ZnO was discovered by the use of Raman, FTIR, while the surface area (12.8 m2/g) was analyzed by using Brunauer-Emmett-Teller (BET) surface area study. Both gram-positive and gram-negative bacterial strains were used to test the ZnO nanorods’ antibacterial abilities without the need of artificial UV activation. Findings showed that different disease-causing bacteria present in community and hospital settings respond differently to ZnO nanorods’ antibacterial activity. When the concentration of nanorods powder increased, the ratio of bacterial survival dropped, showing an increase in antibacterial activity. The gram-negative strain Pseudomonas aeruginosa was shown to have the maximum antibacterial activity of the ZnO nanorods as compared to other gram-negative and positive bacteria. Eco-friendly and green synthesis of ZnO NPs produce vital multifunctional nanomaterials which possess promising antibacterial properties with more extensive studies may develop drugs for multidrug resistance bacteria.

Four-Dimensional Scanning Transmission Electron Microscopy: Part I: Imaging, Strain Mapping, and Defect Detection

Abstract Four-dimensional scanning transmission electron microscopy (4D-STEM) is a spatially resolved electron diffraction technique that records the electron scattering distribution at each sampling point. 4D-STEM provides researchers with information that can be analyzed in a multitude of ways to characterize a sample’s structure, including imaging, strain measurement, and defect analysis. This article introduces the basics of the technique and some areas of application with an emphasis on semiconductor materials.

The Application of 3D-ED to Distinguish the Superstructure of Sr1.2Ca0.8Nb2O7 Ignored in SC-XRD

Compared to X-rays, electrons have stronger interactions with matter. In electron diffraction, the low-order structure factors are sensitive to subtle changes in the arrangement of valence electrons around atoms when the scattering vector is smaller than the critical scattering vector. Therefore, electron diffraction is more advantageous for studying the distribution of atoms in the structure with atomic numbers smaller than that of sulfur. In this work, the crystal structure of Sr1.2Ca0.8Nb2O7 (SCNO-0.8) was analyzed using single-crystal X-ray diffraction (SC-XRD) and three-dimensional electron diffraction (3D-ED) techniques, respectively. Interestingly, the superstructure could only be identified by the 3D-ED technique, while no signal corresponding to the superstructure was detected from the SC-XRD data. The superstructure in SCNO-0.8 was disclosed to be caused by different tilting of NbO6 octahedra and the displacements of Sr/Ca atoms in the different atomic layers perpendicular to the a-axis. Therefore, the application of 3D-ED provides an effective method for studying superstructures caused by ordered arrangements of light atoms.

Structure of crystalline water ice formed through neon matrix sublimation under cryogenic and vacuum conditions.

Ice I has three forms depending on the stacking arrangements of its layers: hexagonal ice Ih, cubic ice Ic, and stacking disordered ice Isd. Below ∼60K, amorphous water becomes metastable, and the formation of any form of ice I is often implicitly precluded. Using a newly developed low-temperature reflection high-energy electron diffraction (RHEED) technique, we show that crystalline ice with cubic stacking sequences (i.e., ice Ic) formed through Ne sublimation from a solid H2O/Ne (1:1000 ratio) matrix at 13K. The extent of stacking disorder (disordered cubic and hexagonal stacking sequences) in the ice formed by Ne matrix sublimation is smaller than that in vapor-deposited ice Isd prepared at 143K and below the limit of detection of low-temperature RHEED. Dependence of the resulting ice structures on the thickness of the H2O/Ne matrix shows that amorphous water first forms in the early stages of Ne sublimation, and the cubic stacking sequence subsequently takes place. As the cubic ice Ic formed here at a much lower temperature (13K) than previously observed (typically above 78K), Ne matrix sublimation represents a novel route to the formation of cubic ice Ic under low-temperature and low-pressure conditions.

Unveiling the complexity of nanodiamond structures

Understanding nanodiamond structures is of great scientific and practical interest. It has been a long-standing challenge to unravel the complexity underlying nanodiamond structures and to resolve the controversies surrounding their polymorphic forms. Here, we use transmission electron microscopy with high-resolution imaging, electron diffraction, multislice simulations, and other supplementary techniques to study the impacts of small sizes and defects on cubic diamond nanostructures. The experimental results show that common cubic diamond nanoparticles display the (200) forbidden reflections in their electron diffraction patterns, which makes them indistinguishable from new diamond (n-diamond). The multislice simulations demonstrate that cubic nanodiamonds smaller than 5 nm can present the d-spacing at 1.78 Å corresponding to the (200) forbidden reflections, and the relative intensity of these reflections increases as the particle size decreases. Our simulation results also reveal that defects, such as surface distortions, internal dislocations, and grain boundaries can also make the (200) forbidden reflections visible. These findings provide valuable insights into the diamond structural complexity at nanoscale, the impact of defects on nanodiamond structures, and the discovery of novel diamond structures.

Structure evolution of amorphous poly(d-lactic acid) on highly oriented poly(l-lactic acid) film during annealing

Stereocomplex (SC) of poly(lactide)s (PLAs) has attracted much attention owing to its superior properties, and thus been extensively studied for the poly(d-lactide)/poly(l-lactide) (PDLA/PLLA) blend through solution, melt and cold crystallizations. In this work, the structure evolution of layered samples containing an amorphous PDLA layer and a crystalline PLLA layer with highly oriented edge-on α lamellar crystals during annealing at 175 °C has been studied by AFM, electron diffraction and FTIR techniques. It has been found that edge-on PDLA lamellar crystals and both PLA SC edge-on lamellar crystals and flat-on single crystals in shapes of triangular (preferentially) and hexagonal (less pronounced) can form during annealing. The edge-on PDLA and PLA SC lamellar crystals are highly oriented with molecular chains of both PDLA and PLLA parallel to the chain direction of the used PLLA substrate, reflecting the growth of them take place on the crystalline regions of the PLLA substrate. On the other hand, the random orientation of the triangular flat-on SC single crystals with respect to the used PLLA substrate suggests that the growth of them have nothing to do with the oriented PLLA substrate. It is thus conjectured that the formation of SC single crystals is most likely started in the amorphous regions at places with rich loosely folded loops, chain ends, and even free standing random coils of the used PLLA substrate film.

Linker Vacancy Engineering of a Robust ftw-type Zr-MOF for Hexane Isomers Separation.

Discrimination of physically similar molecules by porous solids represents an important yet challenging task in industrially relevant chemical separations. Precisely controlled pore dimension and/or tailored pore surface functionality are crucial to achieve high-efficiency separation. Metal-organic frameworks (MOFs) are promising candidates for these challenging separations in light of their structural diversity as well as highly adjustable pore dimension/functionality. We report here a microporous, ftw-type Zr-based MOF structure, HIAM-410 (HIAM=Hoffmann Institute of Advanced Materials), built on hexanuclear Zr6 cluster and pyrene-1,3,6,8-tetracarboxylate (ptc4- ). Its crystallographic structure has been determined using continuous rotation electron diffraction (cRED) technique combined with Rietveld refinement against powder X-ray diffraction data, aided by low-dose high-resolution transmission electron microscopy (HRTEM) imaging. The compound features exceptional framework stability that is comparable to the prototype MOF UiO-66. Interestingly, the linker vacancies in the pristine MOF structure could be partially restored by post-synthetic linker insertion. Its separation capability of hexane isomers is enhanced substantially upon the linker vacancy engineering. The restored structure exhibits efficient splitting of monobranched and dibranched hexane isomers at both room temperature and industrially relevant temperature.

Linker Vacancy Engineering of a Robust ftw‐type Zr‐MOF for Hexane Isomers Separation

AbstractDiscrimination of physically similar molecules by porous solids represents an important yet challenging task in industrially relevant chemical separations. Precisely controlled pore dimension and/or tailored pore surface functionality are crucial to achieve high‐efficiency separation. Metal‐organic frameworks (MOFs) are promising candidates for these challenging separations in light of their structural diversity as well as highly adjustable pore dimension/functionality. We report here a microporous, ftw‐type Zr‐based MOF structure, HIAM‐410 (HIAM=Hoffmann Institute of Advanced Materials), built on hexanuclear Zr6 cluster and pyrene‐1,3,6,8‐tetracarboxylate (ptc4−). Its crystallographic structure has been determined using continuous rotation electron diffraction (cRED) technique combined with Rietveld refinement against powder X‐ray diffraction data, aided by low‐dose high‐resolution transmission electron microscopy (HRTEM) imaging. The compound features exceptional framework stability that is comparable to the prototype MOF UiO‐66. Interestingly, the linker vacancies in the pristine MOF structure could be partially restored by post‐synthetic linker insertion. Its separation capability of hexane isomers is enhanced substantially upon the linker vacancy engineering. The restored structure exhibits efficient splitting of monobranched and dibranched hexane isomers at both room temperature and industrially relevant temperature.

Molecular engineering metal-organic frameworks as efficient electrochemical catalysis for water oxidation.

Metal-organic framework (MOF) solids with their variable functionalities are relevant for energy conversion technologies. However, the development of electroactive and stable MOFs for electrocatalysis still faces challenges. Here, we design a molecularly engineered MOF system featuring a 2D coordination network based on mercaptan-metal links (e.g., nickel, as for Ni(DMBD)-MOF). The crystal structure is solved from microcrystals by continuous rotation electron diffraction (cRED) technique. Computational results indicate a metallic electronic structure of Ni(DMBD)-MOF due to the Ni-S coordination, highlighting the effective design of the thiol ligand for enhancing electro-conductivity. Additionally, both experimental and theoretical studies indicate that (DMBD)-MOF offers advantages in the electrocatalytic oxygen evolution reaction (OER) over non-thiol (e.g., 1,4-benzene dicarboxylic acid) analog (BDC)-MOF, because it poses fewer energy barriers during the rate-limiting *O intermediate formation step. Iron-substituted NiFe(DMBD)-MOF achieves a current density of 100 mA·cm-2 at a small overpotential of 280mV, indicating a new MOF platform for efficient OER catalysis. This article is protected by copyright. All rights reserved.

Development and applications ofultrafast transmission electron microscopy.

We present a review on the development and applications of the ultrafast transmission electron microscopy (UTEM) at RIKEN. We introduce the UTEM system for the pump-probe TEM observation in a wide temporal range. By combining the UTEM and pixelated detector, we further develop five-dimansional scanning TEM (5D STEM) which provides the ultrafast nanoscale movie of physical quantities in nano-materials, such as crystal lattice information and electromagnetic field, by convergent-beam electron diffraction (CBED) and differential phase contrast (DPC) imaging technique. We show our recent results on the nanosecond-to-microsecond magnetic skyrmion dynamics observed by Lorentz TEM (LTEM) and photo-induced acoustic wave generation in picosecond regime by bright-field TEM and electron diffraction measurements by UTEM. We also show the demonstartion of the 5D STEM on the quantitative time (t)-dependent strain mapping by CBED with an accuracy of 4 ps and 8 nm, and the ultrafast demagnetization under zero magnetic field observed by DPC with 10 ns and 400 nm resolution.

Unsupervised clustering of nanoindentation data for microstructural reconstruction: Challenges in phase discrimination

Automated clustering of input nanoindentation data using a K-means algorithm was performed on dual phase (DP) and high strength low alloy (HSLA) steels with the aim of accurate microstructural classification of the phases present. Electron microscopy and diffraction techniques were used to correlate the clustering result with the microstructure, and for the DP steel an accurate separation of polygonal ferrite, martensite and anomalous indents (i.e. located on grain boundaries or adjacent to martensite islands) was achieved. In direct contrast, K-means did not reveal an accurate separation of the HSLA constituent phases. After comparing the hardness level of selected HSLA grains and the minimum distinguishable hardness level of the DP steel, it is found that K-means input variables should differ from each other by at least 10% in order to achieve reasonable separation of clustering results. Further targeted nanoindentation experiments on polygonal ferrite grain pairs were then performed to investigate the impact of indentation near grain boundaries between two adjacent grains with similar mechanical properties on the K-means clustering analysis. It is shown that the optimal number of clusters could not converge, and consequently, for the HSLA steel and its complex microstructure the limiting factors to obtain a phase classification by using K-means clustering based on nanoindentation input variables are: (i) the influence on the measured hardness in the vicinity of grain boundaries; (ii) the similar mechanical properties of both phases; (iii) the inhomogeneous substructure of granular bainite.

Synthesis and characterization of AsO[(W,Mo)O3]13, a new (6)-intergrowth tungsten bronze (ITB)

Crystals of a new arsenic tungsten-molybdenum oxide, AsO[(W,Mo)O3]13, have been grown through vapour phase transport at high temperature (1123 ​K). The crystal structure was investigated by combining electron and single-crystal X-ray diffraction techniques, electron microprobe chemical analysis and X-ray absorption spectroscopy. Single-crystal XRD yielded the orthorhombic unit-cell parameters a ​= ​25.0895, b ​= ​7.3061, c ​= ​3.9089 ​Å. Although electron diffraction indicated a doubled translation along [001], superstructure reflections were undetectable with X-ray diffraction so that only the average structure (sub-cell) was determined. The most reliable structural model was obtained in the P222 space group (R1 ​= ​6.96%). It exhibits an octahedral framework which forms six-octahedra thick perovskite slabs (PTB) alternated to single hexagonal tungsten bronze (HTB) modules, indicating that the compound corresponds to a (6)-ITB phase. As3+ was found to be disordered on two off-centred, symmetry-related sites into the hexagonal channels with the typical pyramidal AsO3 geometry. This is in agreement with the results of the extended X-ray absorption fine structure that indicate an As–O bond distance of 1.77 ​Å. The ordered distribution of As within the tunnels, likely related to the doubling of periodicity along [001], could not be determined.

Incommensurately Modulated Structure in AgCuSe-Based Thermoelectric Materials for Intriguing Electrical, Thermal, and Mechanical Properties.

AgCuSe-based materials have attracted great attentions recently in thermoelectric(TE) field due to their extremely high electron mobility, ultralow lattice thermal conductivity, and abnormal "brittle-ductile" transition at room temperature. However, although the investigation on the crystal structure of AgCuSe low-temperature phase (named as β-AgCuSe) wasstarted more than half a century before, it is still in controversy yet, which greatly limits the understanding of its intriguing electrical, thermal, and mechanical performance. In this work, via adopting the advanced three-dimensionalelectron diffraction technique, this study finds that the AgCuSe-based materials crystalize in an incommensurately modulated structure with an orthorhombic Pmmn(0β1/2)s00 superspace group. The local lattice distortion in the incommensurately modulated structure has weak effects on the conduction band minimum due to the delocalized and isotropic feature of Ag 5s states, leading to high carrier mobility. Likewise, the inhomogeneous, weak, and anisotropic Ag-Se bonds result in the high degree of anharmonicity and ultralow lattice thermal conductivity. Furthermore, alloying S in AgCuSe reinforces the interaction between the adjacent Ag-Se layers, yielding the "brittle-ductile" transition at room temperature. This work well interprets the structure-performance relationship of AgCuSe-based materials and sheds light on the future investigation of this class of promising TE materials.

Stability of the In-Plane Room Temperature van der Waals Ferromagnet Chromium Ditelluride and Its Conversion to Chromium-Interleaved CrTe2 Compounds

Van der Waals magnetic materials are building blocks for novel kinds of spintronic devices and playgrounds for exploring collective magnetic phenomena down to the two-dimensional limit. Chromium–tellurium compounds are relevant in this perspective. In particular, the 1T phase of CrTe2 has been argued to have a Curie temperature above 300 K, a rare and desirable property in the class of lamellar materials, making it a candidate for practical applications. However, recent literature reveals a strong variability in the reported properties, including magnetic ones. Using electron microscopy, diffraction, and spectroscopy techniques, together with local and macroscopic magnetometry approaches, our work sheds new light on the structural, chemical, and magnetic properties of bulk 1T-CrTe2 exfoliated in the form of flakes having a thickness ranging from few to several tens of nanometers. We unambiguously establish that 1T-CrTe2 flakes are ferromagnetic above room temperature, have an in-plane easy axis of magnetization, and low coercivity, and we confirm that their Raman spectroscopy signatures are two modes: E2g (103.5 cm–1) and A1g (136.5 cm–1). We also prove that thermal annealing causes a phase transformation to monoclinic Cr5Te8 and, to a lesser extent, to trigonal Cr5Te8. In sharp contrast with 1T-CrTe2, none of these compounds have a Curie temperature above room temperature, and they both have perpendicular magnetic anisotropy. Our findings reconcile the apparently conflicting reports in the literature and open opportunities for phase-engineered magnetic properties.

Nanoscale Mineralogical Characterization of Terrestrial and Extraterrestrial Samples by Transmission Electron Microscopy: A Review

Nanoscale minerals (i.e., nanominerals and mineral nanoparticles) in terrestrial and extraterrestrial materials are difficult to characterize because of their small particle sizes, high surface energy, and/or poor crystallization. Transmission electron microscopy (TEM) is a powerful analytical platform for the characterization of minerals at the nano and even atomic scales, and it can determine their morphology through imaging, derive structural information using multiple electron-diffraction techniques, and investigate chemical compositions. Since the 1990s, the application of TEM to the characterization of nanoscale minerals has developed rapidly into a core technique in nanoscale Earth and planetary science (NEPS). This review introduces a brief history and the general principles of TEM, considers detailed methods of preparing specimens for nanoscale mineralogical characterization by TEM, and emphasizes the contributions of TEM to multiple NEPS research fields in recent decades. These contributions are considered from the perspective of nanoscale mineralogical studies of morphology, structure, and chemistry in complex geological materials. Finally, the work provides an outlook on current opportunities to apply TEM methods to nanoscale mineralogical study. This review aims to provide common and practical TEM methods to NEPS researchers and to support the use of TEM for a wide range of applications in nanoscale mineralogy to promote NEPS development.

Synthesis and conjugation properties of alkynyl functionalized salicylidene Ni(II) and Zn(II) phosphine complexes and their use as a precursor for preparation of NiO and ZnO nanoparticles

The complexes of type [Ni(L1/L2 )(PPh3)2/dppe]NO3 (1a-4a) and [Zn(L1/L2 )(PPh3)2/(dppe)]NO3 (1b-4b) [where L1 = 2-((E)-(4-(2-(trimethylsilyl)ethynyl)phenylimino)methyl)-4-(2-(4-bromophenyl)ethynyl) phenol; L2 = 2-((E)-(4-(2-(trimethylsilyl)ethynyl)phenylimino)methyl)-4-(2-(4-methoxyphenyl)ethynyl) phenol; PPh3 = triphenylphosphine; and dppe = 1, 2-bis(diphenylphosphino)ethane] have been synthesized and characterized by elemental analyses, IR, UV–Vis, 1H NMR, and 31P NMR spectral studies. The ancillary phosphine ligands significantly perturb the metal to ligand charge transfer (MLCT) state of Ni(II) and Zn(II) complexes and associated with their electron donating character. The room temperature luminescence is observed for all complexes which corresponds to π→π* ILCT transition with some MLCT character. The second harmonic generation (SHG) efficiency of the complexes was determined by Kurtz-powder technique indicating that all complexes displayed the SHG property. Metal oxide nanoparticles were obtained by calcinations of representative complexes 1a and 4b at 600 °C and are characterized by FTIR, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and selected area electron diffraction techniques.

The synergistic development of electron crystallography and zeolite discovery

During the past decades, the advancement of new electron crystallographic techniques has made important impacts for the discovery of novel zeolites. High-resolution transmission electron microscopy (HRTEM) imaging directly reveals detailed structural features in zeolites, which is especially useful for studying disordered materials. 3D atomic structures of new zeolites are determined by combining HRTEM images along several projections. Electron diffraction techniques have evolved from 2D zonal-axis electron diffraction to 3D electron diffraction (3D ED), which has transformed a TEM into a single nanocrystal diffractometer for structural elucidation. The development of electron crystallography parallels the discovery of novel zeolites, where Corma's research group has played the key role and contributed to at least 30 zeolite frameworks in the Database of Zeolite Structures. Herein, we present how the ITQ zeolite materials developed by Corma's group pushed the development of electron crystallographic techniques, and how the new 3D ED techniques accelerated the discovery of novel zeolites. During the past 7 years, nearly 80% of new zeolite structures have been determined by electron crystallography. Detailed atomic structural information has been revealed from nano- and micrometer-sized crystals of extra-large pore zeolites, disordered zeolites, and low-dimensional zeolites such as nanotubes and nanosheets.