Microdiffraction as a tool for crystal structure identification and determination

Crystal structure determination of nanolaminated Ti5Al2C3 by combined techniques of XRPD, TEM and ab initio calculations

“…3 It is well acknowledged that the symmetry of a crystal can be directly observed through the strong dynamical diffraction effects using CBED [23]. Thus the CBED technique is a powerful tool to determine the space group of an unknown phase [23,24]. To uniquely determine the space group of Ti 5 Al 2 C 3 , zone-axis patterns were recorded at various camera lengths and different convergence semiangles, as presented in Fig.…”

Morphological, structural and electrochemical properties of lithium iron phosphates synthesized by Spray Pyrolysis

“…X ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution electron microscopy (HRTEM) and selected area electron diffraction (SAED) were used. Crystallographic phases were determined by combining the XRD and the electron diffraction-HRTEM techniques, using the Morniroli procedure [17]; HRTEM images were performed using the digital micrograph TM program.…”

High-pressure synthesis, structural and complex magnetic properties of the ordered double perovskite Pb2NiReO6

“…At this point, in order to shed light into the space group of these compounds, we have studied the symmetry by means of Zone Axis Microdiffraction Patterns (ZAP). It is well known that, microdiffraction patterns obtained with a covergent electron beam allows one to obtain direct information about the crystal system and the Bravais lattice and to reveal the presence of glide planes and screw axes of a specimen 30 . Therefore, one can distinguish the Bravais lattice, between I2/m and Pbnm (or P2 1 /n) space groups, taking into account the relative positions of the reflections in high-order Laue zones (HOLZ) compared to those in the zero-order Laue zone (ZOLZ).…”

“…As a result, this periodicity difference is consistent with an I-centered lattice; therefore, we are in the position to unambiguously establish that I2/m is the correct space group for these Pb 2 NiReO 6 perovskites. Moreover, the mesh of reflections of the FOLZ (m symmetry) and the ZOLZ (2mm symmetry) are characteristics for 2/m point group and fit with I2/m space group determination 30 . Taking this result into account, the Rietveld refinement of the X-ray diffraction data, shown in Figures 1a and 1b, were performed using the monoclinic I2/m space group.…”