Crystal System Determination from X-ray Diffraction of Magnetically Oriented Microcrystal Suspensions

Abstract

A procedure for determining the crystal system of a microcrystalline powder is described. In this procedure, in situ X-ray diffraction measurements are performed on a microcrystal suspension oriented uniaxially under static and rotating magnetic fields. This is followed by the classification of the obtained diffraction images using a flowchart proposed in this study. To demonstrate the validity of this procedure, diffraction images were recorded for microcrystalline suspensions prepared from known crystal systems including triclinic (d-arabitol), monoclinic (cellobiose), orthorhombic (l-alanine), tetragonal (urea), trigonal (bismuth, calcite), hexagonal (zinc), and cubic (sodium chloride) systems. The crystals were classified into their respective crystal systems following the proposed procedure. The determined crystal systems for biaxial crystals were consistent with the reported crystal systems of the microcrystalline powders investigated. Herein, determination of the lattice parameters and space groups for the crystal systems is also discussed.

Discrimination of two crystal forms of a DyBa2Cu3O7−δsuperconductor: tetragonal and orthorhombic forms having very close lengths of the axis

“…1. 6 For the orthorhombic form, the magnetic χ 1 , χ 2 , and χ 3 axes are parallel to the crystallographic a , b , and c axes, respectively. Here, we assume χ 1 > χ 2 > χ 3 > 0.…”

“…9 A set of recorded 2D patterns (with and without rotation) enables us to distinguish the crystal form of the samples. 6…”

“…It is known that the tetragonal and orthorhombic forms can be easily distinguished in 2D (two-dimensional) XRD patterns obtained from the magnetic orientation of the microcrystals in the suspension. 6 In this study, this technique is used to analyze the sample.…”