Related Experiment Video
Updated: May 14, 2026

Synchrotron X-ray Microdiffraction and Fluorescence Imaging of Mineral and Rock Samples
Published on: June 19, 2018
In situ synchrotron diffraction studies on the formation kinetics of jarosites
Nicola V Y Scarlett1, Ian E Grey, Helen E A Brand
1Process Science and Engineering, CSIRO, Clayton South, Victoria 3169, Australia.
Abstract:
This paper reports the results of time-resolved synchrotron powder diffraction experiments where jarosites with different K/H(3)O, K/Na and Na/H(3)O ratios were synthesized in situ at temperatures of 353, 368 and 393 K in order to observe the effect on kinetics and species produced. The Na/H(3)O sample formed monoclinic jarosite at all three temperatures, whereas the K/H(3)O and K/Na samples formed as rhombohedral jarosites at 353 K, and as mixtures of rhombohedral and monoclinic jarosites at the higher temperatures. The relative amount of the monoclinic phase increased with increase in temperature. Unit-cell parameter changes with reaction time could be explained by changes in iron stoichiometry (samples become more stoichiometric with time) together with changes in K/H(3)O and Na/H(3)O ratios. The reaction kinetics have been fitted using a two-stage Avrami model, with two different Avrami exponents corresponding to initial two-dimensional growth followed by one-dimensional diffusion-controlled growth. Activation energies for the initial growth stage were calculated to be in the range 90-126 kJ mol(-1).
More Related Videos
07:26Improving High Viscosity Extrusion of Microcrystals for Time-resolved Serial Femtosecond Crystallography at X-ray Lasers
Published on: February 28, 2019
11:48Microfluidic Chips for In Situ Crystal X-ray Diffraction and In Situ Dynamic Light Scattering for Serial Crystallography
Published on: April 24, 2018
Related Concept Videos
X-ray Diffraction of Biological Samples
According to Bragg's law, when X-rays strike the sample positioned on a stage, the rays are scattered by the electron clouds around the sample atoms. The X-ray diffraction or scattering is caused by constructive interference of the X-ray waves that reflect off the internal crystal...
X-ray Crystallography
Diffraction
Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...
Determination of Crystal Structures
Atomic Absorption Spectroscopy: Atomization Methods
Crystal Growth: Principles of Crystallization
Initiating crystallization involves manipulating the concentration of the solute and the temperature of the solution. Since crystal growth occurs when the ratio of concentration and solubility of the solute in the solvent – the...
Colloidal precipitates