In Situ X-ray Diffraction Studies of the Crystallization of Layered Manganese Thioantimonates(III) under Hydrothermal Conditions

Abstract

The solvothermal synthesis of the layered compound Mn2Sb2S5·DAP (DAP = 1,3-diaminopropane) has been studied using in situ energy-dispersive X-ray diffraction. The results clearly demonstrate that the induction time strongly depends on the reaction temperature. At lower temperatures two crystalline intermediates could be detected. The decay of the second intermediate and the product growth show a strong correlation. A detailed analysis of the extent of reaction α suggests that a small fraction of the intermediate is either dissolved or converted into an amorphous state. The experimentally determined extent of reaction α versus time was compared with various theoretical models. The reaction exponents indicate similar mechanisms for temperatures between 105 and 125 °C. The best agreement is obtained with a first-order reaction and/or phase-boundary-controlled mechanisms. A rigorous analysis reveals that it is highly likely that with increasing α the mechanism changes, suggesting consecutive and/or parallel kinetics as the reaction proceeds. At 130 °C and α > 0.75 a three-dimensional diffusion-controlled process dominates.

High‐Throughput and Time‐Resolved Energy‐Dispersive X‐Ray Diffraction (EDXRD) Study of the Formation of CAU‐1‐(OH)2: Microwave and Conventional Heating

“…The induction time (t 0 ) represents the time until a detectable size of product particles was formed. [43] During this time nucleation took place. The reaction time corresponds to the period from the first appearance of a reflection to its maximum intensity.…”

Solvothermal Syntheses of Two New Thiostannates and an In‐Situ Energy Dispersive X‐ray Scattering Study of Their Formation

“…During the last few years we successfully investigated several solvothermal reactions applying time resolved in-situ energy dispersive X-ray diffraction (in-situ EDXRD). [30][31][32][33][34][35][36] This technique facilitates investigations of the influence of different parameters onto the product formation under real reaction conditions. [10,37] The occurrence, growth and decay of crystalline precursors or intermediates can directly be observed which is not possible with ex-situ experiments.…”

Studying the Solvothermal Formation of MoO3 Fibers by Complementary In Situ EXAFS/EDXRD Techniques

“…The reaction was carried out under autogeneous pressure and isothermal conditions in sealable glass tubes as inserts for autoclaves (see Supporting Information). [22,31] The reaction vessel was transferred into the autoclave, and the reaction time was started after a delay time of approximately 1 min. The reaction temperatures were then reached after about 30 s, and X-ray powder patterns were recorded with acquisition times of 120 s. The spectra were evaluated with EDXPow.…”

“…As solvothermal reactions are usually performed in thick-walled reaction containers, sophisticated in situ techniques employing high-intensity synchrotron radiation are required for their direct monitoring. [19][20][21][22] Generally, the development of high-pressure, in situ spectroscopic approaches is a challenging topic of chemistry and materials science. [23] Orientating kinetic studies may also be performed by quenching hydrothermal reactions, but this information is only valid if the recovered material is not affected by any irreversible changes upon cooling and isolation.…”