Related Experiment Video
Updated: Jul 31, 2025

Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
Phase and Structure Evolution of Dysprosium Carbonate during Hydrothermal Processes in Dy3+-NH4+-CO32- System
Wenrui He1, Zhihong Liu1, Zhiyong Liu1
1School of Metallurgy and Environment, Central South University, Changsha 410083, China.
Abstract:
Rare earth carbonates play a significant role in preparing rare earth oxides. This study examines the structure and composition of amorphous dysprosium carbonate (ADC) precursors produced through chemical precipitation. Next, how the amorphous phase changed throughout the hydrothermal process is analyzed. The precursor is identified as the Dy2(CO3)3·xH2O with spherical morphology (40 nm), as characterized by TEM, XRD, TG-MS, and FT-IR. It was found that ADC will undergo numerous morphological and structural transformations with the progress of the hydrothermal treatment. First, a metastable Dy2(CO3)3·xH2O is formed, and then a stable crystalline basic dysprosium carbonate Dy(OH)CO3 is obtained. The self-assembly of amorphous precursor units results in 1D and 3D structures according to the theory of negative ion coordination. The transformation mechanism of dysprosium carbonate follows Ostwald's rule of stages, where the metastable phase dissolves and recrystallizes to form the stable basic dysprosium carbonate phase.
Related Concept Videos
Phase Diagrams
Crystal Field Theory - Octahedral Complexes
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
Phase Transitions: Sublimation and Deposition
Titration of Polyprotic Base with a Strong Acid
Valence Bond Theory

