Related Experiment Video
Updated: Jul 12, 2025
08:55
Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
8.6K
Two-Step Melting in a Bulk Crystal via Intermediate Metastable Liquid
Shi-Yu Liu1, Yao Yu1, Lin Liu1
1School of Materials Science and Engineering, State Key Lab for Materials Processing and Die and Mold Technology, Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China.
The Journal of Physical Chemistry Letters
|October 26, 2023
Summary
Researchers observed a novel two-step melting process in three-dimensional (3D) ibuprofen crystals. This indirect pathway involves an intermediate liquid phase, challenging the traditional one-step melting model in 3D systems.
Area of Science:
- Materials Science
- Crystallography
- Physical Chemistry
Background:
- Melting mechanisms link crystal structure and liquid dynamics.
- Two-dimensional systems exhibit two-step melting via a hexatic liquid phase.
- Three-dimensional melting is traditionally considered a one-step process.
Purpose of the Study:
- To investigate the melting process in a three-dimensional system.
- To determine if a two-step melting pathway exists in 3D.
- To explore the influence of liquid complexity on melting transitions.
Main Methods:
- Utilized (S)-(+)-ibuprofen as a three-dimensional model system.
- Observed the crystal-to-liquid transition pathway.
- Analyzed the properties of intermediate liquid phases and their lifetimes.
Main Results:
- A two-step melting process was identified in three-dimensional ibuprofen.
- An intermediate liquid phase with a remarkably long lifetime was discovered.
- The transition to the ordinary liquid phase occurred at a spinodal point, marked by long-range fluctuations.
Conclusions:
- The study reveals an indirect melting pathway in a 3D system.
- Liquid complexity can influence the melting transition pathway.
- The findings suggest the possibility of continuous melting in three dimensions.
Related Concept Videos
01:10Recrystallization: Solid–Solution Equilibria
1.1K
Recrystallization is a purification technique used to separate impurities from solid compounds. In this technique, no chemical reactions occur. Instead, it exploits physical properties only, specifically, the solubility differences between the desired compound and impurities, either at a single temperature or at different temperatures, and under other selected conditions. The solid-solution equilibrium (solubility equilibrium) of each component in the solution represents a binary phase...
1.1K
02:39Phase Transitions: Melting and Freezing
12.4K
Heating a crystalline solid increases the average energy of its atoms, molecules, or ions, and the solid gets hotter. At some point, the added energy becomes large enough to partially overcome the forces holding the molecules or ions of the solid in their fixed positions, and the solid begins the process of transitioning to the liquid state or melting. At this point, the temperature of the solid stops rising, despite the continual input of heat, and it remains constant until all of the solid is...
12.4K
01:25Crystal Growth: Principles of Crystallization
2.0K
Crystallization is a phase transformation process in which crystals are precipitated from a supersaturated solution or formed from other sources. During crystallization, atoms or molecules arrange themselves into a well-defined, rigid crystal lattice to minimize energy.
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...
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...
2.0K
02:33Phase Transitions: Sublimation and Deposition
17.2K
Some solids can transition directly into the gaseous state, bypassing the liquid state, via a process known as sublimation. At room temperature and standard pressure, a piece of dry ice (solid CO2) sublimes, appearing to gradually disappear without ever forming any liquid. Snow and ice sublimate at temperatures below the melting point of water, a slow process that may be accelerated by winds and the reduced atmospheric pressures at high altitudes. When solid iodine is warmed, the solid sublimes...
17.2K
02:54Molecular and Ionic Solids
17.2K
Crystalline solids are divided into four types: molecular, ionic, metallic, and covalent network based on the type of constituent units and their interparticle interactions.
Molecular Solids
Molecular crystalline solids, such as ice, sucrose (table sugar), and iodine, are solids that are composed of neutral molecules as their constituent units. These molecules are held together by weak intermolecular forces such as London dispersion forces, dipole-dipole interactions, or hydrogen bonds, which...
Molecular Solids
Molecular crystalline solids, such as ice, sucrose (table sugar), and iodine, are solids that are composed of neutral molecules as their constituent units. These molecules are held together by weak intermolecular forces such as London dispersion forces, dipole-dipole interactions, or hydrogen bonds, which...
17.2K
02:32Bonding in Metals
47.4K
Metallic bonds are formed between two metal atoms. A simplified model to describe metallic bonding has been developed by Paul Drüde called the “Electron Sea Model”.
47.4K