Related Experiment Video
Updated: Jun 22, 2026
Crystal Structure of the N-terminal Domain of Ryanodine Receptor from Plutella xylostella
Published on: November 30, 2018
Crystal structure prediction for cyclotrimethylene trinitramine (RDX) from first principles
Rafal Podeszwa1, Betsy M Rice, Krzysztof Szalewicz
1Institute of Chemistry, University of Silesia, Szkolna 9, 40-006 Katowice, Poland.
Crystal structure prediction and molecular dynamics reveal the most stable form of cyclotrimethylene trinitramine (RDX). The study confirms the experimental RDX crystal structure as the lowest energy polymorph, essential for energetic materials research.
Area of Science:
- Computational Chemistry
- Materials Science
- Crystallography
Background:
- Understanding crystal polymorphism is crucial for energetic materials like cyclotrimethylene trinitramine (RDX).
- Accurate prediction of polymorph stability impacts safety and performance.
- Previous methods lacked precision in describing RDX intermolecular interactions.
Purpose of the Study:
- To predict and rank the stability of cyclotrimethylene trinitramine (RDX) polymorphs.
- To validate a new nonempirical potential energy function for RDX dimer interactions.
- To compare computational predictions with experimental crystallographic data.
Main Methods:
- Crystal structure prediction of 500 high-density RDX structures.
- Energy minimization of predicted structures.
- Isothermal-isostress molecular dynamics (NsT-MD) simulations on 14 low-energy polymorphs.
- Validation against experimental crystal parameters and density.
Main Results:
- The lowest-energy polymorph identified computationally matched the experimental RDX crystal structure.
- The experimental polymorph exhibited a lattice energy at least 1.1 kcal mol(-1) lower than other predicted polymorphs.
- NsT-MD simulations accurately reproduced experimental crystal parameters (density, cell edge lengths, cell angles) within 1% and 0.01°, respectively.
- Molecular arrangements in the time-averaged unit cell showed excellent agreement with experimental data (deviations < 0.07 Å for mass centers, < 2.8° for orientation).
- Calculated crystallographic parameters as functions of temperature and pressure showed reasonable agreement with experimental data.
Conclusions:
- The developed nonempirical potential energy function reliably predicts RDX polymorph stability.
- Computational methods, particularly NsT-MD, are effective tools for characterizing energetic materials.
- The findings provide a validated computational approach for understanding and predicting the behavior of RDX crystals.
More Related Videos
06:35Construction and Systematical Symmetric Studies of a Series of Supramolecular Clusters with Binary or Ternary Ammonium Triphenylacetates
Published on: February 15, 2016
11:27X-Ray Crystallography to Study the Oligomeric State Transition of the Thermotoga maritima M42 Aminopeptidase TmPep1050
Published on: May 13, 2020
Related Concept Videos
02:27Predicting Molecular Geometry
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
01:29Determination of Crystal Structures