Related Experiment Video
Updated: Jun 8, 2026
06:35
Construction and Systematical Symmetric Studies of a Series of Supramolecular Clusters with Binary or Ternary Ammonium Triphenylacetates
Published on: February 15, 2016
Crystal structure prediction and isostructurality of three small molecules
Aldi Asmadi1, John Kendrick, Frank J J Leusen
1Institute of Pharmaceutical Innovation, University of Bradford, Richmond Road, Bradford, BD7 1DP, UK.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|September 22, 2010
Summary
Crystal structure prediction (CSP) for related organic molecules was improved using tailor-made force fields (TMFFs). TMFFs accurately predicted experimental crystal structures, aiding in the discovery of potential new polymorphs.
Area of Science:
- Solid-state chemistry
- Computational materials science
- Crystallography
Background:
- Crystal structure prediction (CSP) is crucial for understanding material properties.
- Developing accurate force fields is essential for reliable CSP.
- Non-transferable force fields offer molecule-specific accuracy.
Purpose of the Study:
- To investigate the efficacy of tailor-made force fields (TMFFs) for CSP of small organic molecules.
- To compare the accuracy of TMFFs against a hybrid density functional theory (DFT) method.
- To explore the potential for discovering new polymorphs using TMFF-guided CSP.
Main Methods:
- Construction of molecule-specific TMFFs using dispersion-corrected DFT (hybrid method) reference data.
- Force field parameter fitting to hybrid method energies and forces.
- Structure generation and ranking using TMFFs, followed by re-optimization with the hybrid method.
- Exploration of a general TMFF (GTMFF) for simultaneous fitting across multiple molecules.
Main Results:
- TMFFs successfully identified experimentally observed crystal structures among the most stable packings for two out of three compounds.
- Re-optimization with the hybrid method showed good agreement with experimental structures, with minor rank changes.
- TMFFs demonstrated higher accuracy in predicting average structural deviation compared to the hybrid method.
- A GTMFF provided sufficient accuracy for CSP, though slightly less precise than individual TMFFs.
- Isostructural analysis revealed a potential, unobserved polymorph for one compound.
Conclusions:
- TMFFs are effective tools for enhancing the accuracy of crystal structure prediction for related organic molecules.
- The TMFF approach aids in validating and refining predicted crystal structures.
- CSP studies using TMFFs can guide experimental efforts towards discovering novel polymorphs.
Related Concept Videos
01:29Determination of Crystal Structures
In the late 1800s, the revelation that light extended beyond visible wavelengths led to the discovery of X-rays by Wilhelm Roentgen. Recognized as high-energy electromagnetic radiation with short wavelengths, X-rays prompted exploration into their interaction with crystals. Max von Laue proposed in 1912 that the periodic arrangement of atoms, ions, or molecules in crystals would cause them to diffract X-rays, a hypothesis confirmed through experiments with copper sulfate and zinc sulfide...
02:27Predicting Molecular Geometry
VSEPR Theory for Determination of Electron Pair Geometries
02:42Ionic Crystal Structures
Ionic crystals consist of two or more different kinds of ions that usually have different sizes. The packing of these ions into a crystal structure is more complex than the packing of metal atoms that are the same size.
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
02:00Molecular Models
Physical models representing molecular architectures of chemical compounds play essential roles in understanding chemistry. The use of molecular models makes it easier to visualize the structures and shapes of atoms and molecules.
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
Tetrahedral 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,...
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,...
02:34Structural Isomerism
Isomerism in Complexes
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can be...
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can be...