Crystal Habit Prediction

What Is Crystal Habit Prediction?

The morphology of crystals is often polyhedral, including block, sheet, rod or needle, and the corresponding crystal morphology is called crystal habit. Crystal habit prediction is the process of using computational methods to predict the morphology or shape of a crystal based on its chemical structure and growth conditions. It involves understanding the mechanism of crystal growth and the factors that affect crystal shape, such as temperature, pressure, solution concentration and pH. This information can then be used to create models and simulations to predict crystal morphology and size, etc., which helps in the design and optimization of subsequent crystal growth experiments and post-processing procedures.

Crystal Habit Prediction of Small Organic Molecules [1]

What We Do in Crystal Habit Prediction

Based on our powerful computational chemistry platform and mature computational experts, Alfa Chemistry combines a variety of crystal growth models and computational tools to provide crystal habit prediction services for polymorphic substances to accelerate your pharmaceutical solid-state chemical research. Our crystal habit prediction services include:

• Using molecular simulations to predict drug crystal growth mechanisms. For example, to simulate the adsorption of solvent molecules on characteristic crystal planes.
• Predict the variability and controllability of crystal habit under specific reaction conditions, such as solvent type, supersaturation, temperature and additives.
• Morphological prediction of vapor grown crystals, by methods such as Surface Docking, Build-In or Winn and Docherty.
• Calculate the growth rate of the crystal plane through the crystal growth mechanism, such as the helical growth mechanism model and the 2D nucleation growth model.
• Realize all kinds of calculations required for crystal habit prediction through advanced calculation tools, such as finding periodic bond chains, and calculating helical growth lines, etc.

Prediction of Naphthalene Crystal Shape [2]

Crystal Habit Prediction Calculation Methods

• Electronic Structure Method
  The method is based on the laws of quantum mechanics and derives the relevant properties of molecules (such as energy) by solving the Schrödinger equation. Typical electronic structure methods include ab initio, semi-empirical, and density functional theory (DFT).
• Molecular Mechanics Method
  The method is based on the laws of classical physics and consists of a potential energy equation, a series of atom types and parameter sets.
• Hartman-Perdok (HP) Theory
  The crystal habit is caused by differences in the growth rates of the crystal planes. Equilibrium crystal morphology can be determined by calculating the attachment energy.
• Gibbs-Wulff Calculation Method
  The equilibrium shape of the crystal is predicted by calculating the surface energy of each crystal plane.
• Frank-Chernov Calculation Method
  The steady-state shape of the crystal is predicted by calculating the growth rate of each crystal plane.

Choose Alfa Chemistry

Drawing on years of experience in crystallography, Alfa Chemistry has developed state-of-the-art platforms that allow us to accurately predict the crystal habit of drug molecules to optimize your drug development process. Contact us today to learn more about how we can help accelerate your crystallization process.

References

• Carl J. Tilbury, et al. Cryst. Growth Des., 2016, 16, 5, 2590-2604.
• Jinjin Li, et al. Progress in Materials Science, 2016, 82, 1-38.
• C. Schmidt, et al. Journal of Crystal Growth, 2012, 353, 1, 168-173.