Introduction

PyXtal is an open source Python package for generating random crystal structures based on symmetry constraints. The package allows for generation of both atomic and molecular crystals, with both general and special Wyckoff positions. These structures can be output to cif files for optimization and study. The package also allow users to easily access information symmetry group data. See the documentation for information about installation and usage.

Codeveloped by Qiang Zhu and Scott Fredericks at UNLV department of Physics. Distributed under the MIT License.

Current Features:

• Random generation of atomic (3D, 2D, and 1D) crystals and point group clusters for a given symmetry group and stoichiometry
• Random generation of (rigid) molecular crystals (3D, 2D, and 1D), with special Wyckoff positions. Molecules in special Wyckoff positions are automatically oriented to preserve the space group symmetry
• Structure output to cif or POSCAR files via pymatgen
• Easy access to symmetry group information, including Wyckoff positions, site symmetry operations, and point group symbols

Dependencies:

• SciPy 1.0.1
• NumPy 1.14.3
• Pandas 0.20.3
• Pymatgen 2017.9.3
• SpgLib for Python 1.9.9.44

Optional:

• openbabel 2.4.1 (Python bindings) (allows for additional molecule file formats)