Table of Contents
Physics Research International
Volume 2016, Article ID 3537842, 5 pages
Research Article

Polymorphs of Tolfenamic Acids: Stability Analysis Using Cluster Method

1Faculty of Applied Sciences, Universiti Teknologi MARA, 02600 Arau, Perlis, Malaysia
2Computational Chemistry and Physics Laboratory, School of Distance Education, Universiti Sains Malaysia, 11800 Pulau Pinang, Malaysia

Received 2 October 2015; Revised 2 March 2016; Accepted 14 March 2016

Academic Editor: Ravindra R. Pandey

Copyright © 2016 Lee Sin Ang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


We report results of the relative stability between form I and form II of tolfenamic acid. By performing systematic cluster calculations at the B3LYP/6-31 level of theory and including the corrections to the dispersion and basis set superposition error, we found that form II is energetically more stable than form I. Furthermore, we found that the formation of dimers has a stabilizing effect compared to individual monomers in the clusters that we have considered.