Crystal-structure prediction of pyridine with four independent molecules

Abstract

A crystal-structure prediction study with up to four independent molecules in all 230 space groups was undertaken for pyridine with a dispersion-corrected density functional theory method. The two known polymorphs, P2₁2₁2₁ with Z′ = 1 and Pna2₁ with Z′ = 4, were found as ranks 1 and 2 in the correct stability order at low temperature. A pressure scan correctly predicts that the P2₁2₁2₁ form is favoured under pressure. The completeness of the structure generation and the number of hypothetical crystal structures per energy interval are analysed as a function of Z′.