The crystal structure of ponazuril has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional theory techniques. Ponazuril crystallizes in space group P21/c (#14) with a = 8.49511(6), b = 12.38696(6), c = 18.84239(17) Å, β = 96.7166(4)°, V = 1969.152(12) Å3, and Z = 4. N–H⋯O hydrogen bonds link the molecules into chains along the a-axis, with a graph set C1,1(6). The powder pattern has been submitted to ICDD for inclusion in the Powder Diffraction File™ (PDF®).
