Classical packing and stacking in 6-phenyl-5-azauracil

Although probably not incorporated directly into nucleic acids, the title c ompound, 6-phenyl-1,3, 5-triazine-2,4(1H,3H)-dione (C9H7N3O2), resembles th e pyrimidine bases in such nucleic acids. In the solid state, molecules bas e pair about a centre of symmetry into a dimer arrangement along the a axis and are linked firmly in the c direction by an N1-H1 ... O4 interaction re lated by the glide plane. The remaining intermolecular forces are achieved by the alternate stacking of phenyl and triazine rings in columns along the b axis.