(R)‐1‐Phenyl­ethyl­ammonium 6‐amino‐5‐nitro­pyrimidine‐2,4(1H,3H)‐dionate (R)‐1‐phenyl­ethyl­amine hemisolvate: hydrogen‐bonded sheets of ions with pendent solvent mol­ecules

In the title compound, 2C₈H₁₂N⁺·2C₄H₃N₄O₄^?·C₈H₁₁N, the anions are linked by paired N—H?N hydrogen bonds H?N = 2.07 and 2.11 Å, N?N = 2.942 (3) and 2.978 (3) Å and N—H?N = 173 and 170°] and by paired N—H?O hydrogen bonds H?O = 1.98 and 2.05 Å, N?O = 2.855 (3) and 2.917 (3) Å, and N—H?O = 173 and 167°] into chains of rings. These chains are linked into sheets by further N—H?O hydrogen bonds in which all of the donors are provided by the cations H?O = 1.83–2.17 Å, N?O = 2.747 (3)–2.965 (3) Å and N—H?O = 141–168°]. The neutral amine molecule is pendent from the sheet and is linked to it by a single N—H?N hydrogen bond H?N = 2.00 Å, N?N = 2.901 (3) Å and N—H?N = 175°].