Ammonium purpurate, the ammonium salt of purpuric acid, made use of as a complexometric signal and a colorimetric reagent.
A crystalline nitrogenous material (C8H8N6O6, 5-5'-nitrilodibarbituric acid monoammonium salt) having an outstanding dichroism, being green by reflected light and garnet-red by transmitted light. It had been previously used in dyeing calico, and ended up being acquired in a big quantities from guano. It is now synthesized from alloxan. Previously called additionally ammonium purpurate.
The purpurate of ammonia of Prout (probably C8H8N6O6).