murexide
/mjʊəˈrɛksʌɪd/Chemistry
noun
The acid ammonium salt of purpuric acid, a purple-red crystalline solid used in complexometric titrations; 5,5'-nitrilodibarbituric acid ammonium, C8H8N6O6. Also (more fully murexide colour): the characteristic purple-red colour of this salt.
Origin
Mid 19th century; earliest use found in Robert Thomson (1810–1864), medical officer of health. From German Murexid from classical Latin mūrex + German -id.