Potassium ferricyanide is the chemical compound with the formula K3[Fe(CN)6]. This bright red salt contains the octahedrally coordinated [Fe(CN)6]3− ion. It is soluble in water and its solution shows some green-yellow fluorescence. It was discovered in 1822 by Leopold Gmelin.
Potassium ferricyanide
Potassium ferricyanide when milled has lighter color
Leopold Gmelin was a German chemist. Gmelin was a professor at the University of Heidelberg. He worked on the red prussiate and created Gmelin's test, and wrote his Handbook of Chemistry, which over successive editions became a standard reference work still in use.
Leopold Gmelin
Gmelin and his wife, portraits by Jakob Schlesinger, 1820
German postal stamp featuring Gmelin
Leopold Gmelin's grave on the Mountain Cemetery in Heidelberg in the Dept. E