Calcium ferrocyanide is an inorganic compound with the formula Ca2[Fe(CN)6].
It is the Ca2+ salt of [Fe(CN)6]4-, ferrocyanide complex ion.
A yellow solid, it is used as a precursor to the pigment Prussian blue.
[1] It was listed in 2012 by the EU as a "Food Improvement Agent".
In the EU, ferrocyanides (E 535–538) were, as of 2018, solely authorised in two food categories as salt substitutes.