What does ferricyanic mean?
Ferricyanic is a technical adjective used almost exclusively in inorganic chemistry. It describes anything relating to ferricyanic acid, H₃[Fe(CN)₆], or to the salts derived from it, known as ferricyanides. These compounds contain the ferricyanide complex ion, in which an iron atom in the +3 oxidation state is bound to six cyanide groups. Ferricyanic solutions are typically yellow to deep red and act as oxidizing agents in laboratory reactions. The word derives from Latin ferrum, meaning iron, combined with 'cyanic', referring to the cyanide groups attached to that iron centre. Chemists distinguish ferricyanic from the closely similar term ferrocyanic, which refers instead to complexes of two-valent iron; confusing the two changes the chemistry being described entirely. Beyond the laboratory bench, ferricyanide salts have practical roles in photography, blueprints, and electroplating, making the adjective useful shorthand for a well-defined family of iron–cyanide chemistry.
adjectiveOf or relating to ferricyanic acid or its salts (ferricyanides); containing the trivalent iron cyanide complex Fe(CN)₆³⁻.
- Relating to or derived from ferricyanic acid, H₃[Fe(CN)₆], or containing the ferricyanide anion [Fe(CN)₆]³⁻.
"The deep blue precipitate confirmed the presence of ferricyanic ions in the solution."
"A dilute ferricyanic solution turned a striking green when the iron sample was immersed."
"In classical qualitative analysis, ferricyanic reagents were used to test for divalent metal ions."
Swap one letter and you change chemistry history: ferricyanic salts gave photography its blueprint, but their ferrocyanic cousins gave it Prussian blue.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of ferricyanic
The word combines Latin ferrum, meaning iron, with 'cyanic', from Greek kyanos, meaning dark blue, via the cyanide group named for the pigment-forming behaviour of iron–cyanogen compounds. It arose within nineteenth-century chemical nomenclature as chemists systematized the naming of iron cyanide complexes, distinguishing higher-oxidation ('ferricyanic') from lower-oxidation ('ferrocyanic') forms. Cognate terms sharing the same root include ferrous, ferric, and cyanide.
Related word forms
How ferricyanic is actually used
Strictly a technical term of inorganic chemistry; it appears almost exclusively in scientific literature and is unfamiliar to general readers. The corresponding salts are usually named as ferricyanides rather than described with this adjective.
Easily confused with ferricyanic
Ferricyanic refers to compounds of trivalent iron with the Fe(CN)₆³⁻ ion, while ferrocyanic refers to those of divalent iron with the Fe(CN)₆⁴⁻ ion.