Why are metal cyanides such as Prussian blue not classified as organometallic compounds?

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periodic table with group numbers and the s, p, d, and f blocks — organometallic compound The periodic table of the elements, displaying the group numbers and the s, p, d, and f blocks. Elements in the shaded area are the metals of organometallic chemistry.

Metal cyanides, such as Prussian blue, are not classified as organometallic compounds because the carbon atoms they contain are not part of an organic group.1

To be considered organometallic, a substance must contain at least one metal-to-carbon bond where the carbon is part of an organic group—typically characterized by carbon-hydrogen (C–H) bonds, such as alkyl or cyclopentadienyl groups. While metal cyanides do feature metal-carbon bonds, the cyanide ion (CN⁻) is inorganic in nature. Consequently, these substances are categorized as coordination compounds rather than organometallic compounds. Similarly, metal carbides are excluded from the organometallic classification for the same reason.123