Resumen de Why Is There Cyanide in my Table Salt? Structural Chemistry of the Anticaking Effect of Yellow Prussiate of Soda (Na4[Fe(CN)6]·10H2O)
Sarina J. Dorazio, Christian Brückner
Yellow Prussiate of Soda (YPS, Na4[Fe(CN)6]·10H2O) is an approved anticaking agent in table salt. Given that it is a cyanide salt, its use as a food additive is surprising. Recent findings on the mode of action of submonoatomic layers of YPS on NaCl crystals to act as an anticaking agent through nucleation inhibition are presented and its low toxicity is rationalized. The molecular mechanics of the anticaking action are relatively easy to understand for students in general chemistry or sophomore inorganic courses as they involve the archetypal cubic sodium chloride crystal structure and simple steric and electrostatic arguments. The molecular-level explanation reinforces the notion of how structure and charge affect the properties of matter and may also serve as entry toward a classroom dialogue of how ionic lattices are formed. A simple naked eye analytical method of detecting YPS on store-bought table salt in the form of the pigment Prussian Blue (Fe4[Fe(CN)6]3·xH2O) can be utilized as a related demonstration, to visualize the presence of YPS in table salt, or a quick laboratory exercise for inorganic chemistry.
