Скачать или смотреть Pyrophoric Copper: Thermal Decomposition of Copper Citrate

Copper salts are moderately toxic. They may be aerosolized during decomposition; avoid inhalation.
Open flame is used.
Pyrophoric metals are a fire hazard.

References: (h/t ScienceMadness user Pok)
Gorrie, T., Kopf, P., & Toby, S. (1967). Kinetics of the reaction of some pyrophoric metals with oxygen. The Journal of Physical Chemistry, 1478(4), 3842–3845. Retrieved from http://pubs.acs.org/doi/pdf/10.1021/j...


A previous video describes the preparation of copper citrate. My interest in this compound comes from my search for pyrophoric copper. ‘Pyrophoric’ means that it catches on fire spontaneously. For example, pyrophoric iron can be prepared by heating iron oxalate. This finely powdered iron burns in a shower of sparks when poured into air. Other pyrophoric metals can be prepared in a similar manner. This 1932 book even suggests creating pyrophoric lead for entertainment. However, aerosolized lead and lead oxide isn’t my idea of “Fun With Chemistry” .
Copper oxalate apparently produces copper oxide when heated, but copper citrate is claimed to decompose into pyrophoric metal.
Gentle heating of the hydrated compound gives a sky-blue anhydrous salt. This happens quickly with more aggressive heating. A dark product then appears, and geyser-like gas evolution is visible. The decomposition residue is finely powdered copper metal. This powder will ignite if dumped out while still hot. Poured on paper, it smolders and nearly ignites. Hot copper oxide doesn’t scorch the paper, demonstrating heat alone is insufficient. Cotton also smolders. Once cool, the copper ceases to ignite spontaneously (though it remains flammable).