Wiktionary
n. (context organic compound English) The diamine NH2-CH2-CH2-NH2 that is used in organic synthesis and in the manufacture of polymers
Wikipedia
Ethylenediamine (abbreviated as en when a ligand) is the organic compound with the formula CH(NH). This colorless liquid with an ammonia-like odor is a strongly basic amine. It is a widely used building block in chemical synthesis, with approximately 500,000 tonnes produced in 1998. Ethylenediamine readily reacts with moisture in humid air to produce a corrosive, toxic and irritating mist, to which even short exposures can cause serious damage to health (see safety).
Usage examples of "ethylenediamine".
Now, if you knew the ions were lead, for instance, you could flush out your plumbing simply by using a chelating agent like ethylenediamine tetraacetate.