This word is typically preceded by potassium or sometimes ammonium, calcium, or even sodium. Does it, perchance, mean there is, for instance, one potassium per manganate? Ah, no, this is a different use of per: it’s the “thoroughly done” sense that has come from the “through” sense of per. We see this in words such as perfect and permute. As to manganate, it is a derived form of manganese, that element word that everyone confuses with magnesium – and the two words do, in fact, come from the same Greek root, magnesia. So anyway, what permanganate is is manganese in its highest oxidation state (thoroughly oxidated) – with four oxygens stuck to each manganese in a neat four-pointed formation reminiscent of a pocket-size tripod.
The sound of this word starts and ends with voiceless stops, but in the middle we have the nasals and the /g/. It seems like something that has a crust but a softer or more malleable inside. Actually, one typically gets permanganates in powdery form, and there’s not much that’s powdery about this word. It kind of lumps up, especially with the stress on the second syllable.
Permanganate has many overtones in its taste: pomegranate, mango, ptarmigan, mongoose, permeate, magnet, permanent, impregnate… But none of them really have the deep purple of its object. And while pomegranates have antioxidant properties, they’re not a match for the strong oxidizing qualities of permanganates, which can make them good aging agents, disinfectants, and – in some uses – explosives. (Which reminds me that grenade comes from the French for pomegranate… but that’s a whole other note.)