Ion
Jika suatu ion mengandung elektron bebas, ia disebut ion radikal. Seperti radikal tak bermuatan, ion radikal sangat reaktif. Ion poliatomik yang mengandung oksigen, seperti karbonat dan sulfat, disebut oksianion (). Ion molekular yang mengandung sekurang-kurangnya satu ikatan karbon-hidrogen disebut "ion organik". Jika muatan dalam ion organik secara formal terpusat pada suatu karbon, maka ia disebut "karbokation" (jika bermuatan positif) atau "karbanion" (jika bermuatan negatif).
Asam poliprotik
Asam triprotik (HA) dapat mengalami satu, dua atau tiga disosiasi dan memiliki tiga konstanta disosiasi, di mana "K" > "K" > "K".
An inorganic example of a triprotic acid is orthophosphoric acid (HPO), usually just called phosphoric acid. All three protons can be successively lost to yield HPO, then HPO, and finally PO, the orthophosphate ion, usually just called phosphate. An organic example of a triprotic acid is citric acid, which can successively lose three protons to finally form the citrate ion. Even though the positions of the protons on the original molecule may be equivalent, the successive "K" values will differ since it is energetically less favorable to lose a proton if the conjugate base is more negatively charged.