Can an ion ever exist alone or must it always be bonded to another ion? - Quora
Why is a positive ion often surrounded by eight negative ions? - Quora
Tunable ion transport through ultimately small channels - ScienceDirect
Ions, Acids & Bases
IB Chemistry, Chemical Bonding and Structure Notes
Lesson: Ionic Bonds
Chemical Bonds
Chemical bonds, Chemistry of life, Biology (article)
CH104: Chapter 3 - Ions and Ionic Compounds - Chemistry
Ionic Compounds /ExploringOurFluidEarth