ion calculator is a free Android application developed by Arash Gholami that is designed to help students learn how to combine anions and cations in chemistry. It is a simple and useful tool for anyone who wants to memorize the different combinations of cations and anions. The application presents a complete list of 35 cations and 45 anions to choose from.

To use the app, the user needs to select a cation and an anion, then press the plus sign to combine them. The application generates the result, and the user can view the complete list of 1575 possible combinations. The interface is straightforward and easy to navigate, making it a convenient tool for students studying chemistry.