When an ionic compound dissolves in water and becomes ions.

1) Typically we see:

$\ce{AB ->}$ Ions $\ce{A+ + B-}$

$\ce{ABC ->}$ Ions $\ce{AB+ + C-}$

2) But how about the one below, is there any case that will fit the situation

$\ce{ABC2 -> A+ + B+ + 2C-}$

or $\ce{AB2C-> A+ + 2B+ + C^3-}$


Another is the de-icing compound calcium magnesium acetate, $\ce{CaMg2(C2H3O2)6}$ (https://en.m.wikipedia.org/wiki/Calcium_magnesium_acetate). Like all such "double cation salts", this compound has a crystal structure with two different sites for cations; in this case one kind of site has the calcium ions and the other has the magnesium ions. This combination enables a reproducible stoichiometry, but when the crystal structure is broken down by dissolving the salt you just have "ion soup".


Yup, they are definitely possible. Such salts are called as mixed salts. They furnish more than two ions when dissolved in water. A popular example is Mohr's salt, popularly used as a standard titrant to measure concentrations of oxidizing agents. It's (anhydrous) formula is:


This salt on dissolving in water would split as:

$$\ce{Fe^{II}(NH4)2(SO4)2 <=>> Fe^2+ + 2NH4+ + 2SO4^2-}$$

This is one such example. There are many others, notably alums. Alums are a general type of mixed salts, of the form:


where $\ce{A^{I}}$ is a monovalent metal ion, and $\ce{M^{III}}$ is a trivalent metal ion. Clearly, these are also mixed salts.

These are just a few practical examples. There's literally quite nothing that can stop imagination of course.


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