# Miscibility of pairwise miscible liquids

If you have a mixture of 3 (or more) liquids which are "pairwise miscible", but which don't react with each other, does that guarantee that the mixture will only have one layer?

By "pairwise miscible", I mean that for every combination of two substances in the mixture, they are miscible with each other, i.e. soluble in all proportions.

For example, ethanol/water/acetone.

• I'll say very probably, but I'd bet that there is a black swan somewhere. – MaxW Dec 12 '15 at 21:36

## 1 Answer

So you want to know whether there is a ternary system with an "island of immiscibility". Well, it turns out that people have thought of this before; such systems have a name ("type 0 systems"), and this paper mentions water/DMSO/THF as an example.