* Polar vs. Nonpolar: Iron(III) nitrate is an ionic compound, meaning it's composed of charged ions (Fe³⁺ and NO₃⁻). This makes it highly polar. Hexane, on the other hand, is a nonpolar solvent.

* "Like Dissolves Like": The general rule of thumb is that polar substances dissolve in polar solvents, and nonpolar substances dissolve in nonpolar solvents.

* Strong Interactions: The strong electrostatic attractions between the ions in iron(III) nitrate are much stronger than the weak interactions that could occur between the ions and the nonpolar hexane molecules.

In summary, the significant difference in polarity between iron(III) nitrate and hexane makes them incompatible for dissolving.