Explanation for the low melting point of zinc nitrate in terms of its lattice energy and electrostatic interactions?

I understand that ionic compounds tend to have higher melting points, but I was surprised to see zinc nitrate having an unusually low melting point. I tried understanding it in terms of lattice energy and the electrostatic interactions between the ions but I don't have a conclusive answer.




Your melting point is not a melting point. Rather it represents the loss of water from a hydrate salt, which commonly occurs at much lower temperature than what would be required to actually liquefy the ions.


Nor does zinc nitrate truly melt at higher temperature; instead it decomposes to an oxide like most other nitrate salts. Thermogravinetric analysis, for instance from Ref. [1](https://doi.org/10.1155/2014/780206), indicates that the process of dehydration and decomposition is complete at 300-400°C.


1. Gregorio, Flores & Carrillo-López, J & López, J. & Martinez, Rafael & Espinosa, Nestor & Rabanal, Maria. (2014). "Structural and Morphological Properties of Nanostructured ZnO Particles Grown by Ultrasonic Spray Pyrolysis Method with Horizontal Furnace." *Advances in Materials Science and Engineering* **6**. 10.1155/2014/780206.


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