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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: Roxo on June 16, 2022, 02:58:06 PM

Title: Finding lattice enthalpy
Post by: Roxo on June 16, 2022, 02:58:06 PM
It is very straightforward to find lattice enthalpy using Born-Haber  cycles for such as NaCl and other ionic compounds of two elements. That got me thinking about more complicated ionic compounds such as sodium sulfate or nitrates etc. I tried looking in my high school textbooks and found nothing (they are full of simple compounds comprised of two elements). I tried Google but really struggled to find any references I could follow up that explains how lattice energies in general are actually calculated for data books and whether Born Haber cycles are used or other methods. My teacher wasn’t very helpful either since it’s not in the exam specification to know how to calculate lattice enthalpy for even such a common compound as sodium nitrate. I am more than happy  to research this myself if someone can point me to helpful textbooks or other references. I have tried splitting the compound into various component parts and constructing BH cycles for the components but I’m not sure this is right.
Title: Re: Finding lattice enthalpy
Post by: Borek on June 16, 2022, 03:37:13 PM
For more complicated compounds it is probably better to follow the Hess' law with some fancy path of steps yielding the crystal. B-H cycle is just a special case of Hess' law, designed for simple ionic compounds.
Title: Re: Finding lattice enthalpy
Post by: jeffmoonchop on June 16, 2022, 03:44:27 PM
You can use Accelrys Materials studio to calculate lattice energy. Check out my paper.

https://pubs.acs.org/doi/full/10.1021/acs.cgd.1c01190