Frequently Asked Questions

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How do I cite CrystalExplorer?

See: How to cite CrystalExplorer

Why does my Licence not work?

The best approach is to cut and paste the licence information directly from the email we sent to you, to minimise any mistakes in copying.

If you still have problems please email us and we'll help.

What are the Licence Conditions for CrystalExplorer?

See: Licence Conditions.

Using CrystalExplorer

Why have the X-H bond lengths changed in my structure?

Neutron Bond Lengths:

C-H 1.083Å
N-H 1.009Å
O-H 0.983Å
B-H 1.180Å

CrystalExplorer normalizes the X-H bond lengths to be the same as those obtained from a neutron diffraction experiments since those obtained from X-ray diffraction experiments are typically several tenths of an Å shorter than the correct lengths.

By normalizing these bond lengths the Hirshfeld surface obtained is independent of the method used to determine the structure and allows meaningful comparisons to be made. Since CrystalExplorer is often used to analyze intermolecular interactions it is especially important to standardize the X-H distances.

Why does CrystalExplorer complain that my structure has an element beyond Xe?

If you want to generate Hirshfeld surfaces or map surface properties on structures containing trans-Xe elements the Clementi-Roetti atomic wavefunctions are insufficient and you must use the Koga-Kanayama-Watanabe-Thakkar wavefunctions. This is now the default set, and if need be it can be chosen in Preferences → Expert → Atomic wavefunction type'.

Why doesn't my CIF load?

Many of the crystallographic programs in use today don't create CIFs that adhere to the standard, and this can cause problems for CrystalExplorer. If you are having problems with your CIF we advise you to run it through the IUCr's CIF checking service and addressing the issues that come up.

Another excellent workaround we have found is to first load up a CIF in Mercury and then resave the CIF. Mercury is very good at dealing with non-standard CIFs and is in general able to convert them correctly.