Web Resources

WebCSD

This is the online searching page for CCDC database, where you can search by structure, unit cell, etc. Before you attempted to grow/submit your crystals, it is always recommended to search the database to see if the structure has been published.

checkCIF

This is where you run an online checkcif before you submit the data for publication. If your final full data set come from me, you do not need to do this. If you do your own analysis, you must go through this process to make sure your analysis is valid. The suspicious “problems” are flagged as A/B/C/G level alerts. You should try your best to eliminate A and B level alerts. Small amount of certain C level alerts are usually acceptable for most journals. But large amount of C level alerts should be examined carefully as they collectively could indicate some severe problems. Currently this tool is only good for small molecules, but not for large biomolecules.

High-Resolution Space Groups

This webpage provides the space group diagrams and tables for all the 230 space groups. You can find there the symmetry operators/operations, reflection conditions, etc.

3-Dimensional Space Groups

This webpage provides another way of listing the 230 space groups, with some convenient color coding.

Data analysis software

SHELXL

This page is the homepage for SHELXL package, the heart/brain for most of today’s crystallographic programs, esp. for small molecules single crystals. It also finds its use in powder XRD and protein XRD. The package is totally free for academic users. What you only need to do is registration. Once registered, you can download the whole package to your own computer. BTW, this SHELXL package is needed before you can use any of the popular GUI programs, ,such as WinGX, Olex2, Shelxle, etc. This page also have the instructions for all the four letter cards you may use during the refinement process, such as: AFIX, DFIX, TWIN, etc.

PLATON

The Platon program is a powerful third party program which you can call from within some GUI programs (e.g., Olex2). It is very powerful and versatile. To name a few: It can find the missing symmetry (or pseudo symmetry) of your current space group. It can detect unaccounted (non)-merohedral twinning in your data. Bear in mind though it only provides reasonable suggestions. It is up to you to determine if they are valid. You can register and download the package to your local computer. Following the instructions, you can set up such that it can be called from within your favorite GUI program.

Visualization software

Mercury

The Mercury software suite is a popular crystal structure visualization tool for preparing figures for publication in the small molecule community..

VESTA

Visualization for Electronic and STructural Analysis (VESTA) is a free tool popular for viewing solid-state and mineral crystal structures. It supports magnetic structure visualization.