4. Conclusion

Crystallographers are fortunate enough to know that determining the structure of a single crystal necessarily has a solution. They are greatly aided in their work by fast, relatively inexpensive computers with comfortable memory capacities.

Nevertheless, the utmost vigilance is required.

If the determination of a compound's structure is not complicated by pseudosymmetry, and therefore by correlations between atomic parameters during refinement, or by the existence of disorder which dilutes the electron density, this determination takes one to two hours. The speed of computer processing, which continues to increase year on year, has led to a spectacular evolution which tends to transform structure determination into a matter of routine. However, the occasional user is strongly advised always to check his results with an experienced crystallographer,...