- The crystals should be produced as slowly as possible to increase the probability of 'good' crystals. 'Good' includes being of a reasonable size, 0.2-0.5mm (less if heavy elements are present), clear and uncracked with well defined edges and faces. Sufficient characterisation should be carried out to verify that, at least, the crystal is not starting material or a previous structure.
- Where the crystals are only stable in their mother liquor, for preference the solvent(s) used should be as non-volatile as possible and non toxic, as the solvent will tend to evaporate during examination.
- As far as possible the sample should be pure.
- Make your sample 'available' i.e. extractable. Narrow bore vials, small numbers of small crystals, especially in excess mother liquor will make extraction difficult, as will screwtops, by introducing grooves at the top of the vial.
- Fill in an application form CRS Application for X-ray Crystal Structure Determination giving chemical, structural, toxicological etc. data about the crystal. If the sample is toxic safe handling procedures should be indicated.
- Deliver to 6.24
Because of the diverse and often unknown chemical, toxicological and radiological nature of the material, contaminated material, typically wipes and microscope slide(s), may be returned as well as the residual 'crystals'.
If you wish to do the data collection yourself it would usually be at weekends. As a first step contact your supervisor to arrange training.