Automatic sample changer for the analysis of powder samples on an X-ray single-crystal diffractometer equipped with an area detector

A low-budget automatic sample changer that allows the rapid analysis of powder or polycrystalline samples using an X-ray single-crystal diffractometer equipped with an area detector is here described. It uses control software that synchronizes the movement of a linear stage with the collection of frames by the diffractometer. Small pieces of thin solid samples are directly attached to a 30 cm ruler, which is used as a disposable magazine, while loose powder samples are loaded into holes on an acetate strip covered on both sides with Kapton tape and attached to the ruler. The use of this type of diffractometer with a sample changer is a simple, low cost and effective solution for studies requiring the analysis of a large number of samples by X-ray powder diffraction. With the current design up to 30 samples can be measured in a single experiment. The current sample changer was designed so that it can be fitted into a Bruker SMART APEX X-ray single-crystal diffractometer. However, it can be easily adapted to diffractometers from other makers.

Registering pole figures using an X-ray single-crystal diffractometer equipped with an area detector

The orientation of crystals in a polycrystalline sample is adequately described using pole figures, displaying the three-dimensional distribution of specific crystallographic directions or poles. Registration of pole figures is necessary to characterize the preferred orientation of crystals and its influence on the anisotropy of properties in textured materials. It is also useful to understand the development of highly organized microstructures in polycrystalline materials. Pole figures can be registered efficiently using an area detector, available at most modern single-crystal diffractometers. This paper describes in detail the procedure of data collection and processing of pole figures using a single-crystal diffractometer equipped with an area detector. Specifically, a Bruker SMART APEX diffractometer was used, but this methodology can be readily adapted to other diffractometers.

Reversible displacive phase transition in [Ni(en)3]2+(NO3−)2: a potential temperature calibrant for area-detector diffractometers

The coordination complex [Ni(en)3]2+(NO{}_{3}^{- })2(en = 1,2-diaminoethane) undergoes a sharp reversible displacive phase transition at ∼109 K, changing space group fromP6322 above the transition temperature toP6522 below. The phase change is accompanied by a tripling of thecaxis on cooling, resulting in an easy detection of the transition in images from area-detector diffractometers. The transition has been followed using a Nonius KappaCCD and a Bruker SMART APEX CCD. Data sets were collected over the temperature range 100–113 K and integrated using the low-temperature orientation matrix. Reflections withl≠ 3nshow a smooth and rapid decrease in intensity to zero on warming from 106.5 to 111 K. The results are reproducible to within ±2 K in two laboratories and suggest that this compound may be useful as a liquid-nitrogen cryo-calibrant for diffraction instruments equipped with area detectors.