Powder Diffractometer


Dual Source Diffractometer

The Molecular Structure Facility maintains three state-of-the-art CCD-based single-crystal diffractometers and a powder diffractometer in Bragg-Brenatano geometry.

Two of the CCD single-crystal diffractometers are based on a 3-circle Eulerian geometry, while the third instrument is designed around a 4-circle Kappa geometry.

One of the 3-circle diffractometers is a dual-source instrument combining both the rapid data acquisition of a molybdenum X-ray source and a bright, copper micro-focus source. Molybdenum radiation is ideal for a wide-variety of compounds, while copper radiation is ideal for researchers who wish to study the stereochemistry of compounds.

The 4-circle instrument allows the flexibility to access any reflection and is useful for highly specialized experiments.

Nearly all experiments in the facility are performed at low-temperature,120 K for most samples, using a cooled nitrogen gas stream. However, nearly any temperature from 100 to 400 K can be reached.

The powder diffractometer provides a fast, efficient means to verify chemical phases of materials and also to determine if results from single-crystal analyses are consistent with the composition of the bulk solids.

A necessary prerequisite to data collection is crystal selection. Because the crystals are small, ca. 0.008 mm3, they are examined and selected using a stereomicroscope. The facility is equipped with two polarizing stereomicroscopes. One, with a magnification range of 10x to 96x, is outfitted with a digital video camera to allow digital photography of specimens under bright-field, reflected, or polarized illumination.