The mission of the CUNY X-ray Diffraction (X-ray) Facility is to perform single-crystal analyses for the structure determination of molecules, which make up a crystal. This technique is called single-crystal X-ray crystallography. It is the ultimate method for definitive determination of molecular structures at the atomic level for both organic and inorganic compounds. Its uses range from simple identification of compounds to various exotic configuration and conformational studies.
"Bruker-Nonius Single-Crystal X-ray Diffraction System with four computers
Instrument: Bruker-Nonius KappaCCD, equipped with a CCD detector and a liquid-nitrogen low-temperature device, on a Bruker-Nonius FR590 X-ray generator with a molybdenum sealed tube.
Capabilities: The KappaCCD, acquired in 2001, embodies the state-of-the-art technologies for rapid, precise, and accurate data collection even with small crystals. A charge-coupled device (CCD) detector allows many diffraction spots to be collected simultaneously. Molybdenum radiation with a wavelength of 0.7093 Å is energetic and better suited for inorganic compounds containing heavy atoms, such as, technetium and rhenium, to minimize absorption-correction errors."
"Rules of Operation
1. The sample is examined under the microscope to see if it is suitable for single-crystal X-ray analysis.A person submits a sample and fills the CUNY X-ray Facility Submission form with identification of the researcher, affiliation, chemical information, crystallization solvents and methods, a preliminary chemical structure, optical activity, chemical nomenclature of the compound, molecular numbering system, synthetic schemes, etc. The form also asks if the sample should be returned or destroyed after the X-ray analysis.
2. The sample is examined under the microscope to see if it is suitable for single-crystal X-ray analysis.
3. The sample is either accepted for X-ray analysis or rejected as judged from the microscopic information. Many times it is accepted on a conditional basis. The condition is usually that attempts will be made to collect data but nothing is assured that a crystal from the sample will produce a molecular structure. If a sample is accepted, data is collected and then reduced to obtain structure factors, which are used to solve and refine the molecular structure. The final products of the single-crystal X-ray analysis are ORTEP drawing(s) and a CIF file of the molecular structure, which can be used for publication."