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.

Staff

Instruments

 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.

Facility Service Policy and Fees

The basic fee for an ordinary single-crystal X-ray analysis without complications is $600. Extras, such as absorption correction, repeated data collections for poorly diffracting crystals, multiple independent molecules, resolution of disorder in a structure, etc., must be taken into consideration in calculating a reasonable fee. These fees are used to purchase parts and supplies for optimal maintenance of the X-ray facility.

This facility is supported by grants from the National Center for Research Resources (G12 RR003037) and the National Institute on Minority Health and Health Disparities (8 G12 MD007599-27) from the National Institutes of Health.