Overview
Contact Info
CheXray Instrumentation
Steps to Become a CheXray Facility User
Publication and Co‐authorship Policy
Overview
The Small Molecule X-ray Crystallography Facility (a.k.a. CheXray) is a full service and user facility. We can provide you with all services related to the X-ray diffraction of single crystals and powders of small molecule compounds. Typically, X-ray diffraction is used to determine the solid-state molecular structure at the atomic level of crystalline samples, including absolute stereochemistry of chiral compounds. The facility currently houses state-of-the-art single crystal and powder X-ray diffractometers (see below for specific information about each instrument).
We also provide computational facilities for the analysis of data and are the Colleges distribution point for the Cambridge Structural Database. Training for new users on the single crystal diffractometers occurs through CHEM 208, which is offered in the Spring semester. If you have prior experience in operating a single crystal diffractometer and have taken the CHEM 208 equivalent course at another institution, the CHEM 208 requirement is waved. Users interested in operating the powder diffractometer are not required to take CHEM 208, either. See below for more information on becoming a facility user.
Contact Info
Nicholas Settineri, Director
nsettine@berkeley.edu
BG 5 Giauque
CheXray Diffractorium
B34 Hildebrand Hall
(510) 643-4536
CheXray Instrumentation
Rigaku XtaLab P200 (ChexTWOFACE: RUA #1082)
X-ray Source: MicroMax 007HF Dual Rotating Anode (Cu/Mo-Kα radiation)
Goniostat: 4-circle Kappa Geometry
Detector: Pilatus3 R 200K-A Shutterless Detector
Low Temperature Device: Oxford Cryostream 700 (90-293 K; 0.1 K resolution)
Sample Recommendations:
Organic, organometallic and protein crystals – ideal for absolute stereochemistry determinations
or high-resolution studies. Face indexing available.
Crystal size: 10-100 microns
Rigaku Miniflex 6G Benchtop Powder XRD (ChexFLEX: RUA #2172)
X-ray Source: Sealed Source Tube (Cu-Kα Radiation)
Goniostat: θ/2θ System
Detector: HyPix-400MF Hybrid Pixel Array 0D/1D/2D Detector
Low Temperature Device: None
High Temperature Device: Anton Paar BTS 500 Heating Stage (RT – 500 °C)
Sample Recommendations:
Powders and other materials for general Powder XRD studies.
Steps to become a CheXray Facility User
- Take Radiation Producing Machine Training at UC Learning Center online:
- Log in to blu.berkeley.edu.
- After logging in, "UC Learning Center" is the last listing under self‐service in the left hand column ‐ click on the "UC Learning Center" link to see the catalog.
- Type "EHS 401.2" into the search box at the top of the catalog page and click search.
- Search results will be listed – you should have one result "EHS 401.2 Radiation Safety Trainin for Users of Radiation Producing Machines." Click the "Start" button and complete the training.
- Fill out and submit forms to be added to CheXray Radiation Use Authorizations:
- Obtain and fill out the RUA New User form from Dr. Settineri and return via email.
- Begin facility training:
- Once you have been added to the appropriate instrument RUA, you may begin training to use the facility under the supervision of Dr. Settineri or an approved facility user in your research group. If you are a graduate student looking to use the single-crystal instrument, it is highly recommended you take CHEM 208 first, as you will be trained through this course. If other circumstances apply, please email Dr. Settineri at nsettine@berkeley.edu to schedule training.
- You may not use any of the instrumentation on your own until you go through the instrument check‐out procedure by Dr. Settineri.
CheXray Publication and Co‐authorship Policy
(revised 3/2014)
The following are guidelines you should use in determining whether the crystallographer should be included as a co‐author for a publication or if an acknowledgement is sufficient. These guidelines are in accord with recommendations from the American Crystallographic Association and consistent with co‐authorship guidelines set forth by most academic journals.
Co‐authorship
For facility run service structures: If the structural information derived from the X‐ray diffraction experiment is a critical part of the intellectual content of the paper, then the crystallographer should be considered for co‐authorship on the paper. This includes compounds/structures where other spectroscopy/characterization methods were ambiguous, incomplete or incorrect, structures where absolute stereochemistry was determined and essential to the paper, and structures resulting from crystals that are grown by or in consultation with the facility. The expertise of the facility is available to assist you throughout your publication efforts and our work is not finished with the issuance of the crystal structure report. We will assist with any further analysis requested or required to further enhance the content of the publication. This includes in depth discussions of the metrical data, hydrogen bonding/packing analysis, and similar structure comparisons. We will also work with you to create any additional figures and graphics you may need for publication. The facility would like to review and have the opportunity to give feedback on papers containing structures solved by the facility before the paper is submitted to the journal to check the accuracy of the crystallographic data presented.
For user collected structures: If user collected data requires considerable intervention by the facility in order to obtain a publishable structure, then the crystallographer should be considered for co‐authorship on the paper. This includes crystal cutting, selection and mounting, indexing and detwinning of multi‐component crystals, space group determination and solution of difficult data sets, and refinement of difficult disorder problems. As with service structures above, we will assist in any way we can to enhance the article and minimize any potential issues that may present themselves during the review process related to difficult crystallographic problems.
Acknowledgement
For facility run service structures: If the structural information derived from the X‐ray diffraction experiment is not a critical part of the intellectual content of the paper, then the crystallographer only needs to be acknowledged at the end of the article. This includes compounds/structures where other spectroscopy/characterization methods were unambiguous in identifying the compound and the X‐ray structure is only being used to confirm identity, connectivity, regiochemistry, and/or relative stereochemistry determined by other means. If, in these cases, a crystal structure is crystallographically interesting or novel but not central to the paper at hand, the facility may request to publish the crystal structure separately, as a joint publication with the submitting researcher/PI, in a crystallographic journal after the original article is published as to not undermine the original article.
For user collected structures: If user collected data requires minimal to moderate intervention by the facility in order to obtain a publishable structure, then the crystallographer only needs to be acknowledged at the end of the article. This includes consulting on crystal growth/quality/selection, consulting on indexing/unit cell determination, and consulting on data reduction/structure solution/final refinement/checkCIF errors.