X-Ray Lab Services (UKZN)

(1) Single Crystals
We offer the following single crystal X-ray crystallography services. Selection and mounting of crystal specimens. Rotation and axial photographs. X-ray data collection. Precession photographs. Digital movies of crystals. Face-indexed numerical absorption corrections (when needed). Structure solution and refinement. Full crystallographic report with experimental details, figures, files, and tables of crystallographic data. Charge density data sets (full sphere, highly redundant data set)
(2) Powders
Most of our work involves single crystal specimens. Users needing highly specialized powder analyses should contact our Soil Science Department for powder X-ray diffraction studies. If you present a special case, however, we can do powder samples on the Xcalibur 2 (Mo Ka radiation only). Note that only homogeneous powder samples with at most two chemical components are appropriate for the CCD diffractometer. The data will be in the form of a spreadsheet of integrated intensity vs. 2q and/or d-values. If you want more than this, i.e., plots of the data and peak-fitting, this will cost more.

(3) Costs

The following costs are current for the period February 2008 through February 2009. Please note that there will be a charge for a data collection that yields no publishable solution (i.e., R₁ in excess of 10% due to an intrinsically poor crystal specimen with R_int > 10%).

UKZN Academic Charge Rates:

ROOM Temperature Data & Structure Solution (UKZN)

You are a UKZN user and you need a room temperature data set collected, solved, and refined (if the crystal is of high enough quality):

Cost = R 1500

For all structures solved and refined and taken through publication standard CIF checks, Dr. Stewart will be a co-author on any papers based on such structural data.
If you do not require expert help with solving and refining the data, then Dr. Stewart will simply send you the raw SHELX.INS file and the HKL data file required for solving and refining your structure. No co-authorship by Dr. Stewart is then required.

LOW Temperature Data & Structure Solution (UKZN)

You are a UKZN user and you need a low temperature data set collected (liquid nitrogen as the cryogen), solved, and refined (if the crystal is of high enough quality):

Cost = R 2000

For all structures solved and refined and taken through publication standard CIF checks, Dr. Stewart will be a co-author on any papers based on such structural data.
If you do not require expert help with solving and refining the data, then Dr. Stewart will simply send you the raw SHELX.INS file and the HKL data file required for solving and refining your structure. No co-authorship by Dr. Stewart is then required.

BAD CRYSTALS at any temperature (UKZN)

This is for any data collected on a diffraction quality crystal that yields an unusable data set through twinning, high mosaicity, cracking, or other intrinsic problem (e.g., high internal R):

Cost = R 850

For all bad data sets, Dr. Stewart will simply send you the raw SHELX.INS file and the HKL data file. You still have to pay for machine time.

Non-UKZN Charge Rates:

Service	Academic Users	Commercial Users
Data set only with photographs	R 2000	R 3000
Full structure solution and documents (CIF check report)	R 3000	R 4000
Data collection that affords no solution (bad crystals)*	R 1000	R 1500
Variable temperature data sets**	R 1500	R 1850
Variable temperature data sets with a full solution and documents at each temperature.**	R 1800	R 2700
Powder samples	R 400	R 650
Charge density study (100 K, data set & photographs)	R 2700	R 3600
Note: the charge is for machine time and cryogens. *The total cost is calculated as the cost of the first data set plus a reduced, repeating cost for each subsequent data set at the desired temperatures.

(4) Sample Submission

The correct procedure to follow for sample submission is as follows.

Select the most decent of your crystals beforehand. If they are unstable, suspend them in silicone grease or silicone oil in a sealed vial.
Package the sample container in bubble wrap in a small box.
Download the sample submission form. Fill in the relevant details.
Send your package by courier, internal mail, or in person (PMB users) to our laboratory.
E-mail the sample submission form to Dr. Stewart or send it on a CDRW disk or on paper along with your sample. We must have the sample submission form for accurate record keeping.
For ALL UKZN users, you must follow the above procedure (using the internal mail if you are based in Durban). Please note that you must include an IDR for the correct amount before any work on your crystal sample(s) will be undertaken.
If you send us a sample that is not suitable for X-ray work, the IDR will be destroyed and no charge against your grant levied.

Physical Address

Dr. K. A. Stewart
Office 35
School of Chemistry
University of KwaZulu-Natal
Corner of Golf & Ridge Roads
Scottsville
Pietermaritzburg
3209
South Africa

(5) Data and Payment

Data. Depending on your requested job(s), we will send you either a ZIP file containing all your data by e-mail or, for large quantities of data, a CD by registered mail.

Payment. For non-UKZN users, Dr. Stewart will ask our Technical Manager, Mr. Desai, to invoice you for the service provided. You will therefore get an invoice directly from our University Finance Division which you should pay within a week of receiving it. The money will be processed by our University Finance Division and credited to the X-ray Lab's running expenses cost centre.

All UKZN users must send an IDR with their sample as payment before any work will be undertaken by the XRCL. Payment is up-front! Failure to stick to this rule will result in no service.

Flat Rate Payment. For UKZN users who do 15-20 X-ray structures a year, i.e., heavy users, it is possible to pay up front a flat rate fee. This ensures that the X-ray cost center has operating capital at the start of each year to pay for repairs, e.g., a new X-ray tube (which costs R 35,000). The flat rate fee structure is as follows:

Flat Rate Deal	Service
Rate A = R 27,000	You are covered for 15-20 data sets which you solve and refine yourself. This will suit someone like Prof. Field. No co-authorship by Dr. Stewart required.
Rate B = R 27,000	You are covered for 15-20 data sets which will be solved and refined by Dr. Stewart and pass all CIF Check tests. Co-authorship by Dr. Stewart IS required.

If you choose a flat rate deal, please pay up-front by March 15 of the year covered by the deal. You therefore need to send Dr. Stewart an IDR with your flat rate fee by this cut-off date to secure the deal.

Time Factor. How long will my data set take? This will depend on the crystal sample (weak diffractors require longer exposure times per data frame), the complexity of the experiment, the crystal queue, and how much data processing you want us to do. We normally process paying customers a bit more quickly. For most regular crystals, if the queue is short, a regular data set is around 6-12 h, so we'd probably run the sample overnight and you could thus expect a solution the next day if there are no other problems and you just wanted the data to process yourself.

Crystal Queue. It is very important to note and understand that we offer a first-come first-served service. Dr. Stewart will draw up a dynamic list each week and put crystals in the queue for processing. There is simply no fairer way of processing crystal samples and no "special deals" will be entertained. In this way, no user will be disadvantaged.

Maximum Throughput. When the instrument is in perfect running order (i.e., most of the time) then users should be aware that we cannot process more than two crystals in 24 hours. One crystal will go on at 8h30 am and another at 16h30 pm for the over-night run. In a 5 day week, 9 data sets will be run (maximum).