Buy article online - an online subscription or single-article purchase is required to access this article.
Download citation
Download citation
link to html
The structure of Sigma-2 ([Si64O1 28].4C10H17N), a new clathrasil phase, has been determined directly from synchrotron X-ray powder diffraction data using no prior structural information. The high-resolution data were collected at the NSLS in Brookhaven, and then processed through a series of computer programs assembled and modified for this purpose. There are four Si and seven O atoms in the asymmetric unit, and nine of the 11 framework-atom positions appeared in the direct-methods solution. Eight of these were used to generate a Fourier map which clearly showed the remaining three oxygen positions. A whole-pattern refinement in the space group I41/amd [a = 10.2387(1) and c = 34.3829(1) Å] converged with RF = 0.100, Rwp = 0.225 and Rexp = 0.190. The designation SGT for this new zeolite structure type has been approved by the IZA Structure Commission. Neither of the two cages which make up Sigma-2 has been encountered previously. The 1-aminoadamantane used in the synthesis was found to be disordered in the large cage. The JCPDS Diffraction File No. is PDF39-2000.

Subscribe to Journal of Applied Crystallography

The full text of this article is available to subscribers to the journal.

If you have already registered and are using a computer listed in your registration details, please email support@iucr.org for assistance.

Buy online

You may purchase this article in PDF and/or HTML formats. For purchasers in the European Community who do not have a VAT number, VAT will be added at the local rate. Payments to the IUCr are handled by WorldPay, who will accept payment by credit card in several currencies. To purchase the article, please complete the form below (fields marked * are required), and then click on `Continue'.
E-mail address* 
Repeat e-mail address* 
(for error checking) 

Format*   PDF (US $40)
In order for VAT to be shown for your country javascript needs to be enabled.

VAT number 
(non-UK EC countries only) 
Country* 
 

Terms and conditions of use
Contact us

Follow J. Appl. Cryst.
Sign up for e-alerts
Follow J. Appl. Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds