what are the refined parameters of commercially available basolite z1200? Please send me any useful article to understand all this as soon as possible.
several different space group ZIF-8 files are available how to choose the right one?
Is that wykoff factor is responsible to choose the refinement?
Please respond on urgent basis.
Thank you
The reason is very likely pseudosymmetry. Of cause, there is actually only one phase correct (phase diagram) but as typical for experimental techniques, limitations exist which are sometimes difficult to reduce. Some are related to contaminations/polutions which changes the stability toward another modification. They can be clearly different so that they are easy to discriminate but sometimes the differences are that small that some people simply publish "wrong" data. In order to see the differences, you should compare the theoretical diffraction patterns. If they are clearly different, the phases are really different. If not not, the small deviations are more theoretically important. Then use the high-symmetric since the lower symmetry is obviously not easy to handle.
Wyckoff positions also express this like 0,0,0.25 and 0,0,0.245. The first possibly expresses a position of higher local symmetry. The second does not and has then usually a higher multiplication which requires a theoretical reduction of this value by a lower occupation, e.g. 0.5. This is all dependent on the space group symmetry or subgroup relationship. You can learn more about this reading International Tables of Crystallography, Vol. A1. But do not expect, that you understand the entire business after a single article. You might catch the principle, but there are scientists who did this their entire life...and even they only scratched the importance of these effects.
And don't believe a database. They only collect data and publish them. Databases are full of errors which are not yet discovered by tools developed in order to discover obvious errors.
- Badges
- Science topic
- Similar topics
- Filing