caa a22 4500 378877712 CHVBK 20180305123424.0 cr unu---uuuuu 161128e20030901xx s 000 0 eng 10.1524/zkri.218.9.612.20677 doi (NATIONALLICENCE)gruyter-10.1524/zkri.218.9.612.20677 Dorset Douglas L. Electron crystallography of zeolites. 3. Calcined MCM-22 and MCM-49, a case of subtle differences [Elektronische Daten] [Douglas L. Dorset] Single crystal electron diffraction intensity data, analyzed by direct methods for determining crystallographic phases, have been employed to seek differences between the crystal structures of calcined MCM-22 and MCM-49. A direct comparison of hk0 intensity data indicates such a difference and this is justified further when the respective structural models are refined. The MCM-22 data agree well with the ITQ-1 Si-framework model, but without adding the extraneous interstitial atoms imposed in an earlier powder X-ray diffraction determination. The T-sites in MCM-49 are placed similarly to the ones in MCM-22 but Fourier refinement indicates the presence of an oxygen site not seen for MCM-22. Also one of the oxygen positions found in MCM-22 is not observed in the MCM-49 potential maps. © 2003 Oldenbourg Wissenschaftsverlag GmbH Crystallography nationallicence Inorganic chemistry nationallicence Organic chemistry nationallicence Zeitschrift für Kristallographie - Crystalline Materials De Gruyter Oldenbourg 218/9(2003-09-01), 612-616 2194-4946 218:9<612 2003 218 zkri https://doi.org/10.1524/zkri.218.9.612.20677 text/html Onlinezugriff via DOI 1 research article jats NATIONALLICENCE 856 40 https://doi.org/10.1524/zkri.218.9.612.20677 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Dorset Douglas L. NATIONALLICENCE 773 0- Zeitschrift für Kristallographie - Crystalline Materials De Gruyter Oldenbourg 218/9(2003-09-01), 612-616 2194-4946 218:9<612 2003 218 zkri CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-gruyter