کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
74891 | 49103 | 2009 | 6 صفحه PDF | دانلود رایگان |
Single crystals of hexagonal and dihexagonal morphology cancrinites, crystallized in the same batch reaction with sodalite, have been characterized by X-ray diffraction analysis. Although the unit cell values are almost identical, Si–O bond lengths are greater for the di-hexagonal form (1.650 Å vs. 1.624 Å) and the Al–O bond lengths are shorter (1.710 Å vs. 1.724 Å), possibly indicating greater T-site Si–Al disorder in the di-hexagonal form. 27Al–MASNMR also indicates that the hexagonal form contains minor occluded Al(OH)4- ions (as does the co-crystallized sodalite). In addition to forming homogeneous single crystals, the di-hexagonal form frequently occurs as an overgrowth on hexagonal crystals, indicating that it results from a secondary crystallization, possibly coincident with the dissolution of sodalite coincident with the final phase of fractional crystallization.
Journal: Microporous and Mesoporous Materials - Volume 123, Issues 1–3, 1 July 2009, Pages 274–279