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用x-射线粉末衍射法研究了两种ZSM-5沸石的晶体结构。两者同属Pnma空间群,晶胞参数分别为:5001—a=20.118(?),b=19.923(?),c=13.410(?);5020—a=20.048(?),b=19.884(?),c=13.352(?)。两者基本结构形貌相近,但与5001相比,5020的骨架结构内存在更大的“应力”,因而较易遭到破坏,两种样品的孔道开口直径分别为:5001-正弦形通道5.080—5.650(?),平均5.367(?),直通道5.207—5.390(?),平均5.307(?);5020—正弦形通道5.111—5.655(?),平均5.368(?),直通道4.993—5.404(?),平均5.226(?)。两者正弦形通道开口尺寸和形状十分接近,而直通道开口尺寸和形状有一定差异,这种孔道结构上的差异是二者性能差别的一个不可忽视的原因。
The crystal structure of two ZSM-5 zeolites was investigated by x-ray powder diffraction. Both of them belong to Pnma space group. The unit cell parameters are as follows: 5001-a = 20.118 (?), B = 19.923 ?, c = 13.410 ?; 5020-a = 20.048 ?, b = 19.884? ), c = 13.352 (?). The basic structure and morphology of the two are similar, but compared with 5001, 5020 has larger “stress” in the skeleton structure and is therefore more vulnerable to damage. The diameters of the openings of the two samples are: 5001-sinusoidal channel 5.080 -5.650 (?), An average of 5.367 (?), A straight channel of 5.207-5.390 (?), An average of 5.307 ?, a 5020-sinusoidal channel of 5.111-5.655 ?, an average of 5.368 ?, a straight channel of 4.993-5.404 (?), An average of 5.226 (?). Both the size and shape of the sinusoidal channel opening are very close, but the size and shape of the straight channel opening have some differences. The structural difference of the channel is a reason that can not be ignored.