Based on high resolution experimental X-ray powder diffraction spectra of SRM-2 molecular sieve,the patterns of its polycrystalline structure were indexed,analyzed and simulated by molecular structure analysis software,which provided important information on its crystal structure,such as space group,and crystal lattice parameters. From the known crystal structure parameters, an approximate structure was first assembled and refined with Rietveld method subsequently. Results show that in SRM-2 molecular sieve, a cage is consisted of 48 framework atoms (twelve 4-membered rings, eight 6-membered rings and six 8-membered rings) and a cages are connected by double 8-membered rings with pore diameter of 0. 419 nm. The crystal structure of SRM-2 molecular sieve belongs to cubic crystal system, 123 space groups. Its unit cell parameters are a = 6 = c=l. 511 1 nm,∠α=∠β =∠γ = 90. 00°.%对SRM-2分子筛粉末进行X射线扫描,获得较高分辨率的衍射数据.用分子模拟软件Materials Studio对谱图进行指标化计算,确定晶体所属晶系和空间群.用分子模拟软件中的结构构建和优化工具,构建SRM 2分子筛的初始结构模型,用Rietveld全谱图拟合方法精修晶体结构.结果表明,SRM-2分子筛是由48个骨架原子(12个四元环,8个六元环或6个八元环)构成的α笼通过双八元环连接而成,孔口直径为0.419 nm；SRM-2分子筛晶体属于立方晶系,I23空间群,晶胞参数为:a=b=c=1.511 1 nm,∠α=∠β=∠γ=90.00°.
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