Reference Diffraction Patterns, Microstructure, and Pore Size Distribution for the Copper (II) benzene-1,3,5-tricarboxylate Metal Organic Framework (Cu-BTC) Compounds
Winnie K. Wong-Ng, James A. Kaduk, Daniel W. Siderius, Andrew J. Allen, Laura Espinal, Brad Boyerinas, Igor Levin, Matthew Suchomel, Jan Ilavsky, Eric J. Cockayne, Hui Wu
Cu-paddle-wheel-based Cu3(BTC)2 (nicknamed Cu-BTC, where BTC ≡ benzene 1,3,5-tricarboxylate) is a metal organic framework (MOF) compound that adopts a zeolite topology. We have determined the pore size distribution using the Gelb and Gubbins technique, the microstructure using small angle neutron scattering (SANS) and (ultra) small angle X-ray scattering (USAXS\SAXS) techniques, and X-ray powder diffraction reference patterns for both dehydrated d-Cu-BTC (Cu3(C9H3O6)2) and hydrated h-Cu-BTC (Cu3(C9H3O6)2(H2O)6.96) using the Rietveld refinement technique. Both samples were confirmed to be cubic Fm3m (No. 225), with lattice parameters of a= 26.2792 Å, V =18148.31(6) Å3 for d-Cu-BTC, and a = 26.3103(11) Å, and V = 18213(2) Å3 for h-Cu-BTC. The structure of d-Cu-BTC contains three main pores of which the diameters are approximately, in decreasing order, 12.6 Å, 10.6 Å, and 5.0 Å. The free volume for d-Cu-BTC is approximately 71.85 ± 0.05 % of the total volume and is reduced to approximately 61.33 ± 0.03 % for the h-Cu-BTC structure. The d-Cu-BTC phase undergoes microstructural changes when exposed to moisture in air. The reference X-ray powder patterns for these two materials have been determined for inclusion in the Powder Diffraction File (PDF).