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After crystallization during ionothermal syntheses in phospho­nium-containing ionic liquids, the structure of (NH4)3Al2(PO4)3 [tri­ammonium dialuminum tris­(phosphate)] was refined on the basis of powder X-ray diffraction data from a synchrotron source. (NH4)3Al2(PO4)3 is a member of the structural family with formula A3Al2(PO4)3, where A is a group 1 element, and of which the NH4, K, and Rb forms were previously known. The NH4 form is isostructural with the K form, and was previously solved from single-crystal X-ray data when the material (SIZ-2) crystallized from a choline-containing eutectic mixture [Cooper et al. (2004). Nature, 430, 1012–1017]. Our independent refinement incorporates NH4 groups and shows that these NH4 groups are hydrogen bonded to framework O atoms present in rings containing 12 T sites in a channel along the c-axis direction. We describe structural details of (NH4)3Al2(PO4)3 and discuss differences with respect to isostructural forms. [ABSTRACT FROM AUTHOR]

Zeolites are porous aluminosilicate materials utilized in a variety of sorption, separation, and catalytic applications. The oil refining industry in particular has seen a number of significant advances due to the introduction of new technologies enabled by new zeolites. Of particular importance are zeolites with 10‐ or 12‐membered ring pores, resulting in pore shapes and sizes appropriate for the interaction with small hydrocarbon molecules. Here, the synthesis of a new zeolite UZM‐55 is reported and the idealized structure thereof is presented. The most complex structure solved to date, UZM‐55 possesses a large triclinic unit cell containing 52 T‐sites. The material uniquely contains both 10‐ and 12‐membered ring pores in a single, undulating one‐dimensional channel, the first example in a zeolitic material of multiple delimiting rings in a single channel. This discovery opens new opportunities in shape‐selective adsorption and catalysis. Demonstrated here is the unique adsorption behavior of UZM‐55, shown both experimentally and computationally to adsorb one nonane molecule per unit cell in a linear conformation. A complex tale: The synthesis and structure solution of UZM‐55, the most structurally complex zeolite thus known, is reported. UZM‐55 is the first zeolite structure solved in P1, contains 52 independent T‐sites and a unique, undulating pore channel with both 10‐ and 12‐membered delimiting rings present in the same pore. Computational results show that nonane is adsorbed in a linear conformation with no kink defects within the pore, confirming the n‐nonane experimental results. [ABSTRACT FROM AUTHOR]

A novel method for CO2 delivery to a porous material is reported, wherein a perfluorocarbon containing dissolved CO2 has been used as a pressure-transmitting liquid in a high-pressure single-crystal X-ray diffraction experiment. Pressure causes the gas to be squeezed out of the liquid into the host crystal, monitored via a single-crystal to single-crystal phase transition on uptake of CO2. [ABSTRACT FROM AUTHOR]

An extended series of MIL-53(M)_X metal-organic frameworks (MIL = Materials of Institute Lavoisier; M = Al, Cr, Fe, Sc; X = Cl, CH3, NO2) have been systematically investiaged to explore the impact of the nature of both the metal centre and the functions grafted on to the organic linker on the mechanical behaviour of this family of highly flexible hybrid porous frameworks under the application of an external pressure of up to 3 GPa. The high-pressure X-ray diffraction measurements allowed the characterization of the pressure-induced phase transitions of the hydrated structures, the associated volume changes/pressure transitions, and their mechanical resilience through the determination of their bulk moduli. [ABSTRACT FROM AUTHOR]