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A tangent formula derived from Patterson-function arguments. III. Structure determination of zeolitic and layered materials from low-resolution powder diffraction data (1995)

Rius, J. ; Sañé, J. ; Miravitlles, C. ; [et al.]

[S.l.] : International Union of Crystallography (IUCr)

Acta crystallographica 51 (1995), S. 840-845

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ISSN: 1600-5724

Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001

Topics: Chemistry and Pharmacology , Geosciences , Physics

Notes: The viability of solving the structure type of zeolitic and layered materials applying multisolution direct methods to low-resolution (2̃.2 Å) powder diffraction data is shown. The phases are refined with the tangent formula derived from Patterson-function arguments [Rius (1993). Acta Cryst. A49, 406–409] and the correct phase sets are discriminated with the conventional figures of merit. The two test examples presented are (a) the already known tetragonal zeolite ZSM-11 (space group 1{\bar 4}m2) at 2.3 Å resolution and (b) the hitherto unknown layer silicate RUB-15 (Ibam) at 2.2 Å resolution. In both cases, the tetrahedral Si units appear as resolved peaks in the Fourier maps computed with the phases of the highest-ranked direct-methods solutions.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1107/S0108767395005800

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Structure analysis and general characterization of the fluorogallophosphate Mu-2: A new microporous material built from double-four-ring units hosting F− anions (2000)

Reinert, P. ; Marler, B. ; Patarin, J.

Springer

Journal of materials science 35 (2000), S. 2965-2972

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ISSN: 1573-4803

Source: Springer Online Journal Archives 1860-2000

Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Notes: Abstract A new three-dimensional microporous fluorogallophosphate, named Mu-2,was synthesized from a fluoride-containing aqueous medium in thepresence of 4-amino-2,2,6,6-tetramethylpiperidine as organictemplate. The new material was characterized by microprobe analysis,thermal analysis, X-ray diffraction and solid state NMR spectroscopy.Its structure was determined from X-ray powder as well as singlecrystal data. The structure of Mu-2[Ga32P32O120(OH)16F8(C9H20N2H)4(C9H20N2H2)2 · 12H2O,M r = 6687.0, cubic, space group I23 (no. 197), a = 16.3782(2) Å, V = 4393.38(1) Å3, Z = 1, R F = 7.7% R wp = 10.7%] consists of acubic arrangement of double-four-ring units (D4R) hosting F− anionswhich are interconnected to form a three dimensional but interruptedframework. This arrangement generates a three-dimensional pore systemof eight-membered ring channels. Besides the D4R units, two othertypes of cages are present in the structure occluding the protonatedamine and a (OH)8-(H2O)6-cluster respectively.