Structure and Vibrational Spectrum ofβ-Cs3(HSO4)2[H2−x(P1−x, Sx)O4] (x∼0.5), a New Superprotonic Conductor, and a Comparison withα-Cs3(HSO4)2(H2PO4)

✍ Scribed by Sossina M. Haile; Pamela M. Calkins; Dane Boysen

• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 774 KB
• Volume: 139
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1998.7861

✦ Synopsis

The structure of the new protonic conductor, -Cs 3 (HSO 4 ) 2 (H 2؊x (P 1؊x , S x )O 4 ) (with a superprotonic transition at 125°C), has been determined by single-crystal X-ray diffraction methods. Structural features of this and the related compound, -Cs 3 (HSO 4 ) 2 (H 2 PO 4 ), have been further examined by Raman and IR spectroscopy. The new compound crystallizes in space group C2/c, contains four formula units in the unit cell, and has an x value (in the stoichiometry) of approximately 0.5. X-ray intensity data, collected at room temperature, yielded lattice parameters a ‫؍‬ 20.04(1), b ‫؍‬ 7.854(5), c ‫؍‬ 8.954(5) A s , and ‫؍‬ 100.11(2)°and a unit cell volume of 1387.5(14) A s 3 , implying a density of 3.304 g/cm 3 . Within the asymmetric unit, 10 nonhydrogen atoms and 3 hydrogen sites were located. Refinement of the X-ray data using anisotropic temperature factors for all 10 of the former yielded residuals wR(F 2 ) ‫؍‬ 0.0952 and R(F) ‫؍‬ 0.0358. The structure contains alternating zig-zig chains of anion tetrahedra and cesium ions, in a manner similar to that found in -Cs 3 (HSO 4 ) 2 (H 2 PO 4 ) and in CsHSO 4 -II. The structure is unique, however, in that P and S occupy the same crystallographic position, and there is, accordingly, a variable H content and a partially occupied hydrogen bond. Broader peaks in the Raman spectrum of -Cs 3 (HSO 4 ) 2 (H 2؊x (P 1؊x S x )O 4 ) support the assumption of greater structural disorder in this compound than in -Cs 3 (HSO 4 ) 2 (H 2 PO 4 ).