Crystal structures and isotope effect on Na5H3(SeO4)4·2H2O and Na5D3(SeO4)4·2D2O crystals

✍ Scribed by T. Fukami; J. Miyazaki; T. Tomimura; R. H. Chen

• Publisher: John Wiley and Sons
• Year: 2010
• Tongue: English
• Weight: 220 KB
• Volume: 45
• Category: Article
• ISSN: 0232-1300
• DOI: 10.1002/crat.201000116

✦ Synopsis

Differential scanning calorimetry (DSC) and X-ray diffraction measurements have been performed on pentasodium trihydrogen tetraselenate dihydrate Na 5 H 3 (SeO 4 ) 4 •2H 2 O and deuterated Na 5 D 3 (SeO 4 ) 4 •2D 2 O crystals. Any distinct anomaly around 428 K in the DSC curves for both crystals is suggested to be caused by a chemical reaction of thermal decomposition with hydrolysis at high temperature. The space group symmetry (triclinic P1) and the structure parameters are determined at room temperature. The hydrogen atom in the centrosymmetric O-H(D)-O hydrogen bond of both crystals is found to be equally distributed at two equivalent sites in the bond. The expansions of two O-H-O hydrogen bonds by the substitution of deuterium are observed to be 0.016(6) and 0.011(4) Å. The geometric isotope effect on hydrogen bonds is confirmed to be existed in Na 5 H 3 (SeO 4 ) 4 •2H 2 O.