The Structure of Na2W2O7·12H2O Synthesized under High Pressure and Temperature

✍ Scribed by Magnus Åsberg Dahlborg; Göran Svensson; Markus Valkeapää

• Publisher: Elsevier Science
• Year: 2002
• Tongue: English
• Weight: 436 KB
• Volume: 167
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.2002.9675

✦ Synopsis

A new compound, Na 2 W 2 O 7 . 1 2 H 2 O, has been found in the Na 2 O-WO 3 -H 2 O system. It is the fourth compound in the Na 2 W 2 O 7 . xH 2 O system and the second phase containing water. The crystals were prepared at a pressure of 1.5 GPa and a temperature of 9001C. Na 2 W 2 O 7 . 1 2 H 2 O crystallizes in the triclinic space group, P % 1; Z=2, with lattice constants of a=8.4902(6) ( A, b=7.6636(6) ( A, c=5.1501(3) ( A, a=91.959(7)1, b=96.521( 8)1 and c=111.678(7)1. The structure is built up from double chains of WO 6 octahedra running along c, interconnected by two-dimensional nets of NaO 6 polyhedra. Sodium coordinates to six oxygens forming both octahedra and trigonal prisms.