X-ray study of the nepheline hydrate I structure

✍ Scribed by Staffan Hansen; Lars Fälth

• Publisher: Elsevier Science
• Year: 1982
• Tongue: English
• Weight: 456 KB
• Volume: 2
• Category: Article
• ISSN: 0144-2449
• DOI: 10.1016/s0144-2449(82)80046-8

✦ Synopsis

The structure of nepheline hydrate I, Na3AI3Si3012" 2H20, synthesized hydrothermally at 473 K, has been determined. It is orthorhombic, space group Pna21 with a = 16.426(1 ), b = 15,014(1 ), c = 5.2235(5) ~, Z = 4 and D c = 2.38 g cm -3. The final R = 0.051. The tetrahedral framework consists of a set of parallel two-repeat chains, with single and double chains alternating. The largest channels are bound by eight-ring apertures. Two of the Na ions are coordinated by seven framework O atoms, while the coordination of the third Na ion is three framework and three water 0 atoms. The structure constitutes a link between those of anhydrous tektosilicates and the zeolites. A typical, butterfly-shaped, twinned crystal was examined, and a structural interpretation proposed.