Preparation and Crystal Structure of Sodium Iron Hydrogen Phosphate, NaFe(HPO4)(H2PO4)2 · H2O

✍ Scribed by N. Anissimova; A. Ilyukhin; N. Chudinova; R. Glaum

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: German
• Weight: 137 KB
• Volume: 624
• Category: Article
• ISSN: 0372-7874
• DOI: 10.1002/(sici)1521-3749(199809)624:9<1509::aid-zaac1509>3.0.co;2-e

✦ Synopsis

Single crystals of sodium iron hydrogen phosphate, NaFe(HPO 4 )(H 2 PO 4 ) 2 ´H2 O, were prepared hydrothermally by heating a mixture of Fe 2 O 3 , H 3 PO 4 and Na 2 CO 3 with a small amount of water. It crystallizes orthorhombic (Pbcn (N°60), Z = 8, a = 872.91( 7), b = 1249.54(8), c = 1894.4(1) pm).

The crystal structure was solved by using 1121 unique reflections I > 2r(I) and refined for a final conventional residual R = 0.039 (188 variables, 25 atoms including hydrogen in the asymmetric unit). The main feature of the crystal structure is a ReO 3 -like network formed by hydrogenphos-phate-, dihydrogenphosphate-groups and FeO 6 octahedra with channels along the [201], [010] and [201] directions. Na + and H 2 O molecules are occupying these channels. Effective Coordination Numbers (ECoN), Mean Fictive Ionic Radii (MEFIR) and the Madelung Part of Lattice Energy (MAPLE) are calculated for the title compound.