Preparation and Crystal Structures of Mg(NH3)2Cl2, Mg(NH3)2Br2, and Mg(NH3)2I2

✍ Scribed by A. Leineweber; M.W. Friedriszik; H. Jacobs

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 246 KB
• Volume: 147
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1999.8238

✦ Synopsis

IN MEMORIAM JEAN ROUXEL

Diammine magnesium halides Mg(NH 3 ) 2 X 2 with X ‫؍‬ Cl, Br, I have been prepared from magnesium metal and the corresponding ammonium halide in steel autoclaves at 3503C. Mg(NH 3 ) 2 Cl 2 crystallizes in the Cd (NH 3 ) 2 Cl 2 -structure type: Rietveld X-ray analysis, Cmmm, Z ‫؍‬ 2; a ‫؍‬ 8.1810( 2

The bromide and the iodide are isotypic and crystallize in a new structure type: single crystal X-ray analysis, Pbam, Z‫;2؍‬ Mg(NH 3 ) 2 Br 2 : a‫)2(449.5؍‬ A s , b‫)3(678.11؍‬ A s , c‫)1(389.3؍‬ A s , R 1 (F) ‫؍‬ 0 . 045; Mg(NH 3 ) 2 I 2 : a ‫؍‬ 6.285(1) A s , b‫955.21؍‬ (3) A s , c‫)1(203.4؍‬ A s , R 1 (F)‫.080.0؍‬ Both structure types contain chains of edge-sharing octahedra [MgX 4/2 (NH 3 ) 2 ] running along c. These are arranged in di4erent ways relative to one another in the two structure types.