Growth, Morphology, Structure and Properties of Na3BaCl5 2H2O Crystals

✍ Scribed by K. Byrappa; M. A. Khandhaswamy; V. Srinivasan

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 394 KB
• Volume: 34
• Category: Article
• ISSN: 0232-1300
• DOI: 10.1002/(sici)1521-4079(199908)34:7<843::aid-crat843>3.0.co;2-w

✦ Synopsis

Single crystals of Na 3 BaCl 5 .2H 2 O were obtained from saturated aqueous solutions at two different temperatures (27° C and 32° C). The crystal size increases with increasing temperature. The crystals obtained were subjected to a systematic morphological, X-ray and thermal analyses. The study of asgrown crystal morphology and surface morphology of Na 3 BaCl 5 .2H 2 O crystals clearly indicate the requirement of a slow rate of evaporation at temperatures 27 to 28° C, moderate supersaturation in order to obtain high quality single crystals of Na 3 BaCl 5 .2H 2 O . The X-ray diffraction studies give the following cell parameters for the title compound: monoclinic, P2 1 /n, a = 8.5773( 9), b = 9.5502(4), c = 5.2873(3) Å, ß =92.069° , V = 432.8 Å 3 , Z = 2. The study of TGA curves indicate the occurrence of dehydration process at around 200° C and not the decomposition of the compound. Similarly, the low temperature DSC study indicates a thermal anomaly at 267 K, and the high temperature DSC study (323 K to 873 K) indicates the transition from dihydrate to monohydrate and in turn anhydrous state at 454.6 K for Na 3 BaCl 5 .2H 2 O crystals. Thus both the TGA & DSC curves conclude that the Na 3 BaCl 5 .2H 2 O crystals contain two molecules of water of crystallization and its molecular formula is Na 3 BaCl 5 .2H 2 O .