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Growth, Morphology, Structure and Properties of Na 3 BaCl 5 2H 2 O Crystals
Author(s) -
Byrappa K.,
Khandhaswamy M. A.,
Srinivasan V.
Publication year - 1999
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/(sici)1521-4079(199908)34:7<843::aid-crat843>3.0.co;2-w
Subject(s) - monoclinic crystal system , crystallography , anhydrous , crystal (programming language) , crystallization , thermal decomposition , morphology (biology) , aqueous solution , chemistry , supersaturation , dehydration , evaporation , crystal structure , materials science , organic chemistry , thermodynamics , biochemistry , physics , biology , computer science , genetics , programming language
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 as‐grown 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, P21/n, a = 8.5773(9), b = 9.5502(4), c = 5.2873(3) A, β =92.069°, V = 432.8 A 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 and 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.