Journal article

Publication year: 1992

Pages: 47-52

Journal: Journal of Inorganic and General Chemistry

Volume number: 614

Issue number: 8

ISSN: 0044-2313

DOI Link: https://doi.org/10.1002/zaac.19926140810

Publisher: Wiley

Abstract: 

Well shaped crystals of NiNb2O6 were obtained by CVT. using Cl2 (added as PtCl2) or NH4Cl as transport agents (1020-degrees-C --> 960-degrees-C). As a result of thermodynamic calculations the migration of NiNb2O6 in the temperature gradient in the presence of Cl2 can be expressed by the heterogenous endothermic equilibrium (1). NiNb2O6,s + 4Cl2,g = NiCl2,g + 2NbOCl3,g + 2O2,g (1)

Assuming DELTA(B)H298-degrees(NiNb2O6,s) = -524.4 kcal/mol a satisfying agreement between thermodynamical calculation and experimental results can be reached.

NH4Cl is less suitable as transport agent, because Ni2+ is partly reduced to the metal by NH3. The additionally H2O produced by this reduction leads to a less favourable equilibrium position of (2) and to low deposition rates. NiNb2O6,s + 8HClg = NiCl2,g + 2NbOCl3,g + 4H2Og (2)

Harvard Citation style: ROSS, R. and GRUEHN, R. (1992) CONTRIBUTIONS ON THE THERMAL-BEHAVIOR OF OXONIOBATES OF THE TRANSITION-METALS .5. CHEMICAL VAPOR TRANSPORT OF NINB2O6 WITH CL2 OR NH4CL - EXPERIMENTS AND CALCULATIONS, Zeitschrift für anorganische und allgemeine Chemie = Journal of Inorganic and General Chemistry, 614(8), pp. 47-52. https://doi.org/10.1002/zaac.19926140810

APA Citation style: ROSS, R., & GRUEHN, R. (1992). CONTRIBUTIONS ON THE THERMAL-BEHAVIOR OF OXONIOBATES OF THE TRANSITION-METALS .5. CHEMICAL VAPOR TRANSPORT OF NINB2O6 WITH CL2 OR NH4CL - EXPERIMENTS AND CALCULATIONS. Zeitschrift für anorganische und allgemeine Chemie = Journal of Inorganic and General Chemistry. 614(8), 47-52. https://doi.org/10.1002/zaac.19926140810