Preparation of lanthanide and actinide compounds by CVD method using volatile beta-diketone chelates

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Volatile metal chelates have been used in a wide of applications as fuel additives and catalysts, as metal vapor sources, and in trace metal analysis.There is growing interest in volatile metal b-diketone chelates as vapor source for chemical vapor deposition(CVD). In this work, we are interested in CVD method using volatile beta-diketone chelates with 2,2,6,6, -tetramethyl-3,5-haptanedione(thd), and developed the new preparation method of the metal oxide, sulfide and fluoride films.(1). Preparation of lanthanide fluoride and chloride films was studied by chemical vapor deposition(CVD) using Ln(thd)_3 (Ln=lanthanide(III) ; thd=2,2,6,6-tetramethyl-3,5-heptanedionato ligand) and Y(thd)_3 with gas mixture systems of CF_2Cl_2 (difluorodichloromethane)/O_2 and CF_2Cl_2/H_2.Two kinds of fluorides, LnOF oxyfluoride and LnF_3 trifluoride were obtained separately along a CVD tube by the reaction of Ln(thd)_3 chelates with CF_2Cl_2/O_2 gas system. The chemical characteristics of the CVD products were considered from the points of thermochemical view.(2). We here describe some characteristics of (2,2,6,6, -retramethyl-3,5-heptanedionato) thallium(I), and preliminary experiments in the CVD between this chelate and some reactant gases. The precipitation was isolated by filtration, allowed to dry, and was purified by sublimation in vacuum. In conclusion, the present Tl(thd) chelate is useful and porential as a thallium vapor source for CVD and gas-phase reaction investigations.