Abstract: An electrolytic cell for the production of a nitrogen trifluoride gas by a molten salt electrolysis comprises electrodes, partition plates, bottom surface, liquid surface of an elecrolytic bath and lids, at least some of these members being in a particular distance relationship.

Abstract: An electrolytic cell for the production of a nitrogen trifluoride gas by a molten salt electrolysis comprises electrodes, partition plates, bottom surface, liquid surface of an electrolytic bath and lids, at least some of these members being in a particular distance relationship.

Abstract: This invention relates to a process for obtaining a high purity nitrogen trifluoride gas which is used as a dry etching agent for semiconductors or a cleaning gas for CVD apparatus, etc., particularly to a process for removing oxygen difluoride. This is a process for purifying a nitrogen trifluoride gas by, after removing hydrogen fluoride from a nitrogen trifluoride crude gas, contacting with at least one aqueous solution containing one selected from the group consisting of sodium thiosulfate, hydrogen iodide and sodium sulfide.

Abstract: The present invention has as its technical theme to provide a liquefactive and condensable method that enables the reaction step of forming NF.sub.3 to be operated safely and continuously and purifying method that eliminates O.sub.2, N.sub.2, etc. in NF.sub.3.The present invention is directed to a method wherein liquefaction and condensation of NF.sub.3 is carried out with an additive gas such as He, and Ne introduced in order to prevent H.sub.2 from mixing. The present invention is also directed to a purifying method wherein deeply cooled distillation of liquefied NF.sub.3 is carried out with one or more of He, He, and Ar introduced as a third component gas.According to the present invention, a safe long-term continuous operation has been made possible. Since O.sub.2, N.sub.2, etc. in NF.sub.3 can be eliminated efficiently, highly pure NF.sub.3 can be obtained.

Abstract: The method for preparing a gaseous metallic floride is here disclosed which comprises reacting a metal or its oxide with a fluorine gas or nitrogen trifluoride gas, the aforesaid method being characterized by comprising the steps of mixing the metal or its oxide with a molding auxiliary comprising a solid metallic fluoride which does not react with fluorine and nitrogen trifluoride; molding the resulting mixture under pressure; and contacting the molded pieces with the fluorine gas or nitrogen trifluoride gas, while the molded pieces are heated.

Abstract: There is here disclosed a method for removing nitrous oxide (N.sub.2 O), carbon dioxide (CO.sub.2) and dinitrogen difluoride (N.sub.2 F.sub.2) from a nitrogen trifluoride gas. The present invention is directed to a method for purifying a nitrogen trifluoride gas which comprises the steps of thermally treating, at a temperature of 250.degree. to 700.degree. C., a zeolite selected from the group consisting of analcime, clinoptilolite, mordenite, ferrierite, phillipsite, chabazite, erionite and laumotite; forming a packed bed of the treated zeolite; and passing the nitrogen trifluoride gas containing the gaseous impurities at a temperature of -125.degree. to 50.degree. C. through the filler layer.