TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Method: The anhydrous liquid ammonia is introduced at a pressure of 5x 105 to 106 (5-10 bar), preferably 7x 105-9x 105 Pa (7-9 bar). The reactor is inerted preferably with nitrogen or argon prior to the introduction of the anhydrous liquid ammonia. The reactor is thermostated at 18-30 degrees C, preferably at 20 degrees C. The isolation of borazane comprises: withdrawing the heavy phase consisting essentially of the amine, removing anhydrous liquid ammonia of the light phase remained in the reactor by evaporation, and dewatering the obtained solid; or removing anhydrous liquid ammonia of the light phase by evaporation, surmounting the heavy phase, and filtering the mixture resulting from the removal. The method comprises recompressing ammonia removed by evaporation and recycling to the reactor. The method comprises, upstream, the synthesis of amine borane complex from diborane and an amine, where major part of the amine is generated in the reactor, and at least the amine present in the heavy phase is recycled for the implementation of the synthesis of amine borane complex. Preferred Components: The amine borane complex is an alkylamine borane complex, and the amine is a tertiary amine. The amine borane complex is N,N,N-triisopropyl borane complex and/or N,N-diisopropyl N-ethylamine borane (preferred). The molar ratio of anhydrous liquid ammonia/amine borane complex is 5-20, preferably 8-12. EXAMPLE - A glass reactor, jacketed with a volume of 300 ml, carrying a pressure of 106 Pa (10 bar), and equipped with a stirrer with magnetic drive, was used. It was previously been rendered inert with nitrogen, and thermostated at 20 degrees C. Then 0.59 mole of ammonia was introduced into the inert and thermostatically controlled reactor. The agitation was then turned on. Then 0.059 mole N,N-diisopropyl N-ethylamine borane (amine-borane complex) was added in less than 30 seconds. The molar ratio of liquid ammonia/amine borane complex was 10. After 15 minutes, stirring was stopped and mixture of two phases comprising a light phase containing essentially the borazane formed in solution of liquid ammonia and a heavy phase containing essentially N,N-diisopropyl N-ethylamine was obtained. Then borazane present in the light phase was isolated by racking, by a sampling nozzle located at the reactor bottom, the heavy phase containing essentially N,N-diisopropyl N-ethylamine and evaporation of liquid ammonia of the light phase by depressurization of the reactor for 15 minutes at 20 degrees C. The recovered solid borazane contained liquid amine. It was first dewatered by filtration under nitrogen at room temperature under a vacuum of 10 mbar and then vacuum dried in an oven at 20 degrees C for 12 hours under a reduced pressure of 10 mbar, to obtain pure borazane with an yield of 93%. The borazane obtained was stored under argon. The recovered ammonia was recompressed and recycled upstream of the synthesis for reaction with amine-borane complex.