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Who determined the exact composition of ammonia in 1785?

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Difference in molecular structure between ammonia/amines and quaternary ammonium ions — ammonia Ammonia and amines have a slightly flattened trigonal pyramidal shape with a lone pair of electrons above the nitrogen. In quaternary ammonium ions, this area is occupied by a fourth substituent.

The French chemist Claude-Louis Berthollet determined the exact composition of ammonia in 1785.1

While Joseph Priestley had first prepared pure ammonia in 1774, it was Berthollet who successfully decomposed the gas into its constituent elements—nitrogen and hydrogen—thereby establishing its chemical makeup.21