Abstract Stoichiometric molecular solid-state vibrational ball milling, solvent-free kneading ball milling, and mechanochemical ball milling of varied aldehydes and ketones with unmodified sodium borohydride under temperature control uses all hydrogen atoms of the reducing agent in fast reactions. It provides quantitative yields of thermally stable sodium tetraalkoxyborates. The easily isolated solids are extremely sensitive towards hydrolysis, ...