Rehbinder's predictions and advances in mechanochemistry

The results of studying the effect of mechanical action on reactivities of mixtures of powdered monoatomic crystals have been analyzed. The following idea has been discussed: when the dose of mechanical energy absorbed is commensurable with crystal energy, a dynamic equilibrium between disordering and spontaneous regeneration of crystalline structure is established. Under these conditions, amorphous and nanocrystalline structures are formed in individual substances and in their mixtures deformational mixing occurs and metastable products of synthesis are produced. The energy consumption in the syntheses amounts to hundreds of KJ mol(-1) to tens of MJ mol(-1). Both chemical and mechanical factors determine the energy input and the synthesis kinetics in mixtures of solids. The Rehbinder effect and the energy released significantly decrease the energy expenditure. Mechanical properties of components of a mixture manifest themselves in dissolution of a hard component in a soft one and in mutual dissolution of components similar in the properties. (C) 1999 Elsevier Science B.V. All rights reserved.