Zersetzungsmechanismus von Mg(OH)2 und Mg(OD)2

Abstract

The conditions have been studied under which the proton of an ionic OH-group can leave the electron cloud of the 0 3-ion to form a HeO molecule with a neighbouring OH-group. The condition of tunnelling is the presence of a free acceptor level of similar height in the neighbouring OH-group. If the two OH-groups are equivalent crystallographically, this condition is not fulfilled since the acceptor level lies higher than the donor level. Coupling with the opposite-phase OH bending vibrations leads to a broadening of the levels and finally to an overlap, which renders the tunnelling possible. The proton transfer starts at the surface as at any given temperature the amplitude of the effective OH bending vibrations is larger at the surface than inside the crystal. Abb. 1 zeigt einen Schnitt durch die Mg(OH)2-Struktur entlang (10i0). Es ist zu erwarten, dab die Tunnelfibertragung zwischen zwei benachbarten OH--Gruppen innerhalb der gleichen (0001)-Ebene erfolgt oder zwischen zwei "auf Lticke" gegentiberstehenden OH--Gruppen zweier benachbarter (0001)

Kinetic parameters

“…As an example, the dehydroxylation of brucite, mineral magnesium hydroxide, has been shown to be a surface reaction, [18][19][20] the dehydroxylation of a few surface layers leading to cracking and exposure of new surface. We are looking at brucite in its relation to other layered minerals; Figure 6 shows an example of the behavior.…”