EXAFS Study on the Dehydration Process in Mg(OH)₂

Abstract

Extended X-ray absorption fine structure (EXAFS) measurements were carried out to investigate the local structure around the light atom (Mg) in dehydrated Mg(OH)_2−2xO_x. Using the UVSOR facility, the Mg-K edge spectra were carefully observed below and above the critical concentration of MgO, x_c=0.68. The ratio between the first and the second coordination numbers, N₂⁄N₁, increases with the progress of dehydration in the range of x<x_c and becomes nearly constant above x_c, implying that the vacancy enhancement and destruction of Mg layers occur in the dehydration.