Chemial Bond and Stability of Adsorption of [Au(AsS_3)]~(2-)on the Surface of Kaolinite

1　IntroductionKaoliniteisoneofthemostwide spreadphyllosili catesintheearthcrust.Thegoldiscloselyrelatedtoclayinmanysubmicrometergoldminerals .Itisimportanttostudytheinterrelationbetweengoldandclayforunder standingthecloseassociationofgoldandclaymineralsa…

Chemial Bond and Stability of Adsorption of[Au(AsS3)]2- on the Surface of Kaolinite

Density function theory and discrete variation method (DFT-DVM) were used to study the adsorption of Au(AsS 3)] 2- on the surface of kaolinite.The correlation among structure,chemical bond and stability was discussed.Several models were selected with Au(AsS 3)] 2- in different directions and sites.The results show that the models with gold on the edge of kaolinite basal layer contain pincerlike bond among gold and several oxygen atoms and form strong Au-O covalent bond,so these models are more stable than those with gold above or under the layer.The models with gold near to AlO 2(OH) 4] octahedra are more stable than those with gold near to the vacancy without aluminium.These two stable tendencies in kaolinite-Au(AsS 3)] 2- are stronger than that in kaolinite-Au systems.The interaction between Au(AsS 3)] 2- and kaolinite is stronger than that between gold and kaolinite,and this interaction is strong enough to form the surface complexes.