Report

Linked Reactivity at Mineral-Water Interfaces Through Bulk Crystal Conduction

See allHide authors and affiliations

Science  11 Apr 2008:
Vol. 320, Issue 5873, pp. 218-222
DOI: 10.1126/science.1154833

You are currently viewing the abstract.

View Full Text

Abstract

The semiconducting properties of a wide range of minerals are often ignored in the study of their interfacial geochemical behavior. We show that surface-specific charge density accumulation reactions combined with bulk charge carrier diffusivity create conditions under which interfacial electron transfer reactions at one surface couple with those at another via current flow through the crystal bulk. Specifically, we observed that a chemically induced surface potential gradient across hematite (α-Fe2O3) crystals is sufficiently high and the bulk electrical resistivity sufficiently low that dissolution of edge surfaces is linked to simultaneous growth of the crystallographically distinct (001) basal plane. The apparent importance of bulk crystal conduction is likely to be generalizable to a host of naturally abundant semiconducting minerals playing varied key roles in soils, sediments, and the atmosphere.

View Full Text