CLASSIFICATION AND TOPOLOGY OF HYDROGEN ENVIRONMENTS IN HYDROUS MINERALS

Abstract

The inspiration for my topic was the use of hydrogen as a fuel source. Currently, the use of hydrogen is limited by the need to find a safe storage solution. I wanted to know how Nature stores hydrogen in minerals. The studies in my dissertation examine the nature of materials that contain hydrogen as OH groups through a variety of techniques. First, I examine the 450 known mineral species that contain isolated OH groups and have crystal structure determinations that include the location of the hydrogen atoms. I identify nine unique classes of OH hydrogen environments. The hydrogen environment exemplified by the mineral behoite is of particular interest because of behoite's structural relationship with SiO₂ cristobalite. I conducted two high-pressure studies exploring the similarities and differences in the behaviors of behoite and cristobalite as a function of pressure. In the process of categorizing the OH hydrogen environments in minerals I encountered minerals who's structures needed to be refined. Refinements for two minerals, despujolsite, a member of the fleischerite group of minerals, and kôzulite, an Mn rich amphibole, are presented and discussed. Two manuscripts, one on the new mineral bobdownsite, and the other on the mineral walstromite, are appended to this dissertation to highlight additional original research conducted throughout my graduate career.