Prehnite at the Atomic Scale: Al/Si Ordering, Hydrogen Environment, and High-Pressure Behavior

Simple item page
dc.contributor.authorDetrie, Theresa A.en
dc.contributor.committeechairRoss, Nancy L.en
dc.contributor.committeememberAngel, Ross J.en
dc.contributor.committeememberBallaran, Tiziana Boffaen
dc.contributor.departmentGeosciencesen
dc.date.accessioned2014-03-14T20:47:53Zen
dc.date.adate2008-12-10en
dc.date.available2014-03-14T20:47:53Zen
dc.date.issued2008-11-03en
dc.date.rdate2008-12-10en
dc.date.sdate2008-11-14en
dc.description.abstractThe mineral prehnite, Ca2(Al,Fe,Mn)(AlSi3O10)(OH)2, is a layered structure consisting of double-sheets of (Al,Si)O4 and SiO4 tetrahedra alternating with single sheets of AlO4(OH)2 octahedra. To understand the ordering in the structure and differences between various samples of prehnite, single-crystal X-ray diffraction data at ambient conditions were collected on four single crystals of prehnite from different localities. The positions of the H atoms have been determined for the first time, from a combination of X-ray and neutron diffraction data. The equation of state and high-pressure behavior of prehnite have been investigated using single-crystal X-ray diffraction up to 9.75(3) GPa. A second-order Birch–Murnaghan equation of state fit to the isothermal P-V data to 8.7 GPa yields a bulk modulus, K = 109.29(18) GPa. Structural data collected at high pressures indicate that the structure compresses uniformly. Above 8.7 GPa there is additional softening of the volume and the b-axis related to polyhedral tilting. However, the average structure is maintained across the transition. Ambient and high-pressure Raman and synchrotron infrared spectra were collected from 1 bar to 20 GPa. Raman spectra measured at ambient conditions of four prehnite crystals with different compositions confirmed that there are no structural changes with different compositions. High-pressure results showed the majority of modes shift to higher frequencies (in a smooth, linear fashion) with increasing pressure. The greatest change in the spectra is the softening of the modes in the OH-stretching region above 9 GPa, thought to be related to the polyhedral tilting around the H environment.en
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-11142008-092001en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-11142008-092001/en
dc.identifier.urihttp://hdl.handle.net/10919/35702en
dc.publisherVirginia Techen
dc.relation.haspartETD_t.detrie_MSv6.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectprehniteen
dc.subjecthigh-pressureen
dc.subjectX-ray diffractionen
dc.subjectneutron diffractionen
dc.subjectspectroscopyen
dc.subjecthydrogenen
dc.titlePrehnite at the Atomic Scale: Al/Si Ordering, Hydrogen Environment, and High-Pressure Behavioren
dc.typeThesisen
thesis.degree.disciplineGeosciencesen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

Files

Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
ETD_t.detrie_MSv6.pdf
Size:
1.54 MB
Format:
Adobe Portable Document Format
Download

Collections

Masters Theses