Crystal Chemistry of Uranyl Phosphates, Arsenates and Oxysalts of Chromium(V): Implications for Remediation
A total of fifty-six single-crystal structures were studied using diffraction data (collected with a three-circle X-ray diffractometer, Mo radiation, and a charge-coupled-device area detector), in conjunction with the results of other instrumental techniques. Only three of these compounds are from mineral specimens; the rest are synthetic in origin (although many are synthetic equivalents of mineral species), and were grown either by gel-diffusion or by hydrothermal methods. Of the refined structures, twenty-five are uranyl phosphates, twenty-seven are uranyl arsenates, and four are uranyl chromium(V) oxysalts. Four principal structural themes are observed in the uranyl phosphates and uranyl arsenates: 1) structures based on infinite chains of uranyl polyhedra and either phosphate or arsenate tetrahedra; 2) structures based on the sheet found in phosphuranylite; 3) structures based on the sheet found in autunite; and 4) layered and framework structures containing uranyl phosphate or uranyl arsenate sheets whose sheet-anion topology is identical to that found in uranophane. The four uranyl chromium(V) oxysalts are structurally analogous to the uranyl vanadate carnotite.
Uranyl phosphates and their chemically corresponding uranyl arsenates are generally, but not always, isostructural. Similarly, hybrid organic-inorganic compounds, which contain protonated amines rather than simple cations, exhibit structural themes that are analogous with their inorganic counterparts.
History
Date Created
2004-06-30Date Modified
2018-11-01Defense Date
2004-06-21Research Director(s)
Mark McCreadyCommittee Members
Lynda Soderholm Paul McGinn Slavi Sevov Clive R. Neal Peter C. BurnsDegree
- Doctor of Philosophy
Degree Level
- Doctoral Dissertation
Language
- English
Alternate Identifier
etd-06302004-001539Publisher
University of Notre DameProgram Name
- Civil and Environmental Engineering and Earth Sciences