A utilização das terras raras (TR) em larga escala teve início com a patente de Welsbach em 1903, que é ainda aplicada na fabricação de pedras de isqueiros. Hoje as TR estão presentes nas mais diferentes áreas, como na produção de superligas, vidros especiais, pigmentos, cerâmicas, imãs permanentes, lasers, eletroeletrônicos, catalisadores, ressonância magnética nuclear, etc., movimentando, na última década, um mercado de US$ 2 bilhões por ano. Devido às suas propriedades muito semelhantes, os elementos das TR são difíceis de serem separados, requerendo, normalmente, processos complexos, o que os torna de elevado preço de comercialização. Elementos como o európio (Eu) e o samário (Sm), cujos teores nos materiais que contém TR são baixos (cerca de 0,05% e 2%, respectivamente, na monazita), são caros e os campos de aplicação destes materiais justificam a busca por outros processos de separação, que sejam no mínimo mais simples e/ou mais eficientes. O estado trivalente é característico para todas as TR, mas alguns elementos podem apresentar outros estados de oxidação, como o Ce, Eu, Sm e Yb. No caso do Eu e do Sm, foco de estudo neste trabalho, o estado divalente é facilmente obtido por redução eletroquímica nos potenciais –0,65V e –1,55V (vs. SCE), respectivamente. Este fato torna possível a separação destes elementos das demais terras raras e entre eles mesmos. Portanto, fazendo uso desta característica, propôs-se um processo de separação individual do Eu e do Sm em meio (NH4)2SO4 por eletro-redução/precipitação, onde o Sm é separado primeiramente como sulfato e o Eu, que permanece em solução, é precipitado após a diminuição da temperatura e do potencial aplicado. O processo desenvolvido a partir de uma solução sintética de Eu e Sm foi aplicado a uma mistura de óxidos de TR semi-pesadas produzida no IPEN-CNEN/SP, obtendo-se a separação do Sm. Este produto foi analisado por espectrofotometria, indicando elevado grau de pureza. / The rare earths (RE) were first used in 1903, when Welsbach developed a lighter that is still used today. Nowadays, the RE are employed in many different fields, as in the production of super-alloys , as catalysts for petroleum industry, in the manufacture of non-ferrous alloys, color television tubes, x-ray screens, special glasses, ceramics, computer industries, nuclear medicine, lasers, pigments, etc., moving, in the last decade , a market of US$ 2 billions per year. Due to their similar properties, the RE elements are very difficult to separate, requiring complex processes, what make the products very expensive. Elements like Eu and Sm, which contents in the minerals are low (0.05% and 2.0%, respectively, in monazite) are extremely expensive, but their field of application justifies the research for looking for other processes, more simple and/or more effective. Trivalent state is a characteristic of all RE, but some of them presents oxidation state +2, like Ce, Eu, Sm and Yb. In the case of Eu and Sm, the focus of the present work, the divalent state is achieved by electro-reduction in the potentials –0.65 and –1.55 (SCE), respectively. This makes possible the separation of these elements from the other rare earths and from each other. Thus, making use of this characteristic, a process for the individual separation of Eu and Sm in (NH4)2SO4 solution by electro-reduction/precipitation is proposed, where Sm is first separated from the solution as sulfate, and Eu, that remains in the solution, is precipitated after the decrease of temperature and potential applied. The process developed from a synthetic Eu and Sm solution was applied to a mixture of semi-heavy RE oxide, produced at IPEN-CNEN/SP, obtaining the separation of Sm. This product was analyzed by spectrophotometry, showing high purity.

本項研究工作主要對五個結構類似的胍基配體， 即 [(2,6-Me₂C₆H₃N)C(NHPri)(NPri)]⁻ (L¹)， [(2,6-Me₂C₆H₃N)C(NHCy)(NCy)]⁻ (L²)， [(2,6-Me₂C₆H₃N)C{N(SiMe₃)Cy}(NCy)]⁻ (L³)， [(2,6-Pri₂C₆H₃N)C{N(SiMe₃)₂}(NC₆H₃Pri₂-2,6)]⁻ (L⁴) 和 [(2,6-Pri₂C₆H₃N)C(NEt₂)(NC₆H₃Pri₂-2,6)]⁻ (L⁵) 與二價鉻以及二價鑭系金屬[Sm(II)、Eu(II) 及 Yb(II)] 的配位化學進行研究，同時，一系列由 L¹ 配體所衍生的三價鑭系金屬配合物亦成功被合成。 / 第一章概括介紹了由胍基配體所構築的金屬配合物的研究背景。 / 第二章敍述了含 L¹ 與 L⁴ 的二價鉻配合物的合成、結構及其化學反應。 通過胍基鉀化合物 [KL¹･0.5PhMe] (1) 與二氯化鉻反應可得到單核二價鉻雙胍基配合物 [Cr(L¹)₂] (3)。 通過胍基鋰化合物 [LiL⁴(Et₂O)] (2) 與二氯化鉻反應，成功製備了單胍基二價鉻配合物 [Cr(L⁴)(μ-Cl)₂Li(THF)(Et₂O)] (4)。 而把二價鉻配合物 4於甲苯溶液中重結晶可得到二聚體的二價鉻配合物 [{Cr(L⁴)(μ-Cl)}₂] (5)。 另外，我們對二價鉻配合物 3 及 4 的反應特性也進行了研究。 [Cr(L¹)₂] (3) 與單質碘、二苯基硫族化合物 PhEEPh (E = S, Se, Te) 以及叠氮金剛烷反應可得相對應的三價鉻混合配體化合物，分別爲 [Cr(L¹)₂I] (6)、[Cr(L¹)₂(EPh)] [E = S (7), Se (8), Te (9)]，及四價鉻配合物 [Cr(L¹)₂{N(1-Ad)}] (10)。 透過單胍基二價鉻配合物 [Cr(L⁴)(μ-Cl)₂Li(THF)(Et₂O)] (4) 與 NaOMe反應可得甲氧基-胍基配合物 [{Cr(L⁴)(μ-OMe)}₂] (11)。 / 第三章主要報導含 L¹， L²， L³ 和 L⁵ 配基的二價鑭系配合物的合成、結構和化學反應特性。 透過 [LnI₂(THF)₂] (Ln = Sm, Eu, Yb) 與胍基鉀鹽反應，我們成功合成一系列二價鑭系絡合物，包括 [{Eu(L¹)(μ-L¹)}₂] (15)， [{Ln(L²)(μ-L²)}₂･nC₆H₁₄] [Ln = Eu, n = 2 (16); Ln = Yb, n = 0 (17)，[Yb(L²)₂(THF)₂] (18)， [Ln(L³)₂(THF)₂･0.25C₆H₁₄] [Ln = Eu (19), Yb (20)]， [{Sm(L³)(μ-I)(THF)}₂] (21) 和 [Sm(L⁵)₂] (22)。 本章亦同時探討二價鑭系配合物15， 18， 20 和 22 作爲還原劑的化學反應特性。 配合物 15 與單質碘反應可得三價銪配合物 [{Eu(L¹)₂(μ-I)}₂] (23)。 配合物 18 與二苯基硫族化合物 PhEEPh (E = S, Se) 反應，可得相對應的三價鐿配合物 [{Yb(L²)₂(μ-EPh)}₂] [E = S (24), Se (25)]。 18 與氯化亞銅反應得到三價鐿配合物 [{Yb(L²)₂(μ-Cl)}₂] (26)。 除此之外，配合物 18 與偶氮苯反應得到雙核配合物 [{Yb(L²)₂}₂(μ-η²:η²-PhNNPh)] (27)， 而 20 與偶氮苯的反應可得單核配合物 [Yb(L³)₂(η²-PhNNPh)･PhMe] (28)。 配合物 22 與二硫化碳的反應得出不對稱偶合配合物 [(L⁵)₂Sm(μ-η³:η²-S₂CSCS)Sm(L⁵)₂] (29)。 / 第四章敍述由胍基配體 L¹ 所衍生的一系列三價鑭系金屬配合物 [Ln(L¹)₃] [Ln = Ce (30), Pr (31), Gd (32), Tb (33), Ho (34), Er (35), Tm (36)] 的合成及其結構。 通過相對應的鑭系金屬三氯化物與 1 反應可得配合物 30-36。 另外， CeCl₃及 LuCl₃與 1 反應亦可合成 [{Ln(L¹)₂(μ-Cl)}₂] [Ln = Ce (37), Lu (38)]。 / 第五章總結了本項研究工作，並對本工作的未來發展作出建議。 / This research work is focused on the coordination chemistry of five closely related guanidinate ligands, namely [(2,6-Me₂C₆H₃N)C(NHPri)(NPri)]⁻ (L¹), [(2,6-Me₂C₆H₃N)C(NHCy)(NCy)]⁻ (L²), [(2,6Me₂C₆H₃N)C{N(SiMe₃)Cy}(NCy)]⁻ (L³), [(2,6Pri₂C₆H₃N)C{N(SiMe₃)₂}(NC₆H₃Pri₂-2,6)]⁻ (L⁴) and [(2,6-Pri₂C₆H₃N)C(NEt₂)(NC₆H₃Pri₂-2,6)]⁻ (L⁵), with divalent chromium and lanthanide metal ions. A series of trivalent lanthanide derivatives of the L¹ ligand were also prepared and structurally characterized in this work. / Chapter 1 gives a brief introduction to the chemistry of metal guanidinate complexes. / Chapter 2 reports on the synthesis, structure and reactivity of chromium(II) complexes derived from the bulky L¹ and L⁴ ligands. Treatment of CrCl₂ with [KL¹･0.5PhMe] (1) afforded the mononuclear Cr(II) bis(guanidinate) complex [Cr(L¹)₂] (3). Reaction of CrCl₂ with [LiL⁴(Et₂O)] (2) resulted in the isolation of ate-complex [Cr(L⁴)(μ-Cl)₂Li(THF)(Et₂O)] (4). Recrystallization of 4 from toluene gave neutral, dimeric [{Cr(L⁴)(μ-Cl)}₂] (5). The reaction chemistry of the Cr(II) complex 3 and 4 was studied. Treatment of 3 with I₂, PhEEPh (E = S, Se, Te), 1-AdN₃ (1-Ad = 1-adamantyl) gave the corresponding mixed-ligand Cr(III) complexes, namely [Cr(L¹)₂I] (6) and [Cr(L¹)₂(EPh)] [E = S (7), Se (8), Te (9)] and Cr(IV) complex [Cr(L¹)₂{N(1-Ad)}] (10). Besides, the reaction of 4 with NaOMe resulted in the isolation of the Cr(II) methoxide-guanidinate complex [{Cr(L⁴)(μ-OMe)}₂] (11). / Chapter 3 deals with the synthesis, structure and reactivity of lanthanide(II) complexes supported by the L¹, L², L³ and L⁵ ligands. Lanthanide(II) guanidinate complexes were prepared by the reactions of an appropriate lanthanide diiodide with the corresponding potassium guanidinate complexes [KL¹･0.5PhMe] (1), [KL²(THF)₀.₅]n (12), KL³ (13) and [KL⁵(THF)₂] (14). Reaction of EuI₂(THF)₂ with 1 gave the homoleptic complex [{Eu(L¹)(μ-L¹)}₂] (15). Metathesis reactions of LnI₂(THF)₂ (Ln = Yb, Eu) with 12 and 13 led to the isolation of [{Ln(L²)(μ-L²)}₂･nC₆H₁₄] [Ln = Eu, n = 2 (16); Ln = Yb, n = 0 (17)], [Yb(L²)₂(THF)₂] (18) and [Ln(L³)₂(THF)₂･0.25C₆H₁₄] [Ln = Eu (19), Yb (20)]. Direct reaction of SmI₂(THF)₂ with 13 yielded the iodide bridged Sm(II) complex [{Sm(L³)(μ-I)(THF)}₂] (21), whilst reaction of SmI₂(THF)₂ with 14 gave homoleptic [Sm(L⁵)₂] (22). The reaction chemistry of 15, 18, 20 and 22 as reducing agents was examined. Oxidation of 15 with I₂ afforded the Eu(III) complex [{Eu(L¹)₂(μ-I)}₂] (23). Reactions of 18 with PhEEPh (E = S, Se) gave the corresponding Yb(III) chalcogenide complexes [{Yb(L²)₂(μ-EPh)}₂] [E = S (24), Se (25)], whilst treatment of 18 with CuCl led to the isolation of [{Yb(L²)₂(μ-Cl)}₂] (26). Besides, addition of complex 18 to PhNNPh yielded binuclear [{Yb(L²)₂}₂(μ-η²:η²-PhNNPh)] (27), whereas treatment of 20 with PhNNPh resulted in the isolation of mononuclear [Yb(L³)₂(η²-PhNNPh)･PhMe] (28). Addition of CS₂ to 22 gave the unsymmetrical coupling product [(L⁵)₂Sm(μ-η³:η²S₂CSCS)Sm(L⁵)₂] (29). / Chapter 4 describes the preparation and structural characterization of lanthanide(III) complexes derived from L¹. A series of homoleptic lanthanide(III) tris(guanidinate) complexes [Ln(L¹)₃] [Ln = Ce (30), Pr (31), Gd (32), Tb (33), Ho (34), Er (35), Tm (36)] were prepared by the reactions of an appropriate LnCl₃ with three molar equivalents of 1. Treatment of CeCl₃ and LuCl₃ with two equivalents of 1 gave the corresponding chloride bridged guanidinate complexes [{Ln(L¹)₂(μ-Cl)}₂] [Ln = Ce (37), Lu (38)]. / Chapter 5 summarizes the findings of this study. A short description on the future prospect of this work will also be given. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Au, Chi Wai. / Thesis (Ph.D.) Chinese University of Hong Kong, 2014. / Includes bibliographical references. / Abstracts also in Chinese.

Neste trabalho foram preparadas as amostras Al2O3:TR3+ (TR3+=Eu, Gd) pelos métodos cerâmico, combustão e Pechini, calcinadas de 400 - 1400 ºC. Os difratogramas de raios X sugerem que as amostras calcinadas em menores temperaturas apresentam-se como sistemas amorfos, que com a elevação da temperatura de calcinação transformam-se na fase cúbica das aluminas ativadas (γ-Al2O3). A partir de 1200 ºC forma-se a fase hexagonal de α-Al2O3, altamente cristalina e termoestável. O tamanho dos cristalitos foi determinado pelo método de Scherrer a partir dos respectivos difratogramas. Em geral, os espectros no infravermelho de Al2O3:Eu3+ apresentaram estiramentos relativos aos grupos tetraédricos [AlO4] condensados e/ou isolados indicando a presença de fase γ-alumina. Foi também observada a existência de bandas em regiões de menores energias atribuídas às freqüências de estiramento de grupos octaédricos [AlO6] relativas à fase α-alumina (coríndon). A Microscopia Eletrônica de Varredura (MEV) indicou que as partículas obtidas pelo método cerâmico apresentam menor tamanho e uma morfologia mais uniforme comparados com aquelas obtidas pelos métodos de combustão e Pechini. Os espectros de emissão (λ exc. = 320 nm) do sistema Al2O3:Gd3+ não apresentam as bandas finas oriundas dos íons Cr3+ observadas nos espectros da alumina não dopada, indicando que íon Gd3+ suprime a luminescência destes íons. Os espectros de excitação das amostras Al2O3:Eu3+ preparadas pelo três métodos apresentam uma banda larga atribuída aos defeitos da matriz Al2O3 e à banda LMCT do O→Eu3+, enquanto que as bandas finas são atribuídas às transições 7F0#&8594;5DJ, 5HJ e 5LJ oriundas do íon Eu3+. Os espectros de emissão dos sistemas Al2O3:Eu3+ (1%), obtidos pelos métodos de combustão, cerâmico e Pechini, e calcinados de 400 - 1100 ºC (λexc. = 394 nm) apresentam bandas alargadas atribuídas às transições 5D0→7FJ do íon Eu3+, sugerindo a ocupação de diferentes sítios de simetria neste sistema evidenciado através do alargamento inomogêneo das bandas atribuídas às transições 4f-4f do íon terra rara. A presença da inomogeneidade das transições eletrônicas 5D0→7FJ para Al2O3:Eu3+ (1%) calcinada de 400 a 1000 ºC sugere que este sistema apresenta predominância da fase gama (γ-Al2O3:Eu3+). A conversão da γ-Al2O3 (fase metaestável) em α-Al2O3 (fase estável - coríndon) promove alterações significativas nos espectros de emissão (λexc. = 394 nm). As amostras calcinadas de 1100 a 1400 ºC exibem um pico fino de alta intensidade (695 nm) atribuídas à linha R do íon Cr3+. A curva de decaimento luminescente do nível emissor 5D0 apresentou um comportamento bi-exponencial indicando que o íon Eu3+ encontra-se em um ambiente químico com diferentes sítios de simetria. O sistema Al2O3:Eu3+ preparado pelo método de combustão (400 - 1100 ºC) apresenta um aumento nos valores dos parâmetros de intensidades Ω2 com o aumento da temperatura de calcinação promovendo uma elevação do caráter covalente da interação metal-doador. Os valores da eficiência quântica de emissão (η) dos sistemas Al2O3:Eu3+ apresentam-se maiores comparados com outros sistemas vítreos. Observa-se que as coordenadas CIE dos compostos Al2O3:Eu3+ localizam-se próximas ao vértice correspondente à cor vermelha sugerindo uma grande contribuição desta cor. / In this work, Al2O3:TR3+ (TR3+=Eu, Gd) samples were prepared by ceramic, combustion and Pechini methods annealed at the temperature range of 400 - 1400 ºC. X-Ray diffraction -XRD patterns suggest that samples heated at lower temperatures are amorphous systems, but when the temperature increases, a change in the cubic phase of activated alumina (γ-Al2O3) is observed. The α-Al2O3 phase showed high crystallinity and thermostability annealed at 1200 ºC. Crystallite size was determined by Scherrer\'s method using XRDs. In general, infrared spectra of Al2O3:Eu3+ show stretching frequencies related to condensed and/or isolated tetrahedral groups [AlO4] indicating the presence of γ-alumina phase. It was observed the existence of bands in lower energies attributed to stretching frequencies of octahedral groups [AlO6] from α-alumina phase (corundum). The scanning electron microscopy (SEM) suggests that particles obtained by ceramic method show the smallest size and the most uniform morphology compared to those prepared by combustion and Pechini methods. Emission spectra (λ exc. = 320 nm) of AlAl2O3:Gd3+ system present no narrow bands arising from Cr3+ ions observed in the spectra of non-doped alumina indicating luminescence quenching by Gd3+ ion. Excitation spectra of Al2O3:Eu3+ samples prepared by three methods present a broad band attributed to defects of Al2O3 matrice and to LMCT state of O→Eu3+, on the other hand, the narrow bands are assigned to 7F0→5DJ, 5HJ and 5LJ transitions arising from Eu3+ ion. Emission spectra of Al2O3:Eu3+ (1%) system prepared by combustion, ceramic and Pechini methods, annealed from 400 to 1100 ºC (λexc. = 394 nm) show broad bands for 5D0→7FJ transitions of Eu3+ ion suggesting that this ion is in different symmetry sites indicated by inhomogeneous line broadening of bands attributed to 4f-4f transition from rare earth ion. The presence of inhomogeneity of 5D0→7FJ transitions for Al2O3:Eu3+ (1%) annealed from 400 to 1000 ºC suggests that this system presents predominantly the γ-alumina phase. The conversion of γ-Al2O3 (metastable phase) to α-Al2O3 (stable phase - corundum) changes significantly their emission spectra (λexc. = 394 nm). The samples annealed from 1100 to 1400 ºC, exhibited a high intensity narrow peak around 695 nm assigned to R lines of Cr3+ ion. Luminescence decay curves of 5D0 emitter level have a bi-exponential behavior indicating that Eu3+ ion is found in a chemical environment with different symmetry sites. The Al2O3:Eu3+ system prepared by combustion method at 400 -1100 ºC presents an increase in the Ω2 intensity parameter values with the increase of annealing temperatures enhancing the covalent character of metal-donator interaction. The values of emission quantum efficiencies (η) of Al2O3:Eu3+ are higher than those for vitreous systems. CIE coordinates of Al2O3:Eu3+ are located near the corner corresponding to monochromatic red color.

O interesse em utilizar terras raras para investigar propriedades e funções de sistemas bioquímicos tanto quanto de determinar substâncias biológicas tem crescido em diferentes áreas, incluindo biomarcadores em imunologia (fluoroimunoensaios). Atualmente, o uso de terras raras no diagnóstico de diversas doenças tem se tornado muito importante com o desenvolvimento de kits de diagnóstico. Como característica principal, as terras raras podem apresentar longo tempo de vida, fotoestabilidade e bandas de emissão finas e bem definidas na região do visível, demonstrando vantagens únicas quando comparadas a outras espécies luminescentes. O presente trabalho teve como objetivo sintetizar molibdatos de terras raras pelo método de coprecipitação, assim como caracterizá-los através de técnicas como: difração de raios X, espectroscopia do infravermelho, análise termogravimétrica, microscopia eletrônica de varredura, microscopia eletrônica de transmissão e estudos de luminescência. Nesse trabalho foram desenvolvidos três diferentes estudos de síntese: a influência da variação da velocidade do dispersor no momento da precipitação; a influência do tratamento térmico na estrutura, morfologia e propriedades luminescentes; e a influência da concentração do íon dopante nas propriedades estruturais e espectroscópicas. Outro passo importante desse trabalho foi o de aminofuncionalizar as nanopartículas utilizando um organosilano (APTES) para recobrir e estabelecer pontos para que essas partículas pudessem se ligar a espécies biológicas. Foi comprovado pelos resultados das caracterizações que esse processo foi eficiente e a incorporação da sílica foi bem sucedida. O Antígeno Específico da Próstata (PSA) foi então ligado às nanopartículas funcionalizadas para possibilitar o diagnóstico de câncer de próstata através de fluoroimunoensaios e dessa forma, níveis de detecção foram estabelecidos. / The interest in using rare earths to investigate the properties and functions of biochemical systems as well as to determinate biological substances has increased in several fields, including biomarkers in immunology (fluoroimmunoassays). Nowadays the use of lanthanides in the diagnosis of various diseases have become more important through the development of commercial diagnostic kits. As main feature, these rare earths can show a long lifetime, photostability and emission bands of atomic like behavior and well defined, in the visible region, demonstrating unique advantages when compared to other luminescent species. The present work had as its goal to synthesize rare earth molybdates by the co-precipitation method as well as to characterize these materials by X-ray diffraction, near infrared spectroscopy, thermogravimetric analysis, scanning electronic microscopy, transmission electronic microscopy and luminescent studies. In this work, three different studied were developed: the influence of the vortex speed variation during co-precipitation in the structure of the final product, morphology and luminescence properties; the influence of the annealing temperature also in the structure, morphology and luminescence properties; and the influence of concentration of the doping in the luminescence properties. Another important step of this work was the functionalization of nanoparticles using an organosilane (APTES) to coat and establish points for binding the particles to biological species. It was proved that this process was very efficient by the characterization results and the silica incorporation was well succeeded. Specific prostatic cancer (PSA) was then linked to the functionalized nanoparticles to diagnostic prostatic cancer by fluoroimmunoassay and levels for detection were established.

One of the largest environmental liabilities facing the Canadian and international mining industry includes the effects of acidic drainage to water resources. This thesis sought to determine biogeochemical mechanisms of rare earth element and yttrium (REY) enrichment in mine drainage, linkages between REYs and microbial populations, and whether REYs were present in water or biofilm at mineable quantities or toxic levels. Water and co-occurring biofilm samples were collected from North and South American mining and control sites, and a passive water treatment system in Pennsylvania. REY concentrations within mineralized biofilm were observed to occur at borderline mineable quantities within biofilm in coal mine drainage (1,000 mg/kg dry weight total REYs), where REYs were bound predominately to particulate organic matter, manganese and iron, limiting their bioavailability. Within the passive treatment system, REYs showed the greatest maximum water-biofilm partitioning coefficients after Al and Fe, and a strong inverse relationship with aqueous REY concentration. Photosynthetic eukaryotes were observed to occur within biofilms that contained an abundance of neutrophilic iron oxidizing bacteria.

Rare earth elements (REE) are an increasingly important group of metals due to their role in the development of modern technologies. Despite being abundant within the Earth’s crust recoverable ores are uncommon, and their mineralization isn’t as well understood as other abundant ore types. In this work, the mineralization of REE occurring in outcrop samples at Hicks Dome, a cryptoexplosive feature that resides in the Wauboukigou Alnöite Province in southeastern Illinois, was studied to determine the mode of mineralization and the origin of the REE. Xenotime-(Y) was identified with a scanning electron microscope in an intrusive breccia and emplaced during or shortly after the uplift which created the oval doming of the Paleozoic section. Whole rock REE concentrations from ultramafic dikes at Hicks Dome closely match global averages of lamprophyres and carbonatites, with a steep La to Lu slope, and enrichment of light rare earth elements. Hicks Dome has unique characteristics relative to the other intrusions in the Province, such as elevated REE, Th, and doming. These traits indicate that the dome was more closely related to an intrusive body at depth that sourced heat, volatile gases, and a suite of rare elements. Based on these data, the REE mineralization and thorium associated with the siliceous breccia is directly related to the alkaline ultramafic intrusion at Hicks Dome. The volatile rich, hot fluids emanating from the ultramafic magma supplied REE and thorium were mixed with the regional fluids responsible for the IKFD.

This work describes detailed convergent beam electron diffraction (CBED) studies of GdAlO3 and LaAlO3 perovskites. CBED patterns tilted away from major zone axes have been found to have high sensitivity to the presence of mirror or glide mirror symmetry. Such patterns confirm to high accuracy that the space group of GdAlO3 is orthorhombic, Pnma. Tilted patterns from this well characterised structure also serve as benchmarks against which similar patterns may be compared. In the case of LaAlO3, tilted patterns enable the space group to be confirmed as rhombohedral R3c, previously claimed to be cubic (Fm3c) by CBED. Furthermore, no evidence for the low symmetry (I2/a or F1) phases proposed for LaAlO3 has been observed. The LaAlO3 study also gives a careful assessment of the influence of tilted specimen surfaces on the CBED data. Within the qualitative scope of these experiments, no symmetry degrading effects could be observed. Some preliminary Quantitative CBED (QCBED) data from LaAlO3 is also presented. This shows it will be possible to make a detailed study of the bonding charge density (Δρ) in this material when combined with X-ray diffraction data. Also included is a brief CBED study of LaFeO3, a material that is isostructural with GdAlO3. Although this is restricted to exact zone axis patterns, it is noted that tilted patterns have significant potential to improve the quality of the symmetry determination.

Bibliography: leaves 132-147 / ix, 147 leaves : ill ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Physical and Inorganic Chemistry, 1987

Thesis (M.S.)--West Virginia University, 2007. / Title from document title page. Document formatted into pages; contains xiii, 119 p. : ill. (some col.), col. maps. Includes abstract. Includes bibliographical references (p. 105-110).

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2007. / Title from title screen (site viewed Dec. 4, 2007). PDF text: xviii, 149 p. : ill. ; 7 Mb. UMI publication number: AAT 3271931. Includes bibliographical references. Also available in microfilm and microfiche formats.