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An understanding of the mineralogy and petrogenesis of rare earth element deposits has significant implications for their economic viability. Lanthanide-bearing compounds are known to produce sharp absorption features in the visible to short-wave infrared region (VIS-SWIR), however, a significant knowledge gap exists between the fields of hyperspectral reflectance spectroscopy and rare earth element mineralogy. Reflectance spectra were collected from four bastnäsite samples, two parisite samples, and one synchysite sample from the visible into the short-wave infrared. These REE fluorocarbonate mineral samples were characterized via scanning electron microscopy and electron probe microanalysis. Sharp absorptions of REE-bearing minerals are mostly the result of 4f-4f intraconfigurational electron transitions and for the light REE-enriched fluorocarbonates, the bulk of the features can be ascribed to Nd 3+ , Pr 3+ , Sm 3+ , and Eu 3+ . The lanthanide-related spectral responses of the REE fluorocarbonates are consistent across the group, supporting the notion that the REE cation site is very similar in each of these minerals. Carbonate-related spectral responses differed between these minerals, supporting the notion that the crystallographic sites for the carbonate radical differ between bastnäsite, synchysite, and parisite. Exploitable spectral differences include a distinct absorption band at 2243 nm that separates bastnäsite from synchysite and parisite. Similarly, for bastnäsite a dominantly Pr 3+ -related absorption band located is at 1968 nm, while in synchysite and parisite it occurs at 1961 nm.

A convenient synthesis of a new dichlorogermaniumbased linker-precursor for solid phase synthesis is described that allows facile introduction of a range of 'spectator' substituents (R) onto germanium. Variation of these R groups allows modulation of the stability of the key germanium-carbon bond between the linker and the aryl library. The tuning process is exemplified by application to the optimisation of a linker for the iterative solid-phase synthesis (SPS) of oligothiophenes.Solid Phase Synthesis (SPS) using parallel or split/mix techniques constitutes an attractive method for the rapid preparation of large libraries of molecules for property screening. 2 Central to the success of the method is the compatibility of the chosen linker with the chemistry required for library construction and diversification. 3 The time required to achieve this compatibility impacts significantly on the overall efficiency of the strategy. Indeed, reservations over potentially long development times probably constitute the most significant impediment to more widespread exploitation of SPS. 4 As no single linker constitutes a panacea for immobilisation via a given functional group, linker selection for SPS usually involves choosing from the growing repertoire of available linkers then experimentation. 5 The process has close analogy with protecting group (PG) selection for solution synthesis except that the choice is currently more limited. Moreover, PG selection is greatly aided by the availability of suites of graded PGs that allow fine-tuning vis-à-vis compatibility for a given application (such as silyl ethers with varying degrees of acid and fluoride stability for alcohol protection e.g. TMS, TES, TBDMS, TIPS, TBDPS etc.). Clearly, the ready availability of similar suites of linkers would be highly advantageous for streamlining the development of SPS programs.We recently described solution phase studies directed towards the development of an iterative SPS of oligothiophenes using a dimethylgermanium-based linker. 6 Our approach exploited the orthogonal susceptibility of a-silyl and a-germyl substituted thiophenes towards nucleophilic ipso-protodemetalation to facilitate 'doublecoupling' after each iteration. This double-coupling tactic was designed to minimise deletion sequences and so aid the preparation of high purity materials with interesting electronic properties. 7 In order to optimise the efficiency of the process and render it sufficiently robust for largescale automated preparations it was desirable to be able to tune the two spectator substituents on the germanium linker (vide infra). The ability to make subtle variations to the ease of electrophilic and nucleophilic ipso-degermylation by such a tuning process was also expected to accelerate the deployment of this strategy for iterative synthesis of other conjugated oligomers incorporating alternative monomers and aid linker selection for other library applications.The preparation of dimethylgermanium linkers 2a-c relied on the 'activation' of trimethylgermanium...