The Binding State of Indium in Natural Chalcogenides: In
• • • THE BINDING STATE OF INDIUM IN NATURAL CHALCOGENIDES: IN
A XANES APPROACH THROUGH THE L 3 ABSORPTION EDGE * Laboratório Nacional de Energia e Geologia
Cancún, Mexico Ma Ondina FIGUEIREDO & Teresa PEREIRA da SILVA August 16-20, 2009 CENIMAT/I3N, Mat. Sci. Dpt., Fac. Sci. Techn., New Univ. Lisbon, A Brief Summary of Indium Crystal Chemistry Symposium 20 2829-516 Caparica, and LNEG, Geol. Data Centre, Apt. 7586, Assigned as a native metal associated with lead in Transbaikalia [4], indium 2721-866 Alfragide, Portugal (Z=49) has the electronic structure [Kr] 4d10 5s2 5p1, and frequently assumes the Poster nr. 1 trivalent state, thus suggesting the inertness of 5s2 electron-pair. Like gallium Introduction MAIN CRYSTAL STRUCTURE-TYPES (STP) of NATURAL and unlike tin - other important “High-Tech” elements -, indium seldom forms Indium became one of the most relevant scarce CHALCOGENIDES (Minerals) specific minerals, occurring dispersed within polymetallic sulfide ores (Table 1). Octahedral Sulfides metals used in the last decades to produce new The sulphide roquesite (CuInS2) was the first In-mineral to be described [5], Disulfides |S=S| dimers SULPHO- “high-tech devices” based on innovative nano- followed [6] by indite (Fe In2 S4) and dzhalindite, a tri-hydroxide with In (OH)6 o t
In O 3 757.8 2 3 S Fig. 5 3 742.8 3 760.5 In F3 3 745.5
[Periodic Table from K. KRAUSKOPF (1967) Introduction to Geochemistry]
Pyrite Tetrahedral structures Galena-plus-sulphosalts / Anions (blende, wurtzite & allied) Fig. 6 − In L3-edge XANES spectra: 3 732.1 E (eV) ID 21 (a) model compounds; (b) points in Experimental beamline chalcogenide sample LS5-180.6 [11]
The X-ray absorption spectroscopy experiment at In L3-edge was carried out using the instrumental set-up of ID-21 beamline [10] Results In L3-edge XANES spectra Fig. 7 (fig. 5) at the ESRF (European Synchrotron Radiation Facility). From [13] X-ray absorption spectra reflect the local symmetry Fe S2 A polymetallic chalcogenide ore (In ~ 90ppm) from Lagoa Salgada and chemical bonding of the absorbing element and the ZnS [11] was irradiated, along with metallic indium and model compounds band character of the compound through the position of displaying distinct bonding situations of indium to other ligands the edge jump and the details that follow; the presence of a S2 (oxygen and halides). XANES spectra were collected in fluorescence “white line” indicates unoccupied electronic states [12]. Fe yield mode using a photodiode detector mounted in the horizontal Beyond a white line at 3732.1eV (fig.6a), also displayed
plane perpendicular to the X-ray beam, irradiating directly the rough by InF3 XANES spectrum (fig.6b), the spectra collected from sample fragments with a beam-size of 1x0.3μm2. A fixed-exit Si(111) E (eV) the chalcogenide ore show an extra white-line at 3726.5eV PbS monochromator was used for the energy scans, assuring an energy plus details also observed in the spectra of the metal and 0.4 eV resolution of at the In L3-edge. model compounds In2O3 & InF3. Although the In L3-edge 100 μm Fig. 10 – Crystal structure of trigonal spectra from the oxide (fig.7) was already studied in the Fig. 8 – Photomicrograph of a References In F3 [17], with ideal crystal context of ITO thin-films [13] and the spectra from the o h polished section of ore sample [1] E. FORTUNATO, et al. (2005) Adv. Materials 17, 590-594. chemical formula In [F3] metal was discussed a few years ago [14], further study is In LS5-180.6. A fissure is shown in [2] M.O. FIGUEIREDO et al. (2007) Procd. 9th Biennial SGA Mtg., In3+ cations fill only 1/3 of clearly required to fully interpret the spectra collected from Dublin/Ireland, edt. C. Andrew et al., 1355-1357 (ISBN 0-950989-4-4). black. Grains: dark grey, pyrite the available octahedral sites. natural chalcogenides (fig.6a) which are quite distinct from (FeS ); (ZnS); [3] O.C. GASPAR (1984) Mem.& Notícias, Museu Lab. Miner. Geol., F 2 light grey, sphalerite Univ. Coimbra, 98, 137-150. (in Portuguese). the XANES spectra of synthetic spinel-type In2S3 [15]. white, galena (PbS). [4] V.V.IVANOV (1964) Cf. Handbook of Geochem. (1974) Springer- Verlag, vol. II-4, p. 49-A. c Fig. 9 - Condensed-model standard sheet [16] for [5] P. PICOT & R. PIERROT (1963) Bull. Soc. Fr. Min. Crist. 86, 7-11. t o c/h Final Comments [6] A.D. GENKIN & I.V. MURAVEVA (1963) Cf. Amer. Min. 49, 493. A 2 D [X] = [7] M.O. FIGUEIREDO & M.J. BASTO (1986) Garcia de Orta, ser. Geol., Large circles, closest The closest packing array built up by S anions in most Lisboa / IICT 9, 41-53 (in Portuguese). packing atoms (X); A, chalcogenide minerals present in ore sample LS5-180.6 (fig.8) − [8] H. SCHWARTZ, et al. (1995) Zeit. für Kristallogr. 210, 342-347. tetrahedral (t), and D, chalcopyrite, sphalerite, tetrahedrite-tennantite, galena − is very [9] M. EPPLE, et al. (2000) Zeit. für Kristallogr. 215, 445-453. o octahedral sites (o). th suitable to lodge polymetallic cations by filling closely located [10] J. SUSINI et al. (2000) Proc. 6 Internat. Conf. X-Ray Microscopy, X A t Amer. Inst. Phys. 507, 19-28. Ideal radii: rA=0.225 rX interstitial sites, as illustrated by the condensed model sheet of th [11] D. OLIVEIRA et al. (2009) 10 Biennial SGA Mtg., Australia, August. D rD = 0.414 rX a single anionic layer figuring out the interstices available [12] M. BROWN et al. (1977) Phys. Rev. B 15, 738-744. [t-o] & [t-t] distances between successive layers (fig.9). Considering that InF3 is also [13] V. SUBRAMANIAN, et al. (2004) Solid State Ionics 175, 181-184. are assigned in color. a closest-packed compound, despite hexagonal (fig.10), it is not [14] T.K. SHAM (1985) Phys. Rev. B 31, 1888-1902. to exclude that interactions may occur between neighbor In [15] M. WOMES et al. (2004) Solid State Comm. 131, 257-260. * Work developed within the research project PTDC / CTE-GIN / 67027 / 2006 financed [16] J. LIMA-de-FARIA (1965) Zeit. für Kristallogr. 122, 346-358. cations, thus accounting for singularities of the observed white by the Portuguese Foundation for Science & Technology (FCT/MCTES). The financial [17] R. HOPPE & D. KISSEL (1984) J. Fluorine Chem. 24, 327-340. lines. Further study is in progress to explore this hypothesis. support from EU to perform the experiments at the ESRF is also acknowledged.