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The mineral wheatleyite has been synthesised and characterised by Raman spectroscopy complimented with infrared spectroscopy. Two Raman bands at 1434 and 1470 cm −1 are assigned to the n .C -O/ stretching mode and implies two independent oxalate anions. Two intense Raman bands observed at 904 and 860 cm −1 are assigned to the n(C-C) stretching mode and support the concept of two non-equivalent oxalate units in the wheatleyite structure. Two strong bands observed at 565 and 585 cm −1 are assigned to the symmetric CCO in plane bending modes. The Raman band at 387 cm −1 is attributed to the CuO stretching vibration and the bands at 127 and 173 cm −1 to OCuO bending vibrations. A comparison is made with Raman spectra of selected natural oxalate bearing minerals. Oxalates are markers or indicators of environmental events. Oxalates are readily determined by Raman spectroscopy. Thus, deterioration of works of art, biogeochemical cycles, plant metal complexation, the presence of pigments and minerals formed in caves can be analysed.

Abstract:Raman spectroscopy has been used to characterise four natural halotrichites: halotrichite FeSO 4 .Al 2 (SO 4 ) 3 4 . Raman bands at around 474, 460 and 423 cm -1 are attributed to the ν 2 (A g ) SO 4 mode. The band at 618 cm -1 is assigned to the ν 4 (B g ) SO 4 mode. The splitting of the ν 2 , ν 3 and ν 4 modes is attributed to the reduction of symmetry of the SO 4 and it is proposed that the sulphate coordinates to water in the hydrated aluminium in bidentate chelation.Key words: apjohnite, pickingerite, halotrichite, wupatkiite, jarosite, sulphate, Raman spectroscopy Introduction Sulphate efflorescences have been known for some considerable time 1-3 . These often occur in tailings impoundments (see Jambour et al. p322) 4 . The sulphate formation results from the oxidation of pyrite. Halotrichites are formed close to pyrite and are often found with copiapites and related minerals 5 . The minerals are found in efflorescences of geothermal fields 6 . Halotrichite has a formula• Author for correspondence (r.frost@qut.edu.au)

The Cu-ZnO catalyst precursors with variable Cu:Zn ratio, between Zn-rich and Cu-rich compositions have been investigated by a combination of electronic and vibrational spectroscopy. Synthesized catalyst precursors exhibit two d-d transition bands of Cu 2+ ions in a distorted octahedral symmetry, at 7,600 and 12,900 cm -1 (1,315 and 775 nm). The effect of structural cation substitution (Zn 2+ and Cu 2+ ) on band shifts is observed in the spectra of the synthetic catalyst precursors. The observation of two broad features at *7,600 and 12,900 cm -1 (1,315 and 775 nm) is a strong indication for Zn 2+ substitution by Cu 2+ ions. The result of multiple bands in the symmetric stretching and bending regions confirms the reduction of symmetry from D 3h to C 2v /C s for (CO 3 ) 2-ion in aurichalcite. The synthetic aurichalcite may be used as a standard for identification of spectral properties of naturally occurring anhydrous carbonate minerals.

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