Electronic absorption spectroscopy, chromium

A discussion on the main spectroscopic techniques used in mineralogy and materials science is beyond the scope of this chapter. Several treatises and scientific papers dealing with this topic are already available. On the other hand, a thorough understanding of the local phenomena occurring when chromium is incorporated into the octahedral site of a perovskite structure, and, consequently, the know-how of deriving chromium-oxygen local distances is an essential requirement For this reason, in this section, it will be briefly explained how to obtain local bond distances by means of the electronic absorption spectroscopy (EAS), which is one of the most common and well-documented spectroscopic techniques in mineral sciences. 

Pavlov, R.S., Marza, V.B., and Carda, J.B. (2002) Electronic absorption spectroscopy and colour of chromium-doped solids. 

X-ray powder diffraction patterns were obtained on oriented film specimens [7] (2 to 45° 2 , Philips PW 1120, monochromatized CuKa radiation, continuous peak registration). BET surface area and the pore volume distribution were determined from Nj adsorption-desorption isotherms at 77 K (degassing at 393 K, lO" mbar, 5h Sorptomatic 1900, Carlo Erba Instruments). The IR-spectra were recorded on KBr wafers [4] with a Specord 80M spectrometer. The XPS (X-ray photoelectron spectroscopy) spectra were obtained with VG ESCALAB 200 MKII spectrometer equipped with a twin anode AIKa source (1486 eV). The thermogravimetric (TGA) analyses were carried out with a Setaram TG 85 thermobalance at a heating rate of 6 K min in a helium flow of 30 ml min . The chromium content of the samples was determined by EPMA (JEOL 840 scanning electron microscope) with energy dispersive spectrometer (EDS, Tracer Northern) and by AAS (atomic absorption spectroscopy, Perkin Elmer 3030) analyses. 

Catalano JG, Warner JA, Chen C-C, Yamakawa I, Newville M, Sutton SR, Ainsworth CC, Zachara JM, Traina SJ, Brown GE Jr (2001) Speciation of chromium in Hanford Tank Farm SX-108 and 41-09-39 core samples determined by X-ray absorption spectroscopy. In Groundwatcr/Vadosc Zone Integration Project Report, S-SX FIR Appendix E, Digest of S T Evaluations, p E-145-E-162 Cazaux J (2001) Electron- and X-ray-induced electron emissions from insulators. Polymer International 50 748-755... 

NMR spectroscopy has been used to characterize aluminium chromium mixed oxides.The Mo chemical shifts, electronic absorption bands, and solvent donor numbers have been examined for [Mo2(02CR)4L2] solvent adducts. NMR spectroscopy has been used to confirm the presence of three different types of oxygen atoms in [ (ri -4-MeC6H4Pr )Ru 4Mo40i6]. The NMR spectrum of [HPW9034] is a five line, 1 2 2 2 2, spectrum. has... 

Several techniques are available for determining whether or not toxic metals, such as lead and chromium, exist in paint. Some well-established methods, particularly for lead, are atomic absorption (AA) and inductively coupled plasma atomic emission spectroscopy (ICP or ICP-AES). Energy-dispersive x-ray in conjunction with scanning electron microscopy (EDX-SEM) is a somewhat newer technique. 

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