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Samples representing two modifications of halloysites, dehydrated (7 Å) and hydrated (10 Å) forms, respectively, were examined with the aim to select suitable candidates for to be used as carriers of porphyrine photoactive molecules. The samples were analysed by powder X-ray diffraction (pXRD), infrared spectroscopy (FT-IR), and high resolution transmission electron microscopy (HRTEM). Chemical composition was also determined. For the determination of cationic exchange capacity (CEC) the silver thiourea method (AgTU) was used. Silver cations concentrations in the solution before and after the interaction were determined by atomic absorption spectrometry (AAS). By the interaction of two pure hydrated halloysites with porphyrine it was found that porphyrine does not intercalate the interlayer space, but it is adsorbed on the outer surface of halloysite. This interaction changed the colour of clay sample from white to green. The changes were also clearly visible on diffuse reflectance spectra (DRS).

Vivianite (Fe3(PO4)2·8H2O) is a rare blue historical pigment, which can be profitably used in authorship ascription or copy identification. However, its tendency to degrade complicates its proper identification in paint layers. Reference vivianite mineralogical samples were analysed in order to compare and to test the limits of structural analyses on possibly degraded vivianite samples (X‐ray diffraction and vibrational spectroscopies). The same methods, in their μ‐configuration, were tested on micro‐samples of the paintings and their limits evaluated. A sedimentary origin of the pigment has been suggested. Vivianite was detected in various works by Jean George de Hamilton (1672–1737) and in a Late Gothic Transylvanian altarpiece. [ABSTRACT FROM AUTHOR]

Pre-Romanesque murals at Kostoľany pod Tríbečom, Slovakia, have been investigated by portable X-ray fluorescence and by microanalytical methods to identify painting materials (pigments and binders), and to explain the degradation of colours. Today, missing green and blue shades have been reconstructed according to residual concentrations of Cu, which correspond to copper chlorides-products of salt corrosion of the copper carbonates azurite and/or malachite, accelerated by micro-organisms. As confirmed by powder X-ray microdiffraction, original minium (Pb3O4) has been transformed to brown-black plattnerite (PbO2). In increased humidity, even insoluble pigments are washing down from the walls and the intensity of colours further diminishes. [ABSTRACT FROM AUTHOR]

Single-crystals of the layered copper hydroxide acetate Cu2(OH)3(CH3COO)·H2O were synthesized by heating copper acetate solution at 60 °C. The standard synthesis of the title compound based on slow titration of copper acetate solution with NaOH yielded materials with worse morphology and an additional phase present. The obtained products were characterized with powder X-ray diffraction, high temperature powder X-ray diffraction, scanning electron microscopy and infrared spectroscopy. The crystal structure was determined from single-crystal X-ray diffraction data, collected both at 120 K and at 293 K. The title compound crystallizes in the monoclinic botallackite-type layered structure, space group P 21, with the lattice parameters a = 5.5776(3) Å, b = 6.0733(2) Å, c = 18.5134(8) Å, β = 91.802(4)° and a = 5.5875(4)Å, b = 6.0987(4) Å, c = 18.6801(10)Å, β = 91.934(5)° for 120 K and for 293 K, respectively. Acetate groups and water molecules are interlayered between corrugated sheets of edge-sharing CuO6 octahedra exhibiting strong distortion resulted from the Jahn-Teller effect. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

While the most famous historical green earth deposits in Italy and Cyprus were exceptionally rich in celadonite, the deposits near Kadaň, Czech Republic, consisted of thin Fe-rich celadonite impregnations accompanied by interstratified celadonite/smectite. In superimposed tuffs, smectites become prevalent and their colour changes from forest to olive green. Powder X-ray microdiffraction and infrared microspectroscopy permit us to distinguish between green earth minerals in microsamples taken from works of art. The Ti contents and the Fe/Mg ratios help to indicate the presence of Bohemian green earth from Kadaň. We found this material in local 18th-century works of art and also in paintings by Anton Kern (1709-47). [ABSTRACT FROM AUTHOR]

Paintings represent composed materials arranged in successive layers. Development of a suitable method for a depth-profiling analysis is essential for acquiring the information on the stratigraphy as well as on the chemical composition of individual layers, revealing the pigments which had been used. In this study, a depth-resolved analysis of multi-layered model samples of historical easel paintings was performed by means of laser-induced breakdown spectroscopy (LIBS) in combination with non-invasive X-ray fluorescence (XRF). The LIBS analysis was carried out using modified laser ablation system, UP-266 MACRO, equipped with a Czerny-Turner spectrometer. The XRF analysis was performed by handheld spectrometer, Delta Premium. In LIBS experiments, a set of six spots was examined with 5, 10, 15, 20, 25 and 30 pulses respectively, for each of the studied paint samples. Digital and 3D optical microscopy was employed to measure individual layer thickness and to obtain the information on average ablation rates of each sample. The chemical composition of the model samples with each layer partly uncovered was known, and this enabled to directly compare the results obtained by LIBS depth profiling with a fast analysis carried out with the handheld XRF spectrometer. The LIBS depth profiling proved to be a suitable method to distinguish layers of a different material composition and estimate their thickness. The combined use of LIBS and XRF analyses offered essential complementary information on the elemental composition of analysed multi-layered samples. [ABSTRACT FROM AUTHOR]