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The main structural building blocks that form manganese oxides are MnO6 octahedra; these share corners and edges to construct specific structures, which can either be tunneled or layered. In the layered structures, that is, phyllomanganates, the MnO6 octahedra form sheets, which, in turn, alternate with sheets of metal oxides and H2O. These metal ions can vary (Zn, Co, Ni, Al, Li, ...) and give rise to an entire range of different metal oxides. The characterization of these layered materials is important as they have various economical/industrial applications. Birnessite‐type materials, a specific type of layered manganese oxides, are widely studied for their use as cathode materials in alkali‐ion batteries. Phyllomanganates are also commonly found as constituents in sediments and soils or as coatings on rock surfaces. Their natural occurrence as black colored components have ensured that these minerals were also applied as pigments in archaeological and historical contexts. They are, for example, often found in rock art paintings and on pottery. As the oxides are used in unique archaeological objects, Raman spectroscopy is an evident choice for characterization due to its non‐destructive nature of analysis. In the current study, five mineral samples of (layered) manganese oxides are analyzed with different Raman instrumentations, including mobile systems and a benchtop micro‐Raman setup. The characterization of each selected manganese oxide and their comparison with literature data is discussed for the micro‐Raman instrumentation. In addition, the ability of identifying and characterizing layered manganese oxides and the possible challenges when using mobile instrumentation are discussed as well. [ABSTRACT FROM AUTHOR]

Manganese oxides have attracted the interest of many researchers due to their broad application field. These oxides possess various electrochemical, adsorption and catalysis properties and are as such applied in the industrial context, for example, steel industry, catalysis and removal of toxins in the ground or in waste water. In the archaeometrical field, manganese oxides have been used as pigments on various artefacts such as pottery and rock art paintings. The diversity of manganese oxide applications highlights the need for a well‐defined Raman spectroscopic database with correct characterization of these compounds. However, identification of manganese oxides by Raman spectroscopy is challenging due to the wide variety of manganese oxides, and manganese oxides are weak Raman scatterers and are susceptible under the laser light. As such, characterization by Raman spectroscopy is not straight forward. In this research, we have focussed on seven natural, mineral (tunnel) samples that were identified by micro‐Raman spectroscopy using two different laser wavelengths (785 and 532 nm). The experimental conditions were controlled to not introduce any modifications (degradation and/or phase transition) of the manganese oxide species. Both lasers have proven to be successful and were able to retrieve well‐characterized Raman spectra for each of the manganese oxide phase, which were compared with published literature. [ABSTRACT FROM AUTHOR]

Micro‐Raman spectroscopy was used for the analysis of painted pre‐Islamic ceramics from the Kur River Basin (Fars Province, Southwest Iran). A total of 21 sherds were analysed dating from the Neolithic to the Late Bronze Age and belonging to different ceramic wares and sites. The main focus of this research was to identify the pigments used for the red and black decorations of the different ceramic wares from the Kur River Basin and to elaborate on the manganese identification and their differentiation through Raman spectroscopy. Haematite (α‐Fe2O3) and manganese oxides could be identified as the main compounds for the decoration in the different ceramic wares, except for the Bakun ware in which also carbon black could be determined as a probable pigment for black decoration using micro‐Raman spectroscopy. The identification and discrimination of manganese oxides were a meticulous task due to the sensitivity of these materials to the laser power, which can provoke degradation. Nevertheless, Raman spectroscopy was successfully applied for the identification of spectral patterns of the ceramics and their attribution to several manganese oxides present in the decorative mixtures, such as jacobsite (MnFe2O4), bixbyite (α‐Mn2O3) and hausmannite (Mn3O4). [ABSTRACT FROM AUTHOR]