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Following our previous studies aimed at the valorization of cellulose waste and glycerol, biobased polyols-polyesters were synthesized using both a "green approach" and a novel heterogeneous catalyst based on scandium silicate thortveitite. The latter showed an enhanced linear selectivity compared with most of the analogous catalysts reported in recent studies. Polymers obtained were tested in two important reactions with potential industrial applications: as co-monomers for the synthesis of polyurethanes and as binders for 3D printers. The polyols-polyesters were obtained, with the average molecular weight ranging from 440 to 1050 Da. It is worth noting that the typical polyol polyester used in coatings is branched and has an average molecular weight of 2000–4000 Da. [ABSTRACT FROM AUTHOR]

The present work is part of a systematic mineralogical and petrographic characterization of mica-bearing xenoliths from Somma-Vesuvius volcano (Roman Magmatic Province, southern Italy). Skarns, composite skarns-marbles and cumulates from Pompeii Plinian eruption (AD 79), and skarns and syenite from Avellino eruption (3945 ± 10 cal yr BP) were investigated to define the crystal chemistry of the Somma-Vesuvius trioctahedral micas and to draw inferences on petrogenetic processes to which they were subjected. Xenoliths were characterized by means of polarized optical microscopy, scanning electron microscopy (SEM-EDS), X-ray powder diffraction (XRPD), and bulk-rock geochemical analyses. Mica crystals were studied using electron microprobe analysis (EMPA) and single-crystal X-ray diffraction (SCXRD). Micas from skarns are variably associated with Mg ± Ca silicates (clinopyroxene, vesuvianite, humite, clinohumite, chondrodite, forsterite, and garnet), other sporadic silicates (anorthite, sodalite, titanite, and britholite), apatite, calcite, various types of oxides, as well as rare sulfides and halides. In composite skarn-marble rocks, the mineral assemblages show some differences compared to skarns, as a lack of clinopyroxene and the presence of dolomite. Cumulate samples consist of mica and clinopyroxene, whereas syenite is mainly composed of mica, K-feldspar, feldspathoids, and clinopyroxene. Together with mica, apatite occurs in all the lithotypes. Trace element arrays are scattered for skarn and composite skarn-marble samples. The REE patterns have a general enrichment in light (La, Ce, Pr, Nd) and medium (Sm, Eu, Gd, Tb, Dy) rare earth elements, in some cases with slight positive Gd anomaly. Cumulate samples generally have low amounts of Ba, Sr, Zr, and Th, while syenite exhibits low concentrations of trace elements, except for Rb, Cs, and Tl. Mica crystals occurring in the studied xenoliths are phlogopite with different Al and Mg contents at the octahedral site, a negligible tetraferriphlogopite component and variable dehydrogenation degree. All samples belong to the 1M polytype (C2/m and C2 space group) and have a wide range of unit-cell parameters, especially of the c axis [5.3055(1) ≤ a ≤ 5.3218(1) Å, 9.1893(1) ≤ b ≤ 9.2188(4) Å, 10.1803(2) ≤ c ≤ 10.2951(2) Å]. The shortest c-cell parameter pertains to de-hydrogenated phlogopite from Avellino skarn, whereas OH-rich phlogopite from Pompeii composite skarns-marbles has a c-cell parameter that approximates that of the end-member phlogopite. Overall, it is observed that the crystal chemistry of the micas studied here extends the known range of the other Vesuvian micas from the literature. The Ti-depletion and the wide degree of dehydrogenation of phlogopites from skarns and composite skarns-marbles suggest that the studied samples originated under variable pressure conditions. In addition, the presence of humite in the mineral assemblage seems to indicate the occurrence of devolatilization reactions. The scarce mica occurrence in cumulate and mainly in syenite, instead, may depend on pressure conditions in the magma storage system exceeding the mica stability. [ABSTRACT FROM AUTHOR]

The synthesis and crystallographic analysis of the title compound, C9H9N3O2S, are reported. The compound crystallizes in the monoclinic space group P21/c, revealing characteristic bond lengths and angles typical of thiosemicarbazone groups. The supramolecular organization primarily arises from hydrogen bonding and p-p stacking interactions, leading to distinctive dimeric formations. [ABSTRACT FROM AUTHOR]

The controlled supply of bioactive molecules is a subject of debate in animal nutrition. The release of bioactive molecules in the target organ, in this case the intestine, results in improved feed, as well as having a lower environmental impact. However, the degradation of bioactive molecules' in transit in the gastrointestinal passage is still an unresolved issue. This paper discusses the feasibility of a simple and cost-effective procedure to bypass the degradation problem. A solid/liquid adsorption procedure was applied, and the operating parameters (pH, reaction time, and LY initial concentration) were studied. Lysozyme is used in this work as a representative bioactive molecule, while Adsorbo®, a commercial mixture of clay minerals and zeolites which meets current feed regulations, is used as the carrier. A maximum LY loading of 32 mgLY/gAD (LY(32)-AD) was obtained, with fixing pH in the range 7.5–8, initial LY content at 37.5 mgLY/gAD, and reaction time at 30 min. A full characterisation of the hybrid organoclay highlighted that LY molecules were homogeneously spread on the carrier's surface, where the LY–carrier interaction was mainly due to charge interaction. Preliminary release tests performed on the LY(32)-AD synthesised sample showed a higher releasing capacity, raising the pH from 3 to 7. In addition, a preliminary Trolox equivalent antioxidant capacity (TEAC) assay showed an antioxidant capacity for the LY of 1.47 ± 0.18 µmol TroloxEq/g with an inhibition percentage of 33.20 ± 3.94%. [ABSTRACT FROM AUTHOR]

A synthetic approach to bond lysozyme (LY) to commercial natural carriers, namely clay minerals (bentonite, BN; and sepiolite, SP) and commercial zeolite (Phil 75®, PH), already in use in feed formulation, is proposed. The synthetic route, which implies solid–liquid adsorption, is a simple and effective way for preparing hybrid materials characterized by LY loadings up to 37 mgLY/gcarrier. By operating at pH 4.3, initial LY content of 37.5 mgLY/gcarrier, and reaction time of 90 min, hybrid materials with LY loadings of 37, 35, and 12 mgLY/gcarrier for LY-SP, LY-BN, and LY-PH, respectively were obtained. The LY initial concentration and pH, as well as the physico-chemical properties of the carries were found to be the parameters that govern the synthesis of the materials. The driving force for an effective LY adsorption and interaction is the combined Zero Point Charge (ZPC) of the carriers, always negative (in the range between −4 and −170 mV) and the positive ZPC of LY, as well as the carrier morphology, characterized by mesoporosity (pore dimensions in the range of 5–12 nm). However, it is the interaction of charges of opposite sign that mainly affects LY loadings and bond strength. Based on SEM-EDX analysis, LY molecules are quite homogeneously spread onto the carriers' surface. TG-DTG analyses showed that the LY–carrier interaction in the hybrid materials is stronger than that in a simple mechanical mixture of the components. Specifically, in the hybrid materials, the phenomenon at 300 °C, associated to LY decomposition, is broadened and slightly shifted towards higher temperatures (320–350 °C), whereas in a mechanical mixture of the same composition, it occurs at temperatures closer to those of free LY, as if there were no or very weak interactions. At pH 3, a very little LY release, 0.03 and 0.01 mgLY/gcarrier, was found for LY-BN and LY-PH, respectively. The latter became larger at pH 7, 0.06 mgLY/gcarrier for both BN and PH carriers, suggesting that BN and PH are better modulators of LY release. The paper provides insights for the study and the development of new optimized feed formulations for the targeted delivery of natural compounds with antimicrobial activity, alternatives to antibiotics, and vaccinal antigens. [ABSTRACT FROM AUTHOR]

We provide an updated overview of the known mineral deposits from the Sila and Serre Massifs in Calabria, contributing to setting their genesis within a complex geologic history, starting from the late-Carboniferous. We summarize the mineralization reported in the literature, with a critical review of the host tectonic units, by taking into account the upgrades in the knowledge of these areas. We also set them in updated geological maps and in stratigraphic columns, highlighting the crustal levels to which they pertain. Despite the geologic and minerogenetic similarities potentially existing with late- to post-Variscan mineral deposits from other regions (e.g., Sardinia and French Central Massif), the scientific literature on the Calabria mineralization is out-of-date and not exhaustive. Moreover, these ore deposits were likely considered not economically attractive enough to stimulate new scientific studies. However, in our opinion, such studies are needed to resolve the main open questions, which rely on deciphering the origin and age of mineralization. Finally, research for critical elements hosted by the Sila and Serre mineralization (e.g., In, Ge and Ga in sphalerites) is a possible interesting new perspective. [ABSTRACT FROM AUTHOR]

A multi-methodical characterization of a sauconite (Zn-bearing trioctahedral smectite) specimen from the Skorpion ore deposit (Namibia) was performed by combining X‑ray powder diffraction (XRPD), cation exchange capacity (CEC) analysis, differential thermal analysis (DTA), thermogravimetry (TG), Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM-HRTEM-AEM). The X‑ray diffraction pattern exhibits the typical features of turbostratic stacking disorder with symmetrical basal 00l reflections and long-tailed hk bands, as confirmed by TEM observations. Besides sauconite, the sample contains minor amounts of kaolinite, dioctahedral smectite, and quartz. CEC analysis provides a total of Ca (~69%), Mg (~26%), Na (~4%), and K (0.7%) exchangeable cations. Therefore, Zn is located exclusively within the octahedral site of sauconite. TG analysis of the sample yields a total mass loss of about 17%. Three endothermic peaks can be observed in the DTA curve, associated with dehydration and dehydroxylation of the material. An exothermic peak at 820 °C is also present as a consequence of decomposition and recrystallization. The infrared spectrum shows the typical Zn3OH stretching signature at 3648 cm–1, whereas, in the OH/H2O stretching region two bands at 3585 and 3440 cm–1 can be attributed to stretching vibrations of the inner hydration sphere of the interlayer cations and to absorbed H2O stretching vibration, respectively. Diagnostic bands of kaolinite impurity at ~3698 and 3620 cm–1 are also found, whereas 2:1 dioctahedral layer silicates may contribute to the 3585 and 3620 cm–1 bands. Finally, using the one-layer supercell approach implemented in the BGMN software, a satisfactory XRPD profile fitting model for the Skorpion sauconite was obtained. These findings have implications not only for economic geology/recovery of critical metals but also, more generally, in the field of environmental sciences. [ABSTRACT FROM AUTHOR]

The crystal chemistry and thermal behavior of Fe-carpholite from the Pollino Massif have been investigated by a multi-method approach. A combination of optical microscopy, scanning electron microscopy, mRaman spectroscopy, thermal analysis, room-temperature single-crystal X‑ray diffraction, and high-temperature X‑ray powder diffraction was employed. Field and micromorphological observations showed that the studied carpholite occurs in veins embedded in fine-grained matapelites and coexist with quartz, calcite, chlorite, and phengite. In particular, the tiny carpholite crystals are closely associated with quartz, suggesting simultaneous formation. Structure refinements from single-crystal X‑ray diffraction confirm that carpholite crystallizes in the Ccce space group. Anisotropic refinements converged at 2.3 ≤ R (%) ≤ 2.6 and yielded unit-cell parameters a ~13.77 Å, b ~20.16 Å, c ~5.11 Å, and V ~1419 Å3. An XFe [i.e., the molar fraction Fe2+/(Mg+Fe2++Mn)] of ~0.6 was derived from the refined occupancy at the M 1 site and is correlated to structural expansion mainly along the b and a axes and to geometrical distortions of the M 1, M2, and M3 octahedra. mRaman spectrum of unoriented Fe-carpholite crystals exhibits several bands in the 200–1200 cm–1 region, a strong peak at 3630 cm–1 and a weak peak at 3593 cm–1, the latter two of which account for the presence of two independent OH groups, as also revealed by the X‑ray structure refinement. The TG curve indicates a total mass loss of 15.6% in the temperature range 30–1000 °C, and the DTA curve shows a broad endothermic band at ~400 °C, extending up to ~650 °C, and weak exothermic peaks at ~700 and 750 °C. The latter may be ascribed to the breakdown of the Fe-carpholite structure and crystallization of new phases. The in situ high-temperature X‑ray powder diffraction from 30 to 1105 °C revealed no significant changes in XRD patterns from 30 to 355 °C but reflection splittings from 380 °C due to a Fe-oxidation/deprotonation process. The carpholite and deprotonated carpholite phases coexist in the temperature range 380–580 °C, whereas only the deprotonated phase is observed up to 630 °C. Above this temperature, the carpholite structure collapses and the characteristic peaks of spinel and quartz phases are observed. At 1105 °C, spinel, mullite, garnet, cristobalite, and tridymite can be clearly identified. Our results provide insight into the thermal stability of Fe-carpholites and may help understand the thermal evolution of HP/LT metasediments. [ABSTRACT FROM AUTHOR]

The present work reports the crystal-chemical characterization of micas from the Monte Arsiccio and Buca della Vena mines (Apuan Alps, Italy) through electron microprobe analysis, single-crystal X-ray diffraction, and Raman spectroscopy. The sample from the Monte Arsiccio mine can be classified as an intermediate member of the yangzhumingite-fluorophlogopite series, with average crystal-chemical formula (K0.85Na0.01Ba0.09)Σ=0.95(Mg2.11Fe2+0.23Fe3+0.11Cr3+0.01Al0.20Ti0.04☐0.30)Σ=3.00(Si3.20Al0.80)Σ=4.00O10.00F1.90Cl0.02(OH)0.08. Unit-cell parameters are a ~ 5.30, b ~ 9.18, c ~ 10.14 Å, β ~ 100.12°, V ~ 486.22 Å3, corresponding to the 1M polytype. Structure refinements, performed in C2/m space group, converged to R1 = 3.54 and 4.46% and provided Mg plus Fe occupancy in the range 86–94% for the octahedral M1 and M2 sites. Raman spectroscopy shows very weak bands in the OH stretching region at ~ 3690 and 3580 cm−1. The sample from the Buca della Vena mine has been identified as an (OH)-rich fluorophlogopite, with average crystal-chemical formula (K0.84Na0.02Ca0.01)Σ=0.87(Mg2.12Fe2+0.55Fe3+0.10Al0.18☐0.05)Σ=3.00(Si2.99Al1.01)Σ=4.00O10.00F1.02Cl0.09(OH)0.89. Its unit-cell parameters are a ~ 5.33, b ~ 9.22, c ~ 10.23 Å, β ~ 100.09°, V ~ 494.39 Å3. Structure refinements gave good R1 values (3.27 and 4.37%) and revealed octahedral occupancy of 82–84% Mg and 16–18% Fe. Strong Raman signals at ~ 3702 cm−1 and 3595 cm−1 were observed in the OH stretching region. The findings allow to better understand not only the mineralogy of the Apuan Alps but, more generally, the crystal chemical details of intermediate dioctahedral-trioctahedral mica belonging to the yanzhumingite-fluorophlogopite series. [ABSTRACT FROM AUTHOR]

Asymmetric Schiff base manganese(III) complexes involving salen ligands, N,N'‐bis(salicylidene)2,3‐diaminopyridine, N,N'‐bis(3‐methoxysalicylidene)2,3‐diaminopyridine, N,N'‐bis(3,5‐di‐tert‐butylsalicylidene)2,3‐diaminopyridine and N,N'‐bis(3,5‐di‐chloro‐salicylidene)2,3‐diaminopyridine were prepared and their catalytic activity was investigated in the oxidation of some primary and secondary alcohols. During optimization of oxidation reactions, Mn‐4, bearing electron withdrawing N,N'‐Bis(3,5‐di‐chloro‐salicylidene)2,3‐diaminopyridine ligand, showed higher activity than other catalysts tested. The catalytic reactions were carried out in the presence of various oxidants such as oxygen, hydrogen peroxide or tert‐butyl hydroperoxide (TBHP) and additives such as acetic acid and imidazole. The oxidant/additive combination of TBHP and imidazole was shown to be effective for the oxidation process and the degree of their impact on oxidation reaction was found highly dependent on a balanced ratio between them. Mn‐4 was selected as the most effective catalyst under optimized reaction conditions and revealed efficient for the oxidation of secondary alcohols. [ABSTRACT FROM AUTHOR]

The crystal structure of ferrinatrite, Na3[Fe(SO4)3]·3H2O, was refined based on a new single-crystal X-ray diffraction experiment on a sample from the type locality Sierra Gorda, Chile. The data allowed H to be successfully located and the H-bonding system to be defined. Infrared and Raman spectra are presented and discussed for this compound on the basis of the crystal structure. The Oacceptor···H-Odonor bond distances determined from the structure refinement agree well with the geometric correlation obtained from spectroscopic data. The thermal stability and dehydration process of ferrinatrite was investigated by in situ high temperature (HT) synchrotron X-ray powder diffraction, Raman and Fourier transform infrared spectroscopies. [ABSTRACT FROM AUTHOR]

The thermal dehydration process of fibroferrite, FeOH(SO)·5HO, a secondary iron-bearing hydrous sulfate, was investigated by in situ high-temperature synchrotron X-ray powder diffraction (HT-XRPD), in situ high-temperature Fourier transform infrared spectroscopy (HT-FTIR) and thermal analysis (TGA-DTA) combined with evolved gas mass spectrometry. The data analysis allowed the determination of the stability fields and the reaction paths for this mineral as well as characterization of its high-temperature products. Five main endothermic peaks are observed in the DTA curve collected from room T up to 800 °C. Mass spectrometry of gases evolved during thermogravimetric analysis confirms that the first four mass loss steps are due to water emission, while the fifth is due to a dehydroxylation process; the final step is due to the decomposition of the remaining sulfate ion. The temperature behavior of the different phases occurring during the heating process was analyzed, and the induced structural changes are discussed. In particular, the crystal structure of a new phase, FeOH(SO)·4HO, appearing at about 80 °C due to release of one interstitial HO molecule, was solved by ab initio real-space and reciprocal-space methods. This study contributes to further understanding of the dehydration mechanism and thermal stability of secondary sulfate minerals. [ABSTRACT FROM AUTHOR]

A suite of Ti-bearing garnets from magmatic, carbonatitic, and metamorphic rocks was studied by electron probe microanalysis (EPMA), X-ray powder diffraction (XRPD), single-crystal X-ray diffraction (SCXRD), Mössbauer spectroscopy, and secondary ion mass spectrometry (SIMS) to better characterize their crystal chemistry. The studied garnets show TiO2 varying in the range of 4.9(1) to 17.1(2) wt% and variable Fe3+/ΣFe content. SIMS analyses allowed quantification of light elements yielding H2O in the range 0.091(7)-0.46(4), F in the range 0.004(1)-0.040(4), and Li2O in the range 0.0038(2)-0.014(2) wt%. Mössbauer analysis provided spectra with different complexity, which could be fitted to several components variable from one (YFe3+) to four (YFe2+, ZFe2+, YFe3+, ZFe3+). A good correlation was found between the Fe3+/ΣFe resulting from the Mössbauer analysis and that derived from the Flank method. X-ray powder analysis revealed that the studied samples are a mixture of different garnet phases with very close cubic unit-cell parameters as recently found by other authors. Single-crystal X-ray refinement using anisotropic displacement parameters were performed in the Ia3d space group and converged to 1.65 ≤ R1 ≤ 2.09% and 2.35 ≤ wR2 ≤ 3.02%. Unit-cell parameters vary in the range 12.0641(1) ≤ a ≤ 12.1447(1) Å, reflecting different Ti contents and extent of substitutions at tetrahedral site. The main substitution mechanisms affecting the studied garnets are: YR4+ + ZR3+ ↔ ZSi + YR3+ (schorlomite substitution); YR2+ + ZR4+ ↔ 2YR3+ (morimotoite substitution); YR3+ ↔ YFe3+ (andradite substitution); in the above substitutions YR2+ = Fe2+, Mg2+, Mn2+; ZR4+ = Ti; YR3+ = Fe3+, Al3+, Cr3+; ZR3+ = Fe3+, Al3+. Minor substitutions, such as 2YTi4++ ZFe2+ ↔ 2YFe3+ + ZSi, (SiO4)4- ↔ (O4H4)4-, F- ↔ OH-, and YR4+ + XR+ ↔ YR3+ + XCa2+, with YR4+ = Ti, Zr; YR3+ = Fe3+, Al, Cr3+; XR+ = Na, Li also occur. [ABSTRACT FROM AUTHOR]

The structure, structural disorder and chemistry of miserite from the charoite-bearing rocks of the Murun massif (Russia) and from alkaline-syenite pegmatitic rocks of the Dara-i-Pioz massif (Tajikistan) were investigated employing a combination of electron microprobe, single crystal diffraction and micro-Fourier transform infrared spectroscopy analysis. Chemical analysis of the sample investigated by X-ray diffraction evidenced that Dara-i-Pioz miserite has a greater REE concentration than Murun miserite (~0.22 vs. 0.05 apfu, respectively) and also contains Y (0.14 apfu), which is absent in Murun miserite. The occurrence of a band at about 1,600 cm testified to the presence of HO in miserite at hand. Structural analyses yielded average cell parameters of a = 10.092, b = 16.016, c = 7.356 Å, α = 96.60°, β = 111.27° and γ = 76.34°. Anisotropic structural refinement in space group P $$\bar{1}$$ converged at similar values for the analyzed samples ( R ~3.4, R ~3.8 %). An interesting feature shown by both the miserite specimen is the presence, revealed by difference Fourier analysis, of a disordered part of the structure. This turned out to be due to the flipping of the tetrahedra belonging to the isolated [SiO] diorthogroups, one of the two radicals (the other is [SiO]) characterizing the miserite structure. The sixfold and seven-vertex Ca polyhedra linked to the inverted diorthogroups show variation in coordination number with respect to those of the ordered structure. [ABSTRACT FROM AUTHOR]

Fluorine is an important proxy for magmatic differentiation processes in the shallow parts of volcanic plumbing systems. Fluorphlogopite is one of the more important fluorine carriers in magmatic rocks. In the present study, a full crystal chemical investigation of fluorophlogopite 1M from Piano delle Concazze, Mt. Etna volcano, Italy, is carried out. The fluorophlogopite occurs in a benmoreitic lava from prehistoric volcanic activity at Mt. Etna (post-caldera forming phase of the "Ellittico" eruptive center; ~15 ka BP). It is primarily associated with fluorapatite covered with amorphous SiO2 and crystallized during syn/post-eruption pneumatolytic stages. The mica sample studied here is among the most Fe- and Ti-rich fluorophlogopite found in nature. EPMA data yielded the following mean chemical formula for this mineral (K0.83Na0.13)(Fe0.442+Fe0.093+Mg2.18Al0.05Ti0.23Mn0.01)(Al0.92Si3.08)O10.64 (Cl0.01F1.35). Structure refinements on four fluorophlogopite crystals, performed in space group C2/m, converged at R = 0.03-0.04, with cell parameters in the ranges a = 5.323-5.324, b = 9.219-9.222, c = 10.116-10.119 Å, β = 100.1-100.3°. Major substitutions are OH- ↔ F-,M3+ -oxy (VIM2++OH- ↔ VIM3++O2-) and Ti-oxy substitution: VIM2++2(OH)2+ ↔ VITi4+ +2O2- . The fluorophlogopite from Piano delle Concazze exhibits the shortest c-parameter with respect to other fluorophlogopites found in nature. The short c parameter is essentially due to the absence of the hydroxyl group in favor of F- and especially of O2- and to the thus increased attractive interaction between the interlayer cation and the anion content (F-, O2-) located at the O4 site. A comparison with other natural fluorophlogopites (namely from Biancavilla, Etna and Presidente Olegario, Brazil) show intermediate crystal-chemical features for the Piano delle Concazze fluorophlogopite. Particularly at Etna, differences in the chemical composition of the crystallized fluorophlogopites could be related to the various extent of enrichments by transfer of a gas phase achieved in specific parts of the volcanic plumbing system. [ABSTRACT FROM AUTHOR]

A 3T mica polytype from Kasenyi (southwest Uganda), kamafugite, was studied by electron probe microanalysis (EPMA), single-crystal X-ray diffraction (SCXRD), micro-Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) to characterize its crystal chemistry and the relationships with phlogopites from the same rock but showing different stacking sequence and to get insights into factors affecting polytypism in Ugandan phlogopites. EPMA data gave: SiO2 = 38.7(2), Al2O3 = 13.08(9), MgO = 20.4(2), TiO2 = 4.8(1), MnO = 0.03(3), FeOtot = 5.51(9), Cr2O3 = 0.90(7), NiO = 0.11(5), SrO = 0.03(3), ZnO = 0.04(3), ZrO2 = 0.01(2), K2O = 9.64(5), Na2O = 0.29(1), BaO = 0.15(5), F = 0.13(5), and Cl = 0.01(1) wt%. The analyzed sample may be classified as a Ti-rich phlogopite. X-ray photoelectron spectroscopy provided Fe3+/Fe2+ and O2-/OH equal to ~0.75 and 7.14, respectively, which are in agreement with the results of previous Mössbauer investigation on the BU1 phlogopites from the same rock and with the structural formula of the studied crystal. Infrared spectra showed a shoulder at ~3660 cm-1 in the OH- stretching region (~3740-3600 cm-1), which is assigned to MgMgFe3+-OH--K-O2- local configurations. No evidences of vacancy substitutions were observed. Structure refinement based on single-crystal X-ray diffraction data was performed in space group P3112 using anisotropic displacement parameters and converged to R1 = 4.34 and wR2 = 3.33%. Unit-cell parameters are: a = b = 5.3235(3) and c = 30.188(2) Å. Geometrical and chemical considerations point to a disordered cation distribution over T1 and T2 tetrahedral sites, whereas partial cation ordering characterizes the octahedral sites with high-charge cations preferentially located as expected on M2 and M3. Tetrahedral bond length distortion and angular variance parameters describe more distorted polyhedra in 3T polytype than those found in coexisting 1M and 2M1 polytypes. Finally, the overall crystal-chemical features indicate the occurrence of the following substitution mechanisms in the studied sample: Ti-oxy [VIM2++2(OH) - ↔ VITi4++2(O2-)+H2↑] and Al, Fe3+, Cr-oxy [VIM2++(OH)- ↔ VIM3++O2-+1/2H2)↑]; Al, Fe3+-Tschermak [VIM2++IVSi4+ ↔ VI (Al3+, Fe3+)+IVAl3+]; XIIK++IVAl3+ ↔ IVSi4++XII□; tetraferriphlogopite [IVFe3+↔ IVAl]. [ABSTRACT FROM AUTHOR]

The 2M1-phlogopite from the potassic gabbronorite (Black Hill, Australia) has been studied by electron microprobe and single-crystal X-ray diffraction analyses. The crystal-chemical formula was (K0.95Na0.01)(Al0.15Mg1.27Fe1.162+Fe0.043+Ti0.384+)(Si2.85Al1.15)O10.76F0.11Cl0.03OH1.10. The structural analysis has shown that the crystal has the cell parameters a = 5.352(1), b = 9.268(1), c = 20.168(1) Å, and β = 95.10(1)° and exhibits symmetry lowering from the ideal space group C2/c to C1. An octahedral cation ordering pattern was revealed from the refined site-scattering powers. Specifically, using the scattering species Mg vs. Fe, it was found that the M1 site at z = 0 was occupied principally by Mg (~77%) and subordinately by Fe (~23%), whereas that at z = 0.5 was completely occupied by Fe; the M2 sites at z = 0 displayed ~88% Mg and ~12% Fe, whereas those at z = 0.5 were occupied by ~86% Fe and ~14% Mg. The analysis of geometrical features shows that the Ti uptake in the structure via the Ti-oxy mechanism induces structural distortions of different extents on the z = 0 and z = 0.5 layers, with stronger effects for the layer at z = 0. Minor chemical and structural differences, instead, affect the T sheets at z = 0 and z = 0.5. [ABSTRACT FROM AUTHOR]

In the present work, crystal chemical variations between 1 M and 2 M phlogopites coexisting in the same rock sample from kamafugite of Kasenyi (southwest Uganda, west branch of the East African Rift) were explored by electron probe microanalyses, single crystal X-ray diffraction and Mössbauer spectroscopy. Chemical analyses revealed close similarity both within and between the two polytypic arrangements as well as high TiO (~4.9 wt%) and AlO (~12.9 wt%), and low CrO (~0.8 wt%), F (~0.3 wt%) and BaO (~0.2 wt%) contents. Room temperature Fe Mössbauer investigation proved that the studied mica is a tetraferriphlogopite with: Fe = 19(1) %, Fe = 58(1) %, Fe = 23(1) %. Single crystal refinement showed that both polytypes have narrow range of variation in terms of some relevant unit cell parameters and similar values in terms of mean bond lengths, mean atomic numbers and distortion parameters. Similar substitutions were active in the structure of the 1 M and 2 M studied phlogopites. However, in 2 M polytypes the oxy-type substitutions were found to occur to a greater extent. Comparison of unit layer of 1 M mica (in the 2 M setting) with that of the 2 M ones showed that the 2 M polytypes are affected to different extent by relative shifts of the upper and lower triads of octahedral oxygens along the ± b directions. This effect did not cause any symmetry lowering in the T-O-T layer of the studied samples. [ABSTRACT FROM AUTHOR]

The crystal structures of tobelite and Due to image rights restrictions, multiple line equation(s) cannot be graphically displayed -rich muscovite from the sedimentary rocks of the Armorican sandstones (Brittany, France) have been solved for the first time by single-crystal X-ray diffraction. The structural study was integrated by electron probe microanalyses, and X-ray photoelectron and micro-Fourier transform infrared spectroscopy. The crystals belong to the 2M2 polytype with the following unit-cell parameters: a = 9.024(1), b = 5.2055(6), c = 20.825(3) Å, and β = 99.995(8)° for tobelite and a = 9.027(1), b = 5.1999(5), c = 20.616(3) Å, and β = 100.113(8)° for NH Due to image rights restrictions, multiple line equation(s) cannot be graphically displayed -rich muscovite. Structure refinements in the space group C2/c converged at R1 = 8.01%, wR2 = 8.84% and R1 = 5.59%, wR2 = 5.63% for tobelite and NH Due to image rights restrictions, multiple line equation(s) cannot be graphically displayed -rich muscovite, respectively. X-ray photoelectron spectroscopy revealed nitrogen environments associated either with inorganic (B.E. 401.31 eV) or organic (B.E. 398.67 eV) compounds. Infrared spectra showed, in the OH--stretching region (3700-3575 cm-1), two prominent bands, centered at ~3629 and ~3646 cm-1, and two shoulders at ~3664 and ~3615 cm-1 that were assigned to Al3+Al3+⇔-OH- arrangements having OH- groups affected by different local configurations. In addition, a series of overlapping bands from about 3500 to 2700 cm-1 characteristic of the NH Due to image rights restrictions, multiple line equation(s) cannot be graphically displayed -stretching vibrations, a main band at ~1430 and a shoulder at ~1460 cm-1 that were associated to the Due to image rights restrictions, multiple line equation(s) cannot be graphically displayed -bending vibration (v4) were also present. The ammonium concentration was semi-quantitatively estimated in both crystals from the absorbance of the OH--stretching and Due to image rights restrictions, multiple line equation(s) cannot be graphically displayed -bending vibrations in the infrared spectra. An additional estimate was obtained for the Due to image rights restrictions, multiple line equation(s) cannot be graphically displayed -rich muscovite by considering the normalized peak area between K2p3/2 and N1s in the X-ray photoelectron spectrum. The obtained values are in agreement with those derived from the interlayer spacing in the simulated X-ray powder diffraction spectra. The results of this integrated approach converged to Due to image rights restrictions, multiple line equation(s) cannot be graphically displayed for Due to image rights restrictions, multiple line equation(s) cannot be graphically displayed muscovite. [ABSTRACT FROM AUTHOR]

The crystal chemistry of 2M1 micas from Bunyaruguru kamafugite (southwest Uganda) was studied by electron probe microanalysis, single-crystal X-ray diffraction, Mössbauer and Fourier transform infrared spectroscopy. Chemical analyses showed that the studied crystals are Ti-rich, F-poor phlogo-pites with an annitic component, Fetot/(Fetot + Mg), ranging from 0.15 to 0.22. Unit-cell parameters from single-crystal X-ray data are in the range: 5.3252(1) ≤ a ≤ 5.3307(1), 9.2231(3) ≤ b ≤ 9.2315(3), 20.1550(6) ≤ c ≤ 20.1964(8) Å, and 94.994(2) ≤ β ≤ 95.131(2)°. Anisotropic structure refinements, in the space group C2/c, converged to 2.77 ≤ R1 ≤ 3.52% and 2.91 ≤ wR2 ≤ 4.02%. Mössbauer spectroscopy showed that the studied sample has: VIFe2+ = 60(1)%, VIFe3+ = 24(1)%, and IVFe3+ = 16(1)%. FTIR investigations pointed to the occurrence of Fe3+-oxy substitutions and ruled out the presence of vacancy mechanisms. The overall crystal-chemical features are consistent with the following substitutions: tetraferriphlogopite [IVFe3+ ↔ IVAl]; Ti-oxy [VIM2+ + 2 (OH)- ↔ VITi4+ + 2 (O2-) + H2↑] and Al, Fe3+, Cr-oxy [VIM2+ + (OH)- ↔ VIM3+ + O2- + ½ (H2)↑]; Al, Fe3+-Tschermak [VIM2+ + IVSi4+ , ↔ VIM3+ + IVAl]; kinoshitalite [XIIK + IVSi4+ ↔ XIIBa2+ + IVAl] and [XIIK+ + IVAl3+ ↔ IVSi4+ + XII□]. The estimation of the OH- content for Ugandan mica-2M1 was obtained, for the first time, from the linear regression equation c = 0.20(2) x OH- (gpfu) + 19.93(2) derived from literature data of 2M1-samples with known OH- content. The orientation of the O-H vector with respect to c* was found in the range from 2.0 to 6.9°. [ABSTRACT FROM AUTHOR]

The iron sulfate FeOHSO4 studied was obtained as a dehydration product of metahohmannite Fe2(H2O)4[O(SO4)2] during a synchrotron real-time powder diffraction experiment. As quoted in the literature, FeOHSO4 has iron atoms octahedrally coordinated with two hydroxyl groups and four sulfate O atoms, while each hydroxyl group is bonded to two iron atoms. This compound is commonly described in the orthorhombic system with space group Pnma, lattice parameters aJ = 7.33, bJ = 6.42, and cJ = 7.14 Å (aJ, bJ, and cJ are the Johansson lattice parameters), and Z = 4. However a preliminary Rietveld refinement of the pattern at about 220 °C using the structural model from the literature yielded a poor fit of the observed data and a final Rp value of about 23%. A careful analysis of the calculated powder diffraction pattern showed unexpected peaks, not observed in the experimental trace, for h = 2n + 1, while sharp reflections for h = 2n seemed to point to different lattice constants and space group. The recognition of the order-disorder character of the FeOHSO4 compound was the key to successfully interpreting the unexpected features of the experimental powder pattern and the misfit with respect to the calculated pattern. In fact, FeOHSO4 belongs to a family of OD structures formed by equivalent layers of symmetry Pbmm. Only two MDO (Maximum Degree of Order) polytypes are possible. MDO1 results from a regular alternation of stacking operators 2½ and 2-1/2, and yields an orthorhombic structure with space group Pnma and lattice parameters aJ = 7.33, bJ = 6.42, and cJ = 7.14 Å. MDO2 results from the 2½|2½|2½...sequence of symmetry operators and yields a monoclinic structure... [ABSTRACT FROM AUTHOR]

FINEAU (2021–2024) is a trans-disciplinary research project involving French, Serbian, Italian, Portuguese and Romanian colleagues, a French agricultural cooperative and two surface-treatment industries, intending to propose chènevotte, a co-product of the hemp industry, as an adsorbent for the removal of pollutants from polycontaminated wastewater. The first objective of FINEAU was to prepare and characterize chènevotte-based materials. In this study, the impact of water washing and treatments (KOH, Na2CO3 and H3PO4) on the composition and structure of chènevotte (also called hemp shives) was evaluated using chemical analysis, X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, X-ray computed nanotomography (nano-CT), attenuated total reflectance–Fourier transform infrared (ATR-FTIR) spectroscopy, solid state NMR spectroscopy and thermogravimetric analysis. The results showed that all these techniques are complementary and useful to characterize the structure and morphology of the samples. Before any chemical treatment, the presence of impurities with a compact unfibrillated structure on the surfaces of chènevotte samples was found. Data indicated an increase in the crystallinity index and significant changes in the chemical composition of each sample after treatment as well as in surface morphology and roughness. The most significant changes were observed in alkaline-treated samples, especially those treated with KOH. [ABSTRACT FROM AUTHOR]

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The thermal behavior of melanterite from the Fornovolasco mine (Tuscany, Italy) has been investigated via differential thermal analysis (DTA), thermogravimetry (TG), in situ high-temperature X-ray powder diffraction (XRPD) and Fourier-transform infrared spectroscopy (FTIR). The DTA curve showed endothermic peaks at 70, 100, 260, 500–560 and 660 °C whereas the TG curve evidenced a total mass decrease of ~68%, in keeping with the loss of all H2O and SO4 groups. Rietveld refinements were performed for all the collected patterns in the 25–775 °C range and converged at 1.57 ≤ R (%) ≤ 2.75 and 1.98 ≤ Rwp (%) ≤ 3.74. The decomposition steps FeSO4·7H2O → FeSO4·4H2O (25 ≤ T ≤ 50 °C) → FeSO4·H2O (50 < T ≤ 100 °C) → FeOHSO4 (75 < T ≤ 200 °C) → Fe2(SO4)3 (400 < T ≤ 500 °C) → Fe2O3 (500 < T ≤ 775 °C) were obtained. The high-temperature infrared analysis confirmed that melanterite undergoes a three-step dehydration in the 25–300 °C temperature range. The FeOHSO4 phase is stable over a wide range of temperature and transforms partially to Fe2(SO4)3 without the formation of Fe2O(SO4)2. The findings highlight a different behavior of the studied sample with respect to the synthetic salt. [ABSTRACT FROM AUTHOR]

The crystal structure of moganite from the Mogán formation on Gran Canaria has been re-investigated using high-resolution synchrotron X-ray diffraction (XRD) and X-ray/neutron pair distribution function (PDF) analyses. Our study for the first time reports the anisotropic atomic displacement parameters (ADPs) of a natural moganite. Rietveld analysis of synchrotron XRD data determined the crystal structure of moganite with the space group I2/a. The refined unit-cell parameters are a = 8.7363(8), b = 4.8688(5), c = 10.7203(9) Å, and β = 90.212(4)°. The ADPs of Si and O in moganite were obtained from X-ray and neutron PDF analyses. The shapes and orientations of the anisotropic ellipsoids determined from X-ray and neutron measurements are similar. The anisotropic ellipsoids for O extend along planes perpendicular to the Si-Si axis of corner-sharing SiO4 tetrahedra, suggesting precession-like movement. Neutron PDF result confirms the occurrence of OH over some of the tetrahedral sites. We postulate that moganite nanomineral is stable with respect to quartz in hypersaline water. The ADPs of moganite show a similar trend as those of quartz determined by single-crystal XRD. In short, the combined methods can provide high-quality structural parameters of moganite nanomineral, including its ADPs and extra OH position at the surface. This approach can be used as an alternative means for solving the structures of crystals that are not large enough for single-crystal XRD measurements, such as fine-grained and nanocrystalline minerals formed in various geological environments. [ABSTRACT FROM AUTHOR]

This study presents a cross-correlated surface and near surface investigation of two phlogopite polytypes from Kasenyi kamafugitic rocks (SW Uganda) by means of advanced Atomic Force Microscopy (AFM), confocal microscopy and Raman micro-spectroscopy. AFM revealed comparable nanomorphology and electrostatic surface potential for the two mica polytypes. A widespread presence of nano-protrusions located on the mica flake surface was also observed, with an aspect ratio (maximum height/maximum width) from 0.01 to 0.09. Confocal microscopy showed these features to range from few nm to several μm in dimension, and shapes from perfectly circular to ellipsoidic and strongly elongated. Raman spectra collected across the bubbles showed an intense and convolute absorption in the range 3000-2800 cm−1, associated with weaker bands at 1655, 1438 and 1297 cm−1, indicating the presence of fluid inclusions consisting of aliphatic hydrocarbons, alkanes and cycloalkanes, with minor amounts of oxygenated compounds, such as carboxylic acids. High-resolution Raman images provided evidence that these hydrocarbons are confined within the bubbles. This work represents the first direct evidence that phlogopite, a common rock-forming mineral, may be a possible reservoir for hydrocarbons. [ABSTRACT FROM AUTHOR]

The results of a combined electron probe microanalysis, single-crystal X-ray diffraction, and Fourier transform infrared study of a crystal of armstrongite from Khan Bogdo deposit (Gobi, Mongolia) are reported. Major element analysis provided (wt%): CaO 9.2(1), ZrO2 20.9(2), and SiO2 62.5(2). Significant concentrations of REE (0.45 wt%) were also detected. From single-crystal structural refinement, armstrongite resulted monoclinic [space group C2/m, a = 14.0178(7), b = 14.1289(6), c = 7.8366(3) Å, β = 109.436(3)°, V = 1463.6(1) ų, Z = 4] and twinned with two individuals rotated around a twin twofold axis parallel to [100]. The analyzed crystal was refined up to R = 3.3% (Rw = 2.9%). The structural refinement showed that the investigated armstrongite has only two water groups per formula unit consistent with the infrared analysis. Indeed, the occurrence in the infrared spectrum of the armstrongite (here reported for the first time) of two bending vibration bands at about 1640 and 1610 cm-1 testifies to the presence of two water groups environments. The results of this integrated approach converged to the following empirical formula (based on Si = 6 atoms per formula unit): (Ca0.96Ce0.01Yb0.01)Zr0.99Si6O14.97⋅2.02H2O. Finally, the studied mineral shows a framework density (FD = 21.86) lying in the range of zeolites and microporous heterosilicates with tetrahedral-octahedral frameworks. The determined crystal chemical features are relevant for the possible employment of this mineral or of its synthetic analogs for technological applications. [ABSTRACT FROM AUTHOR]

Volcanic activity at Mt. Vulture lasted about 750 ka and produced SiO2-undersaturated volcanic rocks that can be classified as old (~700 ka), intermediate (~600-550 ka), and young (~130 ka). The intermediate deposits consist of pyroclastic falls and flows and lavas with compositions ranging from phonolite to foidite. A recent revision of the stratigraphic setting allowed these deposits to be classified into one synthem (the Barile Synthem) and further subdivided into four subsynthems (Toppo S. Paolo, Rionero, Vulture-S. Michele, and Ventaruolo). In the present investigation, trioctahedral micas from sample VUT191 in the Vulture-S. Michele Subsynthem are considered. The host rock has modal diopside (20.2%), analcime (22.8%), plagioclase (27.8%), haüyne (5%), phlogopite (8.9%), and magnetite (6.3%). The micas were studied using chemical (EPMA, C-H-N, SIMS), structural (SCXRD), and spectroscopic (Mössbauer) methods. EPMA of 36 crystals from thin sections and 6 discrete crystals selected for the structural analysis showed remarkable compositional variability, as follows (in wt%): SiO2 = 33.14-38.01, Al2O3 = 15.56-20.45, MgO = 13.02-20.81, FeOtot = 6.34-14.08, TiO2 = 2.34-6.02, K2O = 6.03-9.48, Na2O = 0.50-0.78, and BaO = 0.89-4.06; all crystals proved to be phlogopite. Elemental C-H-N analyses yielded H2O = 2.86 ± 0.36 wt%. The water content was also determined by SIMS on two single crystals, labeled VUT191_2 and VUT191_19, which yielded values of 3.81 ± 0.12 and 1.72 ± 0.08 wt% H2O, respectively. Mössbauer investigation showed that all the iron in VUT191 mica is octahedral with Fe2+ = 25.5% and Fe3+ = 74.5%, confirming that Vulture micas are particularly Fe3+-rich, as also found from previous investigations. Structure refinements using anisotropic displacement parameters were performed in space group C2/m and converged at 1.89 ≤ R ≤ 3.17, 2.09 ≤ Rw ≤ 3.43%. All of the analyzed micas belong to the 1M polytype but exhibit remarkable variations in the c parameter from 10.1569(4) to 10.2458(4) Å. The chemical and structural parameters indicate that the studied micas can be divided into two groups: the first encompassing strongly dehydrogenated micas affected mainly by Ti-oxy [VIM2+ + 2(OH)- ↔ VITi4+ + 2O2- + H2] and M3+-oxy [VIM2+ + (OH)- ↔ VIM3+ + O2- + ½H2, with M3+ = Fe3+, Al3+] substitutions. The second group consist of samples in which vacancy-bearing mechanisms, 2 VIM2+ ↔ VITi4+ + VI⇔ and 3VIM2+ ↔ 2VIM3+ + VI⇔ occur. [ABSTRACT FROM AUTHOR]

Mt. Vulture trioctahedral micas-1M mainly consist of phlogopite-annite solid solutions with a minor component of brittle micas. However, both Li-free and Li- and F-rich compositions may coexist in the same volcano-stratigraphic level. We report the results of electron microprobe analysis (EMPA), secondary ion mass spectrometry (SIMS), and single-crystal X-ray diffraction (SCXRD) for three crystals (LC7-27Go, LC7-3Go, and LC7-1R) that are representative of both compositions. EMPA and SIMS showed that sample LC7-1R is richer in TiO2 , Li2O, and F and poorer in H2O than the other samples. Structure refinements using anisotropic displacement parameters for the three samples, performed in space group C2/m, converged at 3.46 ≤ R ≤ 4.34, 3.89 ≤ Rw ≤ 4.39. When considering bond distances, the three samples can be described as homo-octahedral whereas mean atomic numbers suggest that only LC7-1R is meso-octahedral. Significant differences occur among the samples for some distortion parameters commonly used for micas. In particular, LC7-1R displays higher values of BLDM2, shiftM2 and lower values of ΔK-O4 and tK-O4 than those of samples LC7-3Go and LC7-27Go. These differences are ascribed to F- and Ti-substitutions. Cation distributions were obtained by combining EMPA, SIMS, and SCXRD data after analysis of the effect of normalization schemes commonly used in mica formula recalculation. In LC7-3Go and LC7-27Go, Ti is incorporated according to the Ti-Tschermak mechanism, whereas more than one Ti-substitution mechanism occurs in LC7-1R. For the latter sample, octahedral vacancies are present leading to a complex substitution pattern and complex structural distortions related to the special octahedral compositions that were determined. [ABSTRACT FROM AUTHOR]