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The mineralogy and crystal chemistry of apatites occurring in 14 ejecta of historical eruptions (1631 and 1872 A.D.) of the Somma-Vesuvius volcanic complex were investigated by a multi-methodological approach including polarized optical microscopy, scanning electron microscope, electron microprobe analysis in wavelength-dispersive mode, laser ablation inductively coupled plasma mass spectroscopy, and single-crystal X‑ray diffraction. Five different groups of apatite, with different mineralogical and crystal-chemical features, were identified. Apatite crystals occur with well-developed hexagonal prismatic habit and, more rarely, with skeletal acicular forms. The crystals are yellow (type 1), transparent and colorless (type 2 and type 3), green (type 4) and aquamarine colored (type 5), with different paragenesis: macro-crystalline aggregates of clinopyroxenes, phlogopite, and apatite (type 1; type 4); clusters of apatite with micro-crystalline clinopyroxene, minerals of the cancrinite group, feldspars, and opaque minerals (type 2); aggregates of apatite, sellaite, wagnerite, gypsum, and phlogopite (type 3); aggregates of davyne, nepheline, mica group minerals, and apatite (type 5). Chemical analyses of apatites show variable amounts of Na, REE, Mg, Sr, and Fe replacing Ca, not negligible amounts of Si and S substituting P, and a significant substitution of Cl and OH instead of F. Five crystals representative of each apatite-type were studied by single-crystal X‑ray diffraction. Their crystal structure was refined in the hexagonal P63/m space group. A significant variation of the unit-cell parameters with the composition was observed. A comparative crystal-chemical analysis between apatites from Somma-Vesuvius and those from other localities is carried out

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The elusive hydroxylammonium lead iodide NH3OHPbI3 has been successfully synthesized and characterized for the first time.

This communication reports on the possibility to achieve the direct production of either carbamazepine crystals or carbamazepinesaccharin cocrystals from water/ethanol solvent mixtures by using membrane-based crystallization technology, by choosing the opportune initial conditions.Co-crystallization of active pharmaceutical ingredients (APIs) with cocrystal formers 1 (or conformers) has become increasingly important in the last few years in the drug-development process, primarily because it provides an alternative to the physical properties of the neat API solid phases. [2][3][4] Co-crystals offer a much wider range of solid forms and improved properties than the solid forms of the free API and its salts, such as shelf life, 5 dissolution rate, 6 and bioavailability. 7,8 Furthermore, co-crystallization offers potential to tailor the physicochemical properties of a drug preparation to an optimum specification, with remarkable consequences also in the field of the intellectual properties protection. 9The most economical and easiest method to scale up for cocrystals production is crystallization from solution. 10,11 However, its apparent failure in a number of cases 12,13 has led to the exploration of other approaches, like spray drying involving supercritical fluid, 14 solidstate grinding, and solvent drop grinding 15 techniques, as alternatives to solution crystallization. [16][17][18] These latter processes under several aspects are not well-understood nor adequately controlled, making cocrystals formulation a kind of empirical and mysterious preparative methodology. Such a description demonstrates on the one side the formidable technological/economical implications in enhancing the knowledge about cocrystals preparation procedures but, on the other side, it demands the development of new and more efficient production technologies.