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A series of lead(II) complexes incorporating benzoate derivative ligands was prepared: [Pb(2MeOBz)2]n (1), [Pb(2MeOBz)2(H2O)]n (2), [Pb2(1,4Bzdiox)4(DMSO)]n (3), [Pb(1,4Bzdiox)2(H2O)]n (4), [Pb(Pip)2(H2O)]n (5), and [Pb(Ac)(Pip)2(MeOH)]n (6) (2MeOBz: 2-methoxybenzoate; 1,4Bzdiox: 1,4-benzodioxan-5-carboxylate; DMSO: dimethylsulfoxide; Ac: acetate; Pip: piperonylate; MeOH: methanol). All compounds were characterized via elemental analysis, ATR-FTIR spectroscopy, and powder XRD. In addition, the crystal structures of some compounds were elucidated. Compounds 1 and 2, involving 2-methoxybenzoate, were closely related, only differing in the presence of one extra aqua ligand found for the latter. However, this implies key changes in the studied properties, e.g., 2 shows solid-state luminescence that displays a different color as a function of the crystal orientation, while 1 does not. The crystal structure of 2 revealed a 1D coordination polymer. A similar relationship was found between compounds 3 and 4, incorporating 1,4-benzodioxan-5-carboxylate. In this pair, only 4, with aqua ligands, displayed a greenish-yellow-color solid-state luminescence. Furthermore, two new lead(II) piperonylate complexes, 5 and 6, were obtained from the reaction between lead(II) acetate and piperonylic acid. In water, all acetate ligands in the metal precursor were displaced and [Pb(Pip)2(H2O)]n (5) was isolated, while in methanol, a mixed acetate–piperonylate complex, [Pb(Ac)(Pip)2(MeOH)]n (6), was precipitated. Considering only conventional Pb-O bonds, the crystal structure of 6 was described as a 1D coordination polymer, although, additionally, the chains were associated via tetrel bonds, defining an extended 2D architecture. [ABSTRACT FROM AUTHOR]

The reaction between 2,4,6‐tris(4‐pyridyl)‐1,3,5‐triazine (4‐tpt) and copper(II) hexafluoroacetylacetone (Cu(hfa)2) yields two different 1D metal–organic frameworks (MOFs), [(Cu(hfa)2)2(4‐tpt)]n (1) and [Cu(hfa)2(4‐tpt)]n (2). The Cu:4‐tpt ratio in the new MOFs is determined by the reaction medium, particularly, the solvent used. The two compounds have been fully characterized, including crystal structure elucidation. [(Cu(hfa)2)2(4‐tpt)]n (1), with a 2:1 Cu:4‐tpt ratio, could be precipitated in either 1,1,2‐trichloroethane or supercritical CO2. In (1), 4‐tpt shows a tritopic coordination mode, but only half of the Cu(hfa)2 subunits act as a node, thus connecting two 4‐tpt and giving a 1D network. The other half of Cu(hfa)2 subunits are connected only to one pyridine and thus protrude along the chains. The later Cu(hfa)2 fragments show a labile character and can be dissolved in diethyl ether to give the second MOF [Cu(hfa)2(4‐tpt)]n (2), with a 1:1 Cu:4‐tpt ratio. The compound (2) has also a 1D structure, with all the incorporated copper atoms acting as nodes. In this case, the packing of the chains defines accessible channels, which are perpendicular to the chain axis. After activation, N2 adsorption/desorption measurements at 77 K confirm the microporous character of (2) with an apparent surface area of 190 m2 g−1. Besides, at 273 K this material clearly shows a significant adsorption of CO2 prompted by noncoordinated nitrogen in the triazine linker. [ABSTRACT FROM AUTHOR]

The use of acetic acid as neat solvent in the synthesis of coordination polymers using trimesic acid and metal acetates has been proved for different metals. 2D compact coordination polymers were obtained for cobalt, [Co 6 (BTC) 2 (Ac) 6 (HAc) 3 ], which incorporates both acetic acid and acetate ligands, and for bismuth, [Bi(HBTC)(Ac)]. Nowadays, there is a great interest in the design of new metal–organic frameworks (MOFs) synthetized by routes that can be transferred to industrial scale with low environmental impact. In this context, this work explores the use of a soft method for the synthesis of MOFs, in which neat acetic acid is used as the reaction media. Trimesic acid (H 3 BTC) was chosen as the organic linker source and combined with different metal acetates, all these precursor being moderately soluble in hot acetic acid. The metal acetate provides both the metallic cation and a base, the acetate, necessary to deprotonate the H 3 BTC. Three first row transition metals, Cu, Co and Ni, and one heavy metal, Bi, were chosen for the study. Results denoted that the metal acetate was determinant to direct the nature of the precipitated material. For instance, the precipitation of the well-known porous HKUST-1 was observed from Cu acetate and H 3 BTC in neat acetic acid, giving systems with hierarchical porosity. Contrarily, for Co and Bi the use of acetic acid as a solvent yielded two 2D non porous coordination polymers, [Co 6 (BTC) 2 (Ac) 6 (HAc) 3 ] (1) and [Bi(HBTC)(Ac)] (3), respectively. These new compounds were structurally elucidated. Moreover, the magnetic behaviour was analysed for the Co compound (1). Finally, an amorphous phase was precipitated for Ni. In the latter case, the use of propionic acid, with a higher boiling point than acetic acid, led to the precipitation of a crystalline material. [ABSTRACT FROM AUTHOR]

The d2Dplot computer program provides a set of tools for the visualization, processing and analysis of 2D X‐ray diffraction (2DXRD) data. Among the operations available there are the sum/subtraction of 2DXRD images, conversion to 1D data (powder pattern), azimuthal plotting, calibration of instrumental parameters, background subtraction and a command‐line mode to run operations inside data processing pipelines. The graphical user interface allows easy use of the program. It also includes two main features: (i) the possibility of creating a user compound database to help in the fast phase identification of similar samples, and (ii) a detailed peak analysis routine for the application of the through‐the‐substrate microdiffraction methodology. d2Dplot is a computer program for the visualization and processing of 2D X‐ray diffraction data including a user‐created compound database and a peak analysis routine for the application of the through‐the‐substrate microdiffraction methodology. [ABSTRACT FROM AUTHOR]

Two copper(II) complexes, both involving the anionic 3,5-bis(trifluoromethyl)benzoate ligand (TFMBz), have been prepared and their structure elucidated by single crystal-X ray diffraction. [Cu(TFMBz) 2 (ISNA) 2 ] (1) is a mononuclear complex, in which the sphere of coordination of Cu(II) is completed by two neutral isonicotinamide (ISNA) auxiliary ligands. Hydrogen bonding formed between auxiliary ISNA ligands determines the formation of a 2D supramolecular network. [Cu 2 (TFMBz) 4 (DMSO) 2 ] (2) is a binuclear complex, in which the four carboxylate ligands define the typical paddle wheel structure often found in copper complexes, containing also the ancillary dimethyl sulfoxide (DMSO) ligand in axial positions. The elucidated crystallographic data provide the static view of the crystal structures, which reveals only non-interconnected voids for both materials. Even that, compound 1 shows an appreciable adsorption of CO 2 at 273 K (ca. 1 CO 2 molecule/Cu atom at 100 kPa), concomitant with a reduced adsorption of Ar or N 2 under similar conditions, which implies a considerable degree of selectivity for CO 2. Moreover, 1 does not adsorb N 2 or Ar at 77 K and 100 kPa. This behavior suggests that the stablished intermolecular hydrogen bonds rest flexibility and dynamism to 1 at low temperature. Contrarily, increasing the temperature transient porosity is originated, which allows guest molecules to diffuse through the cavities. Compound 2 shows adsorption of N 2 and Ar at 77 K, indicating that vibrations in the network and rotation of some CF 3 groups, necessary to favor adsorbate diffusion, are still feasible at this low temperature. [Display omitted] • Two new porous molecular crystals (PMCs) were synthetized and their crystal structures were solved. • Dynamic porosity explains significant adsorption involving guest diffusion trough apparently isolated voids. • Intermolecular forces determine the temperature necessary to promote dynamic porosity. [ABSTRACT FROM AUTHOR]

Successful phasing of synchrotron through-the-substrate microdiffraction data by δ-recycling direct-methods largely depends on the number of missing intensities caused by the limited sample rotation range [J. Rius, Direct phasing from Patterson syntheses by δ recycling. Acta Cryst. A 2012, 68, 77-81]. Particularly, for the unfavorable triclinic system, dataset completeness resulting from a single series of consecutive φ-scans covering a total φ interval of ±35° is around 41%. This value is not enough for the routinary solution of a crystal structure by δ-recycling but can be increased by ~29% by applying the orthogonal χ strategy consisting of merging the information of two series of orthogonal φ-scans collected at the same microvolume of the polished thin section. Test calculations using simulated and experimental tts-data of the triclinic mineral axinite confirm that, with the help of the orthogonal χ strategy, crystal structures can be solved routinely. Since data in the ±35 φ-interval are normally accessible even for relatively thick glass-substrates (1-1.5 mm), a crystal structure can be determined from a single microvolume. For high-symmetry phases, due to the Laue symmetry redundancy, a single series of φ-scans normally suffices for the application of δ-recycling. However, when for experimental causes this series is incomplete, the orthogonal χ strategy also provides a simple way to increase the completeness which besides allowing solving the structure, is also beneficial for the subsequent refinement. [ABSTRACT FROM AUTHOR]

The hydrocarboxylation of allyl cyanide with monodentate phosphine systems (Pd/triphenylphosphine and protic acid cocatalyst) gave branched 3-cyano-2-methylpropanoic acid chemo- and regioselectively, whereas with bidentate systems (Pd/bis[(2-diphenylphosphino)phenyl] ether and protic acid cocatalyst) it gave linear 4-cyanobutanoic acid chemo- and regioselectively. 3-Cyano-2-methylpropanoic acid and 4-cyanobutanoic acid were isolated in high yields as carboxylic acids and purified as benzyl esters. No isomerization of allyl cyanide to crotononitrile or its carbonylated derivatives was observed in any case. In parallel experiments, deuterocarboxylation under the same conditions gave the corresponding deuterated products, which were analyzed by MS and 2H NMR spectroscopy: only d0, d1, and d2 products were detected. Deuterium entered the β and γ-CN positions of the products but never the α position. [ABSTRACT FROM AUTHOR]

An innovative crystallization process, based on the use of the ecofriendly supercritical carbon dioxide (scCO2) solvent, is presented for the production of coordination compound macrocrystals of general formula [Cu(hfacac)2(dPy)2], with intriguing prismatic hollow structures and single polymorphic forms. In contrast, conventional solvents yielded compact microstructures. The studied pyridine derivatives (dPy) were 4-phenylpyridine, PhPy; 4-benzylylpyridine, BzPy; and 4-acetylpyridine, AcPy. In the specific case of the [Cu(hfacac)2(AcPy)2] adduct, the use of scCO2 as a solvent allowed obtaining a pure polymorph, while the conventional solvent trials yielded a mixture of two polymorphs. Four new crystalline structures have been resolved from single crystal X-ray diffraction. All the structures consist of mononuclear complexes connected through intermolecular interactions, including H···H, H···O, F···F, C-F···Caromatic, and/or C-F···π interactions, generating bi-dimensional networks that determine their crystallization mode in scCO2. [ABSTRACT FROM AUTHOR]

Catalysis of the oxidative processes by iodoarenes has become a promising direction in synthesis. The mechanism, involving the well-known isolable hypervalent iodine species, is generally limited to aromatic iodides, since the corresponding aliphatic species are normally highly unstable. Nevertheless, in this work catalytic amount of several primary, secondary or tertiary iodoalkanes were found to promotes the α-tosyloxylation of a range of ketones with RSO3H, including aliphatic sulfonates. The process, was found to proceed through the oxidative breakdown of the iodoalkane to an inorganic catalytic species (likely IO− or IO2−), thus falling within the previously described catalysis using molecular iodine or inorganic iodides. The catalyst eventually becomes deactivated through the precipitation of an iodine overoxidation product, the structure of which was solved ab initio from the powder diffraction data as a hitherto unreported phase of the iodic acid (HIO3). [ABSTRACT FROM AUTHOR]

TALP is a new direct-space strategy for ab initio crystal structure determination of molecular crystals from powder diffraction data. The strategy is based on a preliminary exploration stage, which considers atomic overlap, followed by a subsequent stage of local incremental scans, both coupled to fast restrained least-squares minimizations with the atomic coordinates as refined parameters. The observed intensities are extracted from the powder pattern by a three-step procedure [Vallcorba, Rius, Frontera, Peral & Miravitlles (2012). J. Appl. Cryst. 45, 844-848], and the molecular model and distance restraints are derived from molecular mechanics calculations or from similar reported structures. The solution process consists of several independent trials, each one resulting in a crystal structure proposal with an associated figure of merit. TALP has been tested on laboratory X-ray powder diffraction data of 14 molecular compounds of known crystal structure and of variable complexity. In most cases, the crystal structure is solved in a short time (less than an hour), even for calculated models. For the most complex structures ( e.g. 13 torsion angles), the general scan is assisted by a rotation function, which provides a ranked list of most probable model orientations. In this way only the positional and conformation parameters need to be explored. [ABSTRACT FROM AUTHOR]

DAJUST is the generic name of a software package for powder diffraction formed by the core programs AJUST and SGAID (both written in Fortran) controlled by an easy-to-use Java user interface ( DAJUST_UI). While AJUST performs whole-pattern matching (cell-parameter refinement, profile fitting and intensity extraction), SGAID provides a list of the most probable space groups. For the extraction of the integrated intensities, AJUST uses the Le Bail procedure but with a different formula for refining the integrated intensities. Laboratory, synchrotron X-ray and neutron sources, and both reflection and transmission experimental geometries, are supported. Other program options include automated background estimation, asymmetry correction, and corrections for absorption, variable divergence and/or illumination. The extracted intensity data are written in text format and can be directly processed by the direct methods program XLENS [Rius (2011). Acta Cryst. A 67, 63-67] and the multisolution direct-space structure determination program TALP [Vallcorba, Rius, Frontera & Miravitlles (2011). Acta Cryst. A 67, C272]. [ABSTRACT FROM AUTHOR]

• The reaction between Zn(II) acetate and the flexible N,N'-ditopic ligand, 1,4-bis(4-pyridylmethyl)benzene has been performed. • The two different bridging ligands, acetate and bpymb, allows the formation of a 2D net. • [Zn 2 Ac 2 (m-Ac) 2 (bpymb)] n is a luminescent product. The combination of the flexible N,N'-ditopic ligand 1,4-bis(4-pyridylmethyl)benzene (bpymb) with zinc(II) acetate (ZnAc) affords the synthesis of the two-dimensional coordination polymer [Zn 2 Ac 2 (μ-Ac) 2 (bpymb)] n , which was structurally characterized by single crystal XRD. In the resolved structure, the molar ratio metal:ligand was 2:1 for Ac:Zn. However, half of the acetate units are acting as bridging ligands, which allows the building of a layered structure. The description of this new structure increases the numerous family of compounds involving zinc acetate and a ditopic N,N'- ligand, and demonstrates a new possible architecture. The obtained coordination polymer was also characterized by elemental analysis, ATR-FTIR spectroscopy and TGA analysis. Besides, the photoluminescence properties of this compound where measured, showing that the weak photoluminescence of the free bpymb ligand increases after polymer formation. [ABSTRACT FROM AUTHOR]

New excavations at Espidej at the Kerman Province of the Halil Basin corridor in Iran offer a unique opportunity to reconsider the third millennium BC (i.e. Bronze Age) metallurgical practices related particularly to arsenical copper (Cu‐As) alloying and to explore arsenic‐bearing raw materials. This paper presents results of optical microscopy and environmental scanning electron microscopy (ESEM) on a selected group of copper‐based artefacts from Espidej. Additionally, we have benefited from synchrotron light for further investigations on a dagger sample. The scientific examinations on metal corpora adds new information regarding the microchemistry and production techniques of metals of the south‐eastern cultural zone of Iran. Synchrotron micro X‐ray diffraction (SR‐μXRD) data of the sample demonstrates traces of arsenic‐bearing minerals in the corrosion products indicative of types of ores used in alloying processes. Preliminary research on copper ores indicates possible extraction of local ore deposits that were outcropped along the south‐east Makran orogeny zone of Iran. This area is part of hydrothermal mineralization zone consisting of arsenopyrite (FeAsS), sinnerite (Cu6As4S9), bornite (Cu5FeS4) and algodonite (Cu6As). Noticeable arsenic‐bearing phases within the metallic core of the sample were frequently characterized as sinnerite and algodonite. [ABSTRACT FROM AUTHOR]

The title compound, C21H14N4O2S, belongs to a family of molecules possessing nonlinear optical properties in solution. Its structure has been solved from laboratory X-ray powder diffraction data using a new direct-space structure solution method, where the atomic coordinates are directly used as parameters and the molecular geometry is described by restraints. The molecular packing is controlled by two systems of π-π interactions and one weak edge-to-face interaction. [ABSTRACT FROM AUTHOR]

This paper provides a detailed technological characterization of the Roman opus sectile glasses (second century AD) coming from the renowned Gorga collection. Nine glass samples corresponding to imitations of the porfido verde antico, cipollino rosso, rosso antico, giallo antico, diaspro nero e giallo, semesanto and agate/alabaster stones were studied. The aim of this study was twofold: (i) archaeometric, i.e., to provide valuable data on the production, raw materials and techniques of these refined Roman glasses that mimic precious stones and (ii) methodological, i.e., to highlight the good performance of combining polished thin sections and local probe measurements for the study of glassy microstructures. Based on the nature of the flux used, the glasses from the samples were classified as either natron-type or mixed-type (natron/plant ash). The latter stem from remelted glasses and contain relict grains of wollastonite that were not found in the pure natron samples. Relict wollastonite crystals appear to be a proficient petrographic marker to spot recycled glasses along with the commonly used chemical fingerprints. Different production and colouring techniques were identified, even for a given type of imitated stone. Metallic Cu, Ca antimonates and Pb-Fe antimonates were the three opacifiers used for the opaque glasses. Based on the crystal morphologies, metallic Cu and Ca antimoniates were possibly synthesized in situ simultaneously with the glass, whilst the Pb-Fe antimonates were prepared ex situ. The working temperatures for these glasses were estimated within the 900–1100 °C range based on the presence and known thermal stability of some identified crystal phases. [ABSTRACT FROM AUTHOR]

We report the X-ray solid state structures of four new squaric acid derivatives, i.e. three polymorphs of 3,4-bis((2-(dimethylamino)ethyl)amino)cyclobut-3-ene-1,2-dione (1a–c) and a co-crystal of compound 1 and resorcinol (2). All structures form interesting supramolecular assemblies in the solid state which have been analyzed using high level DFT calculations and molecular electrostatic potential (MEP) surface calculations. A combination of H-bonding and π–π stacking interactions of the cyclobutenedione rings are crucial for the formation of the supramolecular assemblies in the solid state. Moreover, unusual antiparallel CO…CO interactions observed in the X-ray structure of one of the polymorphs of 1 and the lp–π interactions between one oxygen atom of resorcinol and the squaramide ring in 2 have been characterized using Bader's theory of “atoms-in-molecules” (AIM). [ABSTRACT FROM AUTHOR]

Ag2Cu3Cr2O8(OH)4, a new Ag–Cu–Cr–O layered mixed oxide, prepared by soft hydrothermal heterogeneous reactions, is reported. The new phase is an oxyhydroxide and presents a structure with alternating brucite-like Cu–O and Ag–O layers connected by individual chromate groups. The crystallographic structure has been solved and refined from high resolution powder X-ray diffraction data and is supported by density functional theory calculations, yielding a triclinic, space group P1̅, a = 5.3329(1) Å, b = 5.3871(1) Å, c = 10.0735(1) Å, α = 80.476(1)°, β = 87.020(1)°, γ = 62.383(1)°. Bond valence sums suggest the formulation of Ag+2Cu2+3Cr6+2O8(OH)4, an electronic state fully supported by X-ray photoelectron spectroscopy (XPS) and Cr K-edge X-ray absorption near edge structure (XANES) measurements. Ag2Cu3Cr2O8(OH)4 exhibits bidimensional Cu–O–Cu ferromagnetic correlations that are apparent at much higher temperatures than in other similar Cu–O layered structures, without coupling between Cu–O layers, which represents a unique case in the recent family of silver copper oxides. The role of Ag inducing bidimensionality in copper oxides is therefore expanded further with the presence of chromate anions. Ab initio calculations using density functional theory show that the electronic states involved originate mainly from Cu and OH orbitals, with minor contributions from Cr and the O atoms linking the Cr tetrahedra to the brucitic Cu–O layer, and almost no contribution from Ag. Further modeling of the in-plane magnetic interactions between Cu atoms suggests that the coupled magnetized stripes are responsible for the observed behavior. The results are discussed in relation with previous Ag–Cu mixed oxide phases where metallic behavior or ferro–antiferro transitions had been observed. The structure of this new Ag–Cu–O phase as compared with previous silver copper oxides supports the conclusion that the Ag–Cu layered ordering is favored under oxidizing conditions. [ABSTRACT FROM AUTHOR]

Herein we explore the opportunities arising from combining bicyclic amine cations with halometallate anions to build organic–inorganic hybrid materials. We will use the crystal engineering approach in these materials, focusing on the tuning of the organic cation, which is mainly responsible for obtaining both new plastic states at high temperature and electrical behaviour below the plastic temperature. Precisely, this work explores the influence of the ketonization of the bicyclic quinuclidine molecule (C7H13N)+, which, combined with the tetrachloroferrate(1-) anion, gives the compound (3-oxoquinuclidinium)[FeCl4]. Interestingly, crystallization in the presence of humidity is enough to obtain an isostructural hydrate phase of formula (3-oxoquinuclidinium)[FeCl4]·H2O. Although the organic–inorganic layered structure is the same in both compounds, the three-dimensional magnetic ordering disappears after the intercalation of crystallization water molecules. A heat treatment above 400 K allows the removal of water obtaining the non-hydrate phase. Finally, the temperature evolution of the electric and magnetic behaviour will be compared with other previously reported hybrid organic–inorganic materials built with tetrachloroferrate ions and quinuclidinium-based cations. [ABSTRACT FROM AUTHOR]

Teeth provide information about the evolutionary pathway of an organism, its biology and habitat. This is the case even of fossilized teeth, since they have perdurable biomineralized structures, as biological apatite. The material that has been selected for this study comprises teeth from modern crocodilian individuals and extinct Cretaceous crocodylomorphs from Lo Hueco site. Microanatomy, histochemistry and crystallographic nature of enamel, dentine and cementum have been characterized by Polarized Light Microscopy, SEM-EDS, Confocal Raman Spectroscopy and SR-µXRD. A focus has been made on dentine lamination. In the fossil sample short-period incremental lines show alternate presence of dentinal tubules that has not been described previously either in living or fossil archosaur. This could be related to influence of environmental circadian rhythms in the abundance, size and/or activity of cells depositing dentine in the day-night cycle. Regarding histochemical and crystallographic compositions, the major and mostly unique phase is HA, but in the case of fossil teeth, a secondary phase identified as hematite appears locally between discontinuities of the material. Incremental lines would not be related to variation in chemical composition and furthermore do not present different HA crystallographic nature (different directions of HA or different crystallite sizes) either. Only small intensity oscillations are observed in the fossil sample by SR-µXRD which are compatible with the alternating abundance of dentinal tubules. Crystallinity differences between modern and fossil material, as crystallite size and presence of CO3 2- groups could be explained by postdepositional processes. [ABSTRACT FROM AUTHOR]

A new magnetic ionic liquid (MIL) with 3D antiferromagnetic ordering has been synthetized and characterized. The information obtained from magnetic characterization was supplemented by analysis of DFT calculations and the magneto-structural correlations. The result gives no evidence for direct iron-iron interactions, corroborating that the 3D magnetic ordering in MILs takes place via super-exchange coupling containing two diamagnetic atoms intermediaries. [ABSTRACT FROM AUTHOR]

Abstract: We have synthesized a novel hexaaza[5]helicene in a straightforward way from neocuproine. The crystal structure has been elucidated with direct-space strategy TALP which demonstrates the power of the powder X-ray diffraction technique. In this crystal structure it is possible to see an interplanar angle of 33(1)° between the two triazolopyridine rings. The centrosymmetric crystal structure is a racemic mixture, but the resolution was not possible due to a ring-chain isomerization in a solution that produces a dynamic racemization. [Copyright &y& Elsevier]

δ Recycling is a simple procedure for directly extracting phase information from Patterson-type functions [Rius (2012). Acta Cryst. A 68, 399-400]. This new phasing method has a clear theoretical basis and was developed with ideal single-crystal X-ray diffraction data. On the other hand, introduction of the automated diffraction tomography (ADT) technique has represented a significant advance in electron diffraction data collection [Kolb et al. (2007). Ultramicroscopy, 107, 507-513]. When combined with precession electron diffraction, it delivers quasi-kinematical intensity data even for complex inorganic compounds, so that single-crystal diffraction data of nanometric volumes are now available for structure determination by direct methods. To check the tolerance of δ recycling to missing data-collection corrections and to deviations from kinematical behaviour of ADT intensities, δ recycling has been applied to differently shaped nanocrystals of various inorganic materials. The results confirm that it can phase ADT data very efficiently. In some cases even more complete structure models than those derived from conventional direct methods and least-squares refinement have been found. During this study it has been demonstrated that the Wilson-plot scaling procedure is largely insensitive to sample thickness variations and missing absorption corrections affecting electron ADT intensities. [ABSTRACT FROM AUTHOR]

Nephrolithiasis is a multifactor disease that produces nephrolites in the kidneys. Calcium oxalate hydrate (dihydrated, COD, or monohydrated, COM) stones are the most common ones with more than sixty percent incidence worldwide. They are related to different pathologies, COD with hypercalciuria and COM with hyperoxaluria. COD is an unstable species and transforms into COM (herein named TRA to distinguish the origin of the monohydrated species). TRA and COM are chemically and crystallographically identical leading to misdiagnosis and recurrence increase. In the current study, the composition and crystalline structures of several calcium oxalate stones, classified by morpho-constitutional analysis, were examined by IR and synchrotron through-the-substrate micro-X-ray diffraction (tts-μXRD). Both IR and linear diffractogram studies were able to distinguish between the monohydrated and dihydrated phases but not between COM and TRA, as expected. The analysis of 2D diffraction patterns revealed that TRA showed a lower degree of crystallinity and less texture with respect to COM which can be used as a signature to distinguish between the two. This study confirms that despite the subtle differences between COM and TRA, the origin of the monohydrate oxalates can be unraveled using tts-μXRD. This valuable information should be taken into account in order to improve patients' diagnosis and reduce recurrence by considering and treating the origin of the formed stones. [ABSTRACT FROM AUTHOR]

The ammonium salt of monoethyloxalate (AmEtOx) was investigated as a novel precursor for the conservation of carbonate stone substrates, such as biomicritic limestone and marble. Full characterization of treated and untreated authentic stone samples was carried out by means of SEM, X-ray powder diffraction, synchrotron tts-μXRD measurements, mercury intrusion porosimetry, determination of water transport properties, and pull-off tests. The improved solubility (1.49 M, 20.1% w/w) of AmEtOx as compared to that of ammonium oxalate (AmOx; 0.4 M, 5% w/w) results in the formation of microcrystalline phases 30–50 and 200–500 μm thick of calcium oxalate mono-(whewellite) or dihydrate (weddellite), on marble and biomicrite samples, respectively, after treatment with AmEtOx 5% and 12% w/w aqueous solutions. As a result, a reduction in the porosity of the stone samples and an enhancement of their cohesion are observed. DFT calculations, carried out to investigate the hydrolysis reaction leading from AmEtOx to AmOx, showed that the localization of the Lowest Unoccupied Molecular Orbital (LUMO) and the natural charge distribution account nicely for the tendency to hydrolyse observed experimentally, eventually leading to the formation of whewellite and weddellite on the stone surface. [ABSTRACT FROM AUTHOR]

• Development of silica microcrystals is inferred from morphology and local probe data. • Cristobalite and tridymite can nucleate from iron oxide not requiring alkali metals. • Morphology of silica microcrystals can hide intergrowths and paramorphic phases. • Cristobalite hexagonal plates and dendrites show a tridymite external growth front. Different methods have been historically used to identify silica-polymorph microcrystals in various contexts. However, in the existing literature there is a substantial lack of correlation between local probe analytical data and the corresponding images showing crystal morphologies. Here we demonstrate that such correlation is attainable through an approach based on the characterization of samples prepared as polished thin sections combining optical microscope images with local probe techniques (synchrotron through-the-substrate X-ray microdiffraction and confocal micro-Raman). We report the characterization of different morphologies of silica microcrystals embedded in lead glazes from glazed pottery produced in Jouques (France) in the mid-19th century. Among the eight identified morphologies, are worthy of note cristobalite-coated quartz, paramorphic quartz after cristobalite, cristobalite-tridymite intergrowths or cristobalite twinned crystals. Elusive tridymite has been identified and mapped using μ-Raman and locates predominantly at the borders of some morphologies suggesting a growth front of tridymite that turns to cristobalite. [ABSTRACT FROM AUTHOR]

Coloured enamels from the materials used in Modernist workshops from Barcelona were produced and compared to those found in the buildings to explore the reason for the reduced stability of the blue and green enamels. They were made of a lead-zinc borosilicate glass with a low softening point, reasonable stability to corrosion and matching thermal expansion coefficient with the blown base glass, mixed with colourants and pigment particles. The historical enamels show a lead, boron and zinc depleted silica rich amorphous glass, with precipitated lead and calcium sulphates or carbonates, characteristic of extensive atmospheric corrosion. The blue and green enamels show a heterogeneous layered microstructure more prone to degradation which is augmented by a greater heating and thermal stress affectation produced by the enhanced Infrared absorbance of blue tetrahedral cobalt colour centres and copper ions dissolved in the glass and, in particular, of the cobalt spinel particles. [ABSTRACT FROM AUTHOR]

Combined high pressure single crystal X-ray diffraction experiments and ab initio simulations based on the density functional theory have been performed on a copper(I) iodide cluster formulated [Cu4I4{PPh2(CH2CH = CH2)}4] under high pressure up to 5 GPa. An exhaustive study of compressibility has been done by means of determination of isothermal equations of state and structural changes with pressure at 298 K taking advantage of the single crystal is more precise than powder X-ray diffraction for this type of experiments. It allows us to report the evidence of the existence of an isostructural phase transition of second order at 2.3 GPa not detected so far. [ABSTRACT FROM AUTHOR]

Abstract: Galena, also known as PbS, was widely used in the production of lead glazes from the beginning of the 18th century to the second half of the 20th century. Although the PbO‐SiO2 system has been studied for years, the PbS–SiO2 phase diagram, involved in the formation of a glaze with galena, has not yet been investigated. Temperature transformations for the system 75 wt% PbS‐25 wt% SiO2 are investigated in a high‐temperature resolved X‐ray diffraction experiment with synchrotron radiation and compared to those of the equivalent system 70 wt% PbO‐30 wt% SiO2. Lanarkite, PbO·PbSO4, is the phase predominantly formed as soon as galena decomposes during the heating. The results show that the system melts at a temperature higher than the PbO–SiO2 system, but far lower than those expected for the PbO–PbSO4–PbS system. A historical misfired lead glaze produced with galena is also studied. The presence of galena, lanarkite, and mattheddleite, Pb10(SiO4)3.5(SO4)2Cl2, is determined and discussed in terms of the composition of the galena mineral used and the firing conditions in light of the high‐temperature transformations previously obtained. [ABSTRACT FROM AUTHOR]

Abstract: The characterization of the crystal structure, phase transitions, magnetic structure and dielectric properties has been carried out on [CH3NH3][Co(COOH)3] (1) perovskite‐like metal–organic compound through variable‐temperature single‐crystal and powder neutron and X‐ray diffraction and relative permittivity measurements. The paraelectric to antiferroelectric‐like phase transition observed at around 90 K is triggered by a structural phase transition; the structural studies show a change from Pnma space group at RT (1A) to P21/n space group at low temperature (1B). This phase transition involves the occurrence of small distortions in the framework and counterions. Neutron diffraction studies have shown a magnetic order showing spontaneous magnetization below 15 K, due to the occurrence of a non‐collinear antiferromagnetic structure with a weak ferromagnetic component, mainly due to the single‐ion anisotropy of the CoII ions. [ABSTRACT FROM AUTHOR]

Hexagonal neo-formed crystallites have been observed in thin section of different medieval and post-medieval lead-glazed ceramics. Although they are clearly visible in thin section using plane polarized light, their plate shape makes them barely seen on the polished cross sections. Basal sections have never been found on the polished sections and only few transversal very thin sections could be seen. In this case, the morphology resembles acicular and it is not possible to analyze them properly by SEM-EDX because the crystals are very thin and the glaze surrounding is analyzed as well. Micro-Raman microscopy was carried out directly on the polished thin sections. This technique allows specific areas as small as 1 μm in diameter to be analyzed and it is able to characterize inclusions that are not found on the glaze surface. However, the wavenumber features observed cannot be assigned to a specific compound. The thickness of the crystallites (a few hundred nanometers) seems to be responsible for the low sensitivity of the Raman instrumentation. 15 × 15 μm2 micro-X-ray diffraction patterns using synchrotron radiation (SR-μXRD) in transmission geometry were obtained from the crystals using the same thin section preparation. SR-μXRD was able to localize the crystallites and avoid the overlapping signals corresponding to other mineral phases. In this way, the hexagonal crystallites present in the glaze have been unambiguously identified as hematite crystallites. Finally, some replications were made under laboratory-controlled conditions to determine the firing conditions in the formation of those crystallites. The presence of hematite coexisting with melanotekite indicates a firing temperature <925°C, while the presence of only hematite suggests a firing temperature >925°C [ABSTRACT FROM AUTHOR]

We present the first magnetic phase of an ionic liquid with anion-π interactions, which displays a three-dimensional (3D) magnetic ordering below the Néel temperature, TN = 7.7 K. In this material, called Dimim[FeBr4], an exhaustive and systematic study involving structural and physical characterization (synchrotron X-ray, neutron powder diffraction, direct current and alternating current magnetic susceptibility, magnetization, heat capacity, Raman and Mössbauer measurements) as well as first-principles analysis (density functional theory (DFT) simulation) was performed. The crystal structure, solved by Patterson-function direct methods, reveals a monoclinic phase (P21 symmetry) at room temperature with a = 6.745(3) Å, b = 14.364(3) Å, c = 6.759(3) Å, and β = 90.80(2)°. Its framework, projected along the b direction, is characterized by layers of cations [Dimim]+ and anions [FeBr4]- that change the orientation from layer to layer, with Fe···Fe distances larger than 6.7 Å. Magnetization measurements show the presence of 3D antiferromagnetic ordering below TN with the existence of a noticeable magneto-crystalline anisotropy. From low-temperature neutron diffraction data, it can be observed that the existence of antiferromagnetic order is originated by the antiparallel ordering of ferromagnetic layers of [FeBr4]- metal complex along the b direction. The magnetic unit cell is the same as the chemical one, and the magnetic moments are aligned along the c direction. The DFT calculations reflect the fact that the spin density of the iron ions spreads over the bromine atoms. In addition, the projected density of states (PDOS) of the imidazolium with the bromines of a [FeBr4]- metal complex confirms the existence of the anion-π interaction. Magneto-structural correlations give no evidence for direct iron-iron interactions, corroborating that the 3D magnetic ordering takes place via superexchange coupling, the Fe-Br···Br-Fe interplane interaction being defined as the main exchange pathway. [ABSTRACT FROM AUTHOR]

We report the synthesis, physicochemical characterization, and crystal structure of Cu-SP (SP = styrylphosphonic acid, H2O3PCH=CH2(C6H5)), the first reported example of a metal derivative of SP. The starting SP acid was fully characterized by X-ray single-crystal diffractometry, elemental analysis (C and H),31P-NMR,13C-NMR,1H-NMR, HPLC, UV–vis, MS, TG, and FT-IR spectroscopy. The copper(II) derivative was synthesized and characterized by DTA-TG and FT-IR, and also its structure was determined from powder data. The crystal structure was refined by the Rietveld method. The crystal structure of Cu-SP shows a layered 2-D architecture, where the organic moieties are pointed toward the interlamellar space. The inorganic layers are composed of Cu2+dimers, where the coordination geometry of Cu2+can be described as distorted trigonal bipyramid. The three coplanar oxygens (O2, O3, and O3) have bond distances of 2.165(9), 1.982(9), and 2.103(11) Å, respectively. The bond lengths for the apical oxygens (O1 and O2) are 1.908(13) and 1.996(11) Å, respectively. [ABSTRACT FROM AUTHOR]

In this paper we report the spectral properties of the stable radical adducts 1*-3*, which ate formed by an electron donor moiety, the carbazole ring and an electron acceptor moiety, the polychlorotriphenylmethyl radical. The molecular structure of radical adduct 1* in the crystalline state shows a torsion angle of approximately 90° between the pheny| and the carbazole rings due to steric interactions. They exhibit a charge transfer band in the visible range of the electronic spectrum. All of them are chemically oxidized with copper(II) perchlorate to the respective cation species, which show a strong charge transfer band into the near-infrared region of the spectrum. Radical adducts 1*-3* and the corresponding stable oxidized species 1+-3+ are real organic mixed-valence compounds due to the open-shell nature of their electronic structure. Charge transfer bands of the cation species are stronger and are bathochromically shifted with respect to those of the neutral species due to the greater acceptor ability of the positively charged central carbon atom of the triphenylmethyl moiety. The cationic species 1+-3+ are diamagnetic, as shown by the absence of a signal in the EPR spectrum in acetonitrile solution at room temperature, but they show an intense and unique band in frozen solutions (183 K). [ABSTRACT FROM AUTHOR]

A new three-dimensional hydroxide-arsenate compound called compound 2 has been synthesized by heating (in air) of the sarkinite phase, Mn2(OH)AsO4 (compound 1), with temperature and time control. The crystal structure of this high-temperature compound has been solved by Patterson-function direct methods. A relevant feature of this new material is that it is actually the first member of the adamite-type family with mixed-valence manganese(II,III) and electronic conductivity. Crystal data: a = 6.7367(5) Å, b = 7.5220(6) Å, c = 9.8117(6) Å, α = 92.410(4)°, β = 109.840(4)°, γ = 115.946(4)°, P1. The unit cell content derived from Rietveld refinement is Mn8(O4Hx)(AsO4)4. Its framework, projected along [111], is characterized by rings of eight Mn atoms with the OH-/O2- inside the rings. These rings form an almost perfect hexagonal arrangement with the AsO4 groups placed in between. Bond-valence analysis indicates both partial deprotonation (x⩾ 3) and the presence of Mn in two different oxidation states (II and III), which is consistent with the electronic conductivity above 300 °C from electrochemical measurements. The electron paramagnetic resonance spectra of compound 1 and of its high-temperature form compound 2 show the presence of antiferromagnetic interactions with stronger magnetic coupling for the high-temperature phase. Magnetization measurements of room-temperature compound 1 show a complex magnetic behavior, with a three-dimensional antiferromagnetic ordering and magnetic anomalies at low temperatures, whereas for compound 2, an ordered state is not reached. Magnetostructural correlations indicate that superexchange interactions via oxygen are present in both compounds. The values of the magnetic exchange pathways [Mn-O-Mn] are characteristic of antiferromagnetic couplings. Notwithstanding, the existence of competition between different magnetic interactions through superexchange pathways can cause the complex magnetic behavior of compound 1. The loss of three-dimensional magnetic ordering by heating of compound 1 could well be based on the presence of Mn3+ ions (d4) in compound 2. [ABSTRACT FROM AUTHOR]

Some theoretical and practical aspects of the application of transmission microdiffraction (µXRD) to thin sections (≤30 µm thickness) of samples fixed or deposited on substrates are discussed. The principal characteristic of this technique is that the analysed micro-sized region of the thin section is illuminated through the substrate (tts-µXRD). Fields that can benefit from this are mineralogy, petrology and materials sciences since they often require in situ lateral studies to follow the evolution of crystalline phases or to determine new crystal structures in the case of phase transitions. The capability of tts-µXRD for performing structural studies with synchrotron radiation is shown by two examples. The first example is a test case in which tts-µXRD intensity data of pure aerinite are processed using Patterson-function direct methods to directly solve the crystal structure. In the second example, tts-µXRD is used to study the transformation of laumonite into a new aluminosilicate for which a crystal structure model is proposed. [ABSTRACT FROM AUTHOR]

Archaeometric studies on mosaics often concentrate only on glass tesserae, while comprehensive studies including both stone and glass tesserae are scarce; however, both types of tesserae can sometimes bring relevant data to elaborate archaeological knowledge on a studied mosaic. In this paper, a representative set of tesserae from a large polychrome Roman mosaic retrieved in Barcelona (NE Spain) is investigated using various methods. Most of the techniques were directly applied on samples prepared as petrographic thin sections (including polarized-light, cathodoluminescence and electron microscopies, and synchrotron through-the-substrate μX-ray diffraction). The results indicate that, from the ten sampled stone tesserae, there are (i) seven limestones, one of them identified as Alveolina limestone (early Eocene) from the southern Pyrenees (ii) two sandstones from Barcelona's Montjuïc hill (Miocene) and, (iii) a Carrara white marble from the Apuan Alps (Italy). The profuse presence of tesserae of both local and imported materials with well-known uses in architecture, epigraphy, and sculpture could imply that tesserae were a by-product of their main use. Two different production technologies were identified for the three sampled glass tesserae. The concurrent use of antimony- and tin-based opacifiers is in agreement with the accepted archaeological chronology of the mosaic (4th century AD). [ABSTRACT FROM AUTHOR]

A new imidazolium-based halometallate complex with formula (trimim)[FeBr 4 (trimim: 1,2,3-trimethylimidazolium) has been synthesized and characterized as a function of the temperature. The structural phase transitions, magnetic properties and magnetic structure of this compound have been thoroughly studied. The crystal structure evolution from 1.8 to 400 K has been investigated by a combination of synchrotron X-ray and neutron powder diffraction, as well as single crystal X-ray and neutron diffraction. Four different phases were found: phase I , from 400 to 350 K, with the orthorhombic Cmc 2 1 space group; phase II , from 350 to 160 K, which was modelled with the monoclinic P 2 1 / m space group; and phase III , stable down to 13 K and showing the monoclinic Cm space group. The transition from phase III to II involves the appearance of disorder in the organic cations. Magnetometry measurements indicate a long-range magnetic order below 13 K, which was confirmed by single crystal and powder neutron X-ray diffraction analyses. The occurrence of new reflections that were not possible to index with the phase III unit cell suggests a symmetry breaking, giving rise to the phase IV. A joint refinement (single-crystal and powder data) revealed that the latter phase exhibits the magnetic Shubnikov C c c space group. This model consists of a strictly antiferromagnetic structure with ferromagnetic interactions within the unit cell, which is compatible with the magnetometry results. Synopsis: Scheme of the different phase transitions of (trimim)[FeBr 4. [Display omitted] • A new imidazolium-based halometallate complex was synthetized and characterized. • The complex displays the highest melting point of its family. • The crystal structure evolution from 1.8 to 400 K shows four different phases. • The complex displays an antiferromagnetic structure with ferromagnetic interactions. • A comparative analysis is shown with the tetrachloroferrate analogue, trimim(FeCl 4) [ABSTRACT FROM AUTHOR]

Eighteen samples of the (dimim)[Fe(Cl 1−x Br x) 4 ] 0 ≤ x ≤ 1 solid solution were prepared in a one-pot synthesis. Single crystal and synchrotron X-ray powder diffraction studies show that all compounds are isomorphous with an orthorhombic structure (Ama 2 space group) at room temperature. The crystal structure of these imidazolium molten salts can be described as layers of (dimim)+ cations (dimim = 1,3-dimethyl-imidazolium) extended in the bc -plane with an antiparallel stacking along the a -axis forming a herring-bond motive. The (FeX 4)− (X = Cl and Br) anions form layers extended on the bc -plane that are intercalated between the organic layers and inverted with respect to the adjacent layer along the a direction. The evolution of the cell volume at this temperature follows the Vegard's law in the whole range of substitution with ∆V ≈ 115 Å3 between non-substituted phases, showing a non-linear axial expansion in the b and c directions. In addition, the melting point of the solid solution does not follow the expected linear physical behavior. Finally, the magnetic study indicates the existence of overall antiferromagnetic interactions as predominant, which are stronger with the increase in the (FeBr 4)− ion substitution. However, it was found that the 3D magnetic ordering of the non-substituted phases vanishes or it is below the minimum temperature reachable by the magnetometer devices (1.8 K) for the 25–50% bromide substitutions. This is connected with the appearance of different crystal phases as function of bromide composition at low temperature. Unlabelled Image • A halometallate solid solution of eighteen samples were synthetized characterized. • All compounds are isomorphous with an orthorhombic structure at room temperature. • All structural parameters except to c- and b -axis show a linear expansion • The melting point and magnetic properties do not show the expected linear behavior. • The 3D magnetic ordering vanishes for a 25-50% bromide substitution. [ABSTRACT FROM AUTHOR]

The study of the alteration process, and in particular of secondary phases precipitated in pottery after its production, can constrain the post-depositional environments or the type of use of the pottery. Detailed study of secondary phases can be done using different approaches, based on microscopic, microstructural and microchemical analyses, as well as mineralogical methods. In the present study are reported the results of the application of punctual mineralogical analysis by synchrotron through-the-substrate microdiffraction (tts-μXRD) to analyse secondary phases precipitated in ancient pottery (Bronze Age pottery form Frattesina in Italy and Mesolithic pottery form Al Khiday in Sudan). Although the chemical composition of these secondary phases in many cases almost matches with the stoichiometric composition of a known mineral, only some of them were actually true mineral phases (i.e. with crystallinity and therefore showing diffraction peaks), while others were amorphous. Some phases, the occurrence of which was previously attested only on the basis of their chemical composition (determined by scanning electron microscope or the electron microprobe analysis), were univocally identified as true vivianite (Fe3(PO4)2·8H2O) and crandallite (CaAl3(PO4)2(OH)5·H2O) minerals. Part of the phases detected in studied pottery, the chemical composition of which was consistent with specific mineral phases, were instead amorphous. The synchrotron through-the-substrate microdiffraction (tts-μXRD), therefore, represents a valid method for properly determine the mineralogical nature of secondary phases in pottery, as well as other small-sized and rare mineral phases occurring in polycrystalline materials of archaeological interest, such as pottery, mortars, painting and glassy materials. [ABSTRACT FROM AUTHOR]

The archaeometric study of the “golden slip” ware (second century BCE—fourth century CE) at the site of Barikot (Swat, north-western Pakistan) aimed to define its manufacturing technology and provenance of the raw materials used. For this reason, a multianalytical approach consisting of the microscopic, microstructural and mineralogical analysis of both the golden slip and the ceramic paste was adopted. The slip was found to be composed by platy minerals, microchemically identified as talc and chlorite; their intimate association indicated clearly that they derived from a chlorite-talc schist. This rock is geologically available near the site in the “green stones” lenses within the Mingora ophiolites outcropping in the Swat valley. Due to the use of this stone also for the production of stone tools, it cannot be excluded that the chlorite-talc schist used for the golden slip can be derived from manufacturing residues of the Gandharan sculptures. In order to constrain the firing production technology, laboratory replicas were produced using a locally collected clay and coating them with ground chlorite-talc schist. On the basis of the mineralogical association observed in both the slip and the ceramic paste and the thermodynamic stability of the pristine mineral phases, the golden slip pottery underwent firing under oxidising conditions in the temperature interval between 800 °C and 850 °C. The golden and shining looks of the slip were here interpreted as the result of the combined light reflectance of the platy structure of the talc-based coating and the uniform, bright red colour of the oxidized ceramic background. [ABSTRACT FROM AUTHOR]

The ware called Taches Noires was developed in Albisola (Liguria, NW Italy) during the 18th century. In just a few years, it spread all over the Mediterranean (Italy, France, Spain, Tunisia, and Greece) and also in the New World (Canada, the Caribbean Islands, and Mexico). The success of the Taches Noires ware was so massive that it was soon copied by Spanish and French workshops. A collection of Catalan imitations and Ligurian imports found in Barcelona were analysed and compared to previously existing data from Barcelona productions, as well as reference samples from Albisola. The study proved the presence of both local imitations and original Albisola imports. The analysis showed a homogeneous product of high technical quality for the Albisola pottery. On the contrary, the local imitations presented a greater diversification in the choice and manipulation of the raw materials, probably related to the existence of different workshops engaged in the manufacturing of these products. Nevertheless, for one of the local groups, ceramists adopted a glaze recipe similar to the one used in Albisola, clearly indicating a direct transfer of knowledge, and possibly of potters, from Albisola to Barcelona. [ABSTRACT FROM AUTHOR]

The new three-dimensional compound Mn8(O4Hx)(AsO4)4 (x ≈ 3) is prepared by heating Mn2(OH)AsO4 in air at 500 °C. [ABSTRACT FROM AUTHOR]