There is a special reason for reviewing this book at this time: it is the 50th edition of a compendium that is known and used frequently in most chemical and physical laboratories in many parts of the world. Surely, a publication that has been published for 56 years, withstanding the vagaries of science in this century, must have had something to offer. There is another reason: while the book is a standard fixture in most chemical and physical laboratories, including those in medical centers, it is not as frequently seen in the laboratories of physician's offices (those either in solo or group practice). I believe that the Handbook can be useful in those laboratories. One of the reasons, among others, is that the various basic items of information it offers may be helpful in new tests, either physical or chemical, which are continuously being published. The basic information may relate

Handbook of Chemistry and Physics

We report the first high-pressure single-crystal structures of hybrid perovskites. The crystalline semiconductors (MA)PbX3 (MA = CH3NH3+, X = Br– or I–) afford us the rare opportunity of understanding how compression modulates their structures and thereby their optoelectronic properties. Using atomic coordinates obtained from high-pressure single-crystal X-ray diffraction we track the perovskites’ precise structural evolution upon compression. These structural changes correlate well with pressure-dependent single-crystal photoluminescence (PL) spectra and high-pressure bandgaps derived from density functional theory. We further observe dramatic piezochromism where the solids become lighter in color and then transition to opaque black with compression. Indeed, electronic conductivity measurements of (MA)PbI3 obtained within a diamond-anvil cell show that the material’s resistivity decreases by 3 orders of magnitude between 0 and 51 GPa. The activation energy for conduction at 51 GPa is only 13.2(3) meV, su...

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High-Pressure Single-Crystal Structures of 3D Lead-Halide Hybrid Perovskites and Pressure Effects on their Electronic and Optical Properties

The liquidus relations in the system YO1.5–BaO–CuOx in air in the compositional region near the superconducting oxide YBa2Cu3Ox were studied by differential thermal analysis, x-ray diffraction, electron microprobe analysis, and visual observation. The temperatures of 11 invariant points and the corresponding reactions were determined. YBa2Cu3Ox was found to melt incogruently at 1015 °C to Y2BaCuO5, which in turn melts incongruently to Y2O3 at 1270 °C. These reactions mean that preparing the superconducting phase by melting and rapid cooling will result in the presence of these two phases as well. The peritectic reaction YBa2Cu3Ox + CuO⇉Y2BaCuO5 + liquid at 940 °C accounts for the observation of partial melting, improved synthesis purity, and grain growth at temperatures of 950 °C. The determination of these invariant temperatures and reactions provide insight into optimal processing conditions.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0884291400003769

Liquidus relations in Y–Ba–Cu oxides

Self-assembled peptide nanostructures have been increasingly exploited as functional materials for applications in biomedicine and energy. The emergent properties of these nanomaterials determine the applications for which they can be exploited. It has recently been appreciated that nanomaterials composed of multicomponent coassembled peptides often display unique emergent properties that have the potential to dramatically expand the functional utility of peptide-based materials. This review presents recent efforts in the development of multicomponent peptide assemblies. The discussion includes multicomponent assemblies derived from short low molecular weight peptides, peptide amphiphiles, coiled coil peptides, collagen, and β-sheet peptides. The design, structure, emergent properties, and applications for these multicomponent assemblies are presented in order to illustrate the potential of these formulations as sophisticated next-generation bio-inspired materials.

/pdf/multicomponent-peptide-assemblies-1mxig4zs64.pdf

Multicomponent peptide assemblies

High throughput (combinatorial) materials science methodology is a relatively new research paradigm that offers the promise of rapid and efficient materials screening, optimization, and discovery. The paradigm started in the pharmaceutical industry but was rapidly adopted to accelerate materials research in a wide variety of areas. High throughput experiments are characterized by synthesis of a “library” sample that contains the materials variation of interest (typically composition), and rapid and localized measurement schemes that result in massive data sets. Because the data are collected at the same time on the same “library” sample, they can be highly uniform with respect to fixed processing parameters. This article critically reviews the literature pertaining to applications of combinatorial materials science for electronic, magnetic, optical, and energy-related materials. It is expected that high throughput methodologies will facilitate commercialization of novel materials for these critically important applications. Despite the overwhelming evidence presented in this paper that high throughput studies can effectively inform commercial practice, in our perception, it remains an underutilized research and development tool. Part of this perception may be due to the inaccessibility of proprietary industrial research and development practices, but clearly the initial cost and availability of high throughput laboratory equipment plays a role. Combinatorial materials science has traditionally been focused on materials discovery, screening, and optimization to combat the extremely high cost and long development times for new materials and their introduction into commerce. Going forward, combinatorial materials science will also be driven by other needs such as materials substitution and experimental verification of materials properties predicted by modeling and simulation, which have recently received much attention with the advent of the Materials Genome Initiative. Thus, the challenge for combinatorial methodology will be the effective coupling of synthesis, characterization and theory, and the ability to rapidly manage large amounts of data in a variety of formats.

/pdf/applications-of-high-throughput-combinatorial-methodologies-2h3ujt1mep.pdf

Applications of high throughput (combinatorial) methodologies to electronic, magnetic, optical, and energy-related materials

Point defects, impurities, and defect-impurity complexes in diamond particles and polycrystalline films were investigated by cathodoluminescence (CL) imaging and spectroscopy in a scanning electron microscope. The diamond films and particles were grown by hot-filament methane-hydrogen chemical-vapor deposition at several different temperatures; the nominal deposition temperature (${T}_{d}$) ranged from 600 to 850 \ifmmode^\circ\else\textdegree\fi{}C. Electron-beam energies used to excite the CL were 10--30 keV. By comparing the CL spectra to spectra of known defects in natural and synthetic diamond, the following luminescence centers were identified: (a) 2.156-eV center (zero-phonon line observed at 2.15\ifmmode\pm\else\textpm\fi{}0.01 eV) attributed to a nitrogen-vacancy complex; (b) 2.326-eV center (observed peak position at 2.32\ifmmode\pm\else\textpm\fi{}0.01 eV), also thought to be a nitrogen-vacancy complex; (c) violet-emitting center (observed peak position at 2.82\ifmmode\pm\else\textpm\fi{}0.01 eV), associated with dislocation line defects, whose atomic structure is uncertain; (d) 3.188-eV center (observed peak position at 3.189\ifmmode\pm\else\textpm\fi{}0.001 eV), attributed to interstitial nitrogen or a nitrogen--(carbon-interstitial) complex; (e) isolated neutral vacancy (denoted the general radiation center) with principal zero-phonon line at 1.673 eV (observed peak position at 1.675\ifmmode\pm\else\textpm\fi{}0.002 eV).The luminescence from each center displayed a different dependence on ${T}_{d}$ and film morphology, as follows: (a) 2.156-eV center, maximum at ${T}_{d}$=600 \ifmmode^\circ\else\textdegree\fi{}C, corresponding to a cubic crystal-growth habit; (b) 2.326-eV center, similar to (a); (c) 2.82-eV center, maximum at ${T}_{d}$=750 \ifmmode^\circ\else\textdegree\fi{}C, octahedral crystal-growth habit; (d) 3.188-eV center, maximum at 650 \ifmmode^\circ\else\textdegree\fi{}C, transition between cubic and octahedral crystal growth; (e) 1.673-eV center (neutral vacancy), observed only at 850 \ifmmode^\circ\else\textdegree\fi{}C, relatively indistinct crystal-growth habit. CL from center (d) was induced by extended exposure to the electron beam. CL imaging of large (\ensuremath{\sim}10-\ensuremath{\mu}m) crystalline particles suggests that centers (a) and (c) are located primarily near {100} faces; the dislocation-related center (c) appears to be slightly more confined to near-surface regions than center (a).

Cathodoluminescence of defects in diamond films and particles grown by hot-filament chemical-vapor deposition.

Porphyrinic compounds comprise a diverse group of materials which have in common the presence of one or more cyclic tetrapyrroles known as porphyrins in their molecular structures. The resulting aromaticity gives rise to the semiconducting properties that make these compounds of interest for a broad range of applications, including artificial photosynthesis, catalysis, molecular electronics, sensors, non-linear optics, and solar cells. In this brief review, the crystallographic attributes of porphyrins are emphasized. Examples are given showing how the structural orientations of the porphyrin macrocycle, and the inter-porphyrin covalent bonding present in multiporphyrins influence the semiconducting properties. Beginning with porphine, the simplest porphyrin, we discuss how the more complex structures that have been reported are described by adding peripheral substituents and internal metalation to the macrocycles. We illustrate how the conjugation of the π-bonding, and the presence of electron donor/acceptor pairs, which are the basis for the semiconducting properties, are affected by the crystallographic topology.

https://www.mdpi.com/2073-4352/7/7/223/pdf

Structural Aspects of Porphyrins for Functional Materials Applications

Crystal chemistry and subsolidus phase equilibrium studies of the Ba-Nd-Cu-O system near the CuO and Nd2O3 corners have been carried cut at 950°C in air. Two solid-solution series have been identified in the Ba-Nd-Cu-O system. The first series involves the high-Tc superconductor phase, and has the formula Ba2–xNd1+xCu3O6+z, where × < ≅ 0.7. At the ideal compound stoichiometry of Ba2NdCu3O6+z, the transformation from the high-Tc orthorhombic to tetragonal phase occurs at 550°–575°C in air. This temperature varies as a function of composition, and at x≅ 0.2 to 0.3 it occurs at 950°C. The second solid solution is the non-superconducting “brown phase” represented by Ba2+2x-Nd4–2xCu2–xO10–2z 0 ≤x≤ 0.1. Preliminary phase diagrams of the BaO–Nd2O3 and Nd2O3–CuOx systems are also presented. Standard X-ray diffraction patterns of BaNd2–CuO5 and (Nd1.9Ca0.1)CuO4–z are provided.

Crystal Chemistry and Phase Equilibrium Studies of the BaO(BaCO3)–½R2O3–CuOx Systems in Air: VI, R = Neodymium

Since the discovery of high-temperature superconductivity in the Bi-Sr-Ca-Cu-O (BSCCO) system, substantial research efforts have been expended in the areas of phase equilibria, processing, characterization, physical property measurement, and practical applications of these materials. This paper reports that one advantage of BSCCO materials, as compared to Ba-Y-Cu-O (BYCO) ceramics, is the presence of phases exhibiting superconducting properties at 80 and 110 K. The principal attribute of BSCCO, however, is the apparent absence of weak-link behavior in this material, a problem which can severely limit critical currents in bulk BYCO. The BSCCO system also offers the opportunity of glass formation so that glass-ceramic processing techniques can be used to form and crystallize materials into the desired products. An interesting problem exists with respect to forming the 110 K (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} (2223) phase in the BSCCO system. Efforts to obtain this 2223 phase directly from the lead-free Bi-Sr-Ca-Cu-O system have been largely unsuccessful, although reports have been made to the contrary. The addition of Pb to the starting materials has been found necessary to achieve significant quantities of 2223.

Phase formation of high-T sub c superconducting oxides in the Bi-Pb-Sr-Ca-Cu-O glass

Eutectic melting in the BaO-[1/2]Y[sub 2]O[sub 3]-CuO[sub x] system has been investigated, using three different compositions. Thermal events up to 1,100 C were studied by means of differential thermal analysis/thermogravimetric analysis (DTA/TGA). Phase formation and compositions of melts were examined using powder X-ray diffraction and scanning electron microscopy/energy-dispersive X-ray spectrometry (SEM/EDS) of quenched experiments. The eutectic occurs at 923 [+-] 10 C in CO[sub 2]-, and H[sub 2]O-scrubbed air, and the eutectic melt has a Ba:Y:Cu cation ratio of 23.2([+-]0.5):0.5([+-]0.1):76.3(1.0). The oxygen content of the quenched eutectic melt, as determined by hydrogen reduction, indicated that nearly all of the copper in the melt was present as Cu[sup +]. A topological sequence, based on the X-ray results, is presented which describes the events immediately following melting.

Lawrence P. Cook

Papers

Cathodoluminescence of defects in diamond films and particles grown by hot-filament chemical-vapor deposition.

Structural Aspects of Porphyrins for Functional Materials Applications

Crystal Chemistry and Phase Equilibrium Studies of the BaO(BaCO3)–½R2O3–CuOx Systems in Air: VI, R = Neodymium

Phase formation of high-T sub c superconducting oxides in the Bi-Pb-Sr-Ca-Cu-O glass

BaO–1/2Y2O3–CuOx Eutectic Melting in Air