Binary chalcogen halogen EX4 species represent intriguing systems in terms of chemical bonding theories, such as hypervalency and stereoactivity of lone electron pairs. Instead of a simple molecular EX4 structure, selenium tetrachloride forms an ionic pair, Cl3Se+Cl−, that assembles into a tetrameric (SeCl4)4 structure, namely, tetra-μ3-chlorido-dodecachloridotetraselenium. This article describes the charge–density analysis of the tetrameric molecule of β-SeCl4 based on the aspherical model obtained from Hirshfeld Atom Refinement of the tetrameric molecule and of an explicit cluster of 15 tetramers that simulates the crystal packing. Deformation density, electron localization function (ELF) and Quantum Theory of Atoms in Molecules (QTAIM) were used to evaluate the bonding situation, the electron-density distribution around the Se atom and the interaction energy of the tetramer.

With the exception of SF6-to-air bushings terminals, all active portions of gas-insulated switchgear (GIS) are contained within grounded enclosures, which means that they are not susceptible to inadvertent contact. This makes gas-insulated switchgear intrinsically safe. In addition, numerous grounding procedures... Read more

The post Practical lesson in grounding and bonding of Gas-Insulated Switchgear (GIS) appeared first on EEP - Electrical Engineering Portal.

Acucote, a solutions-oriented pressure-sensitive adhesive coating manufacturer, has introduced WOff, a Wash Off Adhesive, a water-based formula that provides debonding of non-recyclable label materials from PET and glass containers, making them recoverable. 

Natural Bonds is not only a home for animals, however: It is also a home for people. 

Cleaning up after class turns into a moment of sharing between an OM worker and two North African women.

Michael Jackson’s pal Donny Osmond shares reason of their close bonding Michael Jackson and Donny Osmond had quite a similar family background. The Puppy Love crooner made an appearance in MTV Entertainment Studios documentary Larger than Life: Reign of the Boybands, where...

Abingdon, Oxon ; New York, NY : Routledge, 2021.

Teachers need to master two secrets to be successful in their careers.

To Paul Mathew, theatre is an effective management tool that can promote holistic thinking

Catalyst spurs insoluble salts into action as nucleophiles for enantioselective reactions

According to Arpita Mandal, the City of Joy, now that she’s two decades older, is today less suitable for pandal-hopping, due to the massive crowds, and more suitable for cafe-hopping, with plenty of eateries mushrooming even in residential neighbourhoods

From solutions of prehnitene and the ternary halides (SnCl)[MCl4] (M = Al, Ga) in chloro­benzene, the new cationic SnII–π-arene complexes catena-poly[[chlorido­aluminate(III)]-tri-μ-chlorido-4':1κ2Cl,1:2κ4Cl-[(η6-1,2,3,4-tetra­meth­yl­benzene)­tin(II)]-di-μ-chlorido-2:3κ4Cl-[(η6-1,2,3,4-tetra­methyl­benzene)­tin(II)]-di-μ-chlorido-3:4κ4Cl-[chlorido­aluminate(III)]-μ-chlorido-4:1'κ2Cl], [Al2Sn2Cl10(C10H14)2]n, (1) and catena-poly[[chlorido­gallate(III)]-tri-μ-chlor­ido-4':1κ2Cl,1:2κ4Cl-[(η6-1,2,3,4-tetra­methyl­benzene)­tin(II)]-di-μ-chlorido-2:3κ4Cl-[(η6-1,2,3,4-tetra­methyl­benzene)­tin(II)]-di-μ-chlorido-3:4κ4Cl-[chlor­ido­gallate(III)]-μ-chlorido-4:1'κ2Cl], [Ga2Sn2Cl10(C10H14)2]n, (2), were isolated. In these first main-group metal–prehnitene complexes, the distorted η6 arene π-bonding to the tin atoms of the Sn2Cl22+ moieties in the centre of [{1,2,3,4-(CH3)4C6H2}2Sn2Cl2][MCl4]2 repeating units (site symmetry overline{1}) is characterized by: (i) a significant ring slippage of ca 0.4 Å indicated by the dispersion of Sn—C distances [1: 2.881 (2)–3.216 (2) Å; 2: 2.891 (3)–3.214 (3) Å]; (ii) the non-methyl-substituted arene C atoms positioned closest to the SnII central atom; (iii) a pronounced tilt of the plane of the arene ligand against the plane of the central (Sn2Cl2)2+ four-membered ring species [1: 15.59 (11)°, 2: 15.69 (9)°]; (iv) metal–arene bonding of medium strength as illustrated by application of the bond-valence method in an indirect manner, defining the π-arene bonding inter­action of the SnII central atoms as s(SnII—arene) = 2 − Σs(SnII—Cl), that gives s(SnII—arene) = 0.37 and 0.38 valence units for the aluminate and the gallate, respectively, indicating that comparatively strong main-group metal–arene bonding is present and in line with the expectation that [AlCl4]− is the slightly weaker coordinating anion as compared to [GaCl4]−.

In the crystal structure of the isostructural title compounds, namely {2,6-bis­[(di-tert-butyl­phosphan­yl)­oxy]-4-hy­droxy­phen­yl}chlorido­palladium(II), [Pd(C22H39O3P2)Cl], 1, and {2,6-bis­[(di-tert-butyl­phosphan­yl)­oxy]-4-hy­droxy­phen­yl}chlorido­platinum(II), [Pt(C22H39O3P2)Cl], 2, the metal centres are coordinated in a distorted square-planar fashion by the POCOP pincer fragment and the chloride ligand. Both complexes form strong hydrogen-bonded chain structures through an inter­action of the OH group in the 4-position of the aromatic POCOP backbone with the halide ligand.

The title compound, C12H21NO7, (I), is conformationally unstable; the predominant form present in its solution is the β-pyran­ose form (74.3%), followed by the β- and α-furan­oses (12.1 and 10.2%, respectively), α-pyran­ose (3.4%), and traces of the acyclic carbohydrate tautomer. In the crystalline state, the carbohydrate part of (I) adopts the 2C5 β-pyran­ose conformation, and the amino acid portion exists as a zwitterion, with the side chain cyclo­pentane ring assuming the E9 envelope conformation. All heteroatoms are involved in hydrogen bonding that forms a system of anti­parallel infinite chains of fused R33(6) and R33(8) rings. The mol­ecule features extensive intra­molecular hydrogen bonding, which is uniquely multicentered and involves the carboxyl­ate, ammonium and carbohydrate hy­droxy groups. In contrast, the contribution of inter­molecular O⋯H/H⋯O contacts to the Hirshfeld surface is relatively low (38.4%), as compared to structures of other d-fructose-amino acids. The 1H NMR data suggest a slow rotation around the C1—C2 bond in (I), indicating that the intra­molecular heteroatom contacts survive in aqueous solution of the mol­ecule as well.

Charge-assisted hydrogen bonding plays a significant role in the crystal structures of solvates of ionic com­pounds, especially when the cation or cations are primary ammonium salts. We report the crystal structures of four ammonium salts of molybdenum halide cluster solvates where we observe significant hydrogen bonding between the solvent molecules and cations. The crystal structures of bis­(anilinium) octa-μ3-chlorido-hexa­chlorido-octa­hedro-hexa­molybdate N,N-di­­methyl­formamide tetra­solvate, (C6H8N)2[Mo6Cl8Cl6]·4C3H7NO, (I), p-phenyl­enedi­ammonium octa-μ3-chlorido-hexa­chlorido-octa­hedro-hexa­mol­yb­date N,N-di­methyl­formamide hexa­solvate, (C6H10N2)[Mo6Cl8Cl6]·6C3H7NO, (II), N,N'-(1,4-phenyl­ene)bis­(propan-2-iminium) octa-μ3-chlorido-hexa­chlo­rido-octa­hedro-hexa­molybdate acetone tris­olvate, (C12H18N2)[Mo6Cl8Cl6]·3C3H6O, (III), and 1,1'-dimethyl-4,4'-bipyridinium octa-μ3-chlo­rido-hexa­chlorido-octa­hedro-hexa­molybdate N,N-di­methyl­formamide tetra­solvate, (C12H14N2)[Mo6Cl8Cl6]·4C3H7NO, (IV), are reported and described. In (I), the anilinium cations and N,N-di­methyl­formamide (DMF) solvent mol­ecules form a cyclic R42(8) hydrogen-bonded motif centered on a crystallographic inversion center with an additional DMF mol­ecule forming a D(2) inter­action. The p-phenyl­enedi­ammonium cation in (II) forms three D(2) inter­actions between the three N—H bonds and three independent N,N-di­methyl­formamide mol­ecules. The dication in (III) is a protonated Schiff base solvated by acetone mol­ecules. Compound (IV) contains a methyl viologen dication with N,N-di­methyl­formamide mol­ecules forming close contacts with both aromatic and methyl H atoms.

The redetermined structure [for the previous study, see: Godfrey & Waters (1975). Cryst. Struct. Commun. 4, 5–8] of ammonium μ-oxido-μ-[1,5,6-tri­hydroxy­hexane-2,3,4-tris­(olato)]bis­[dioxidomolybdenum(V)] monohydrate, NH4[Mo2(C6H11O6)O5]·H2O, was obtained from an attempt to prepare a glutamic acid complex from the [Co2Mo10H4O38]6− anion. Subsequent study indicated the complex arose from a substantial impurity of mannitol in the glutamic acid sample used. All hydrogen atoms have been located in the present study and the packing displays N—H⋯O, O—H⋯O and C—H⋯O hydrogen bonds. A Hirshfeld surface analysis was also performed.

The crystal structures of two salt crystals of 2,2-bis­(4-methyl­phen­yl)hexa­fluoro­propane (Bmphfp) with amines, namely, dipyridinium 4,4'-(1,1,1,3,3,3-hexa­fluoro­propane-2,2-di­yl)dibenzoate 4,4'-(1,1,1,3,3,3-hexa­fluoro­propane-2,2-di­yl)di­benzoic acid, 2C5H6N+·C17H8F6O42−·C17H10F6O4, (1), and a monohydrated ethyl­enedi­ammonium salt ethane-1,2-diaminium 4,4'-(1,1,1,3,3,3-hexa­fluoro­propane-2,2-di­yl)dibenzoate monohydrate, C2H10N22+·C17H8F6O42−·H2O, (2), are reported. Compounds 1 and 2 crystallize, respectively, in space group P21/c with Z' = 2 and in space group Pbca with Z' = 1. The crystals of compound 1 contain neutral and anionic Bmphfp mol­ecules, and form a one-dimensional hydrogen-bonded chain motif. The crystals of compound 2 contain anionic Bmphfp mol­ecules, which form a complex three-dimensional hydrogen-bonded network with the ethyl­enedi­amine and water mol­ecules.

A large amount of hydrogen circulates inside the Earth, which affects the long-term evolution of the planet. The majority of this hydrogen is stored in deep Earth within the crystal structures of dense minerals that are thermodynamically stable at high pressures and temperatures. To understand the reason for their stability under such extreme conditions, the chemical bonding geometry and cation exchange mechanism for including hydrogen were analyzed in a representative structure of such minerals (i.e. phase E of dense hydrous magnesium silicate) by using time-of-flight single-crystal neutron Laue diffraction. Phase E has a layered structure belonging to the space group R3m and a very large hydrogen capacity (up to 18% H2O weight fraction). It is stable at pressures of 13–18 GPa and temperatures of up to at least 1573 K. Deuterated high-quality crystals with the chemical formula Mg2.28Si1.32D2.15O6 were synthesized under the relevant high-pressure and high-temperature conditions. The nuclear density distribution obtained by neutron diffraction indicated that the O—D dipoles were directed towards neighboring O2− ions to form strong interlayer hydrogen bonds. This bonding plays a crucial role in stabilizing hydrogen within the mineral structure under such high-pressure and high-temperature conditions. It is considered that cation exchange occurs among Mg2+, D+ and Si4+ within this structure, making the hydrogen capacity flexible.

While studying the social dynamics of the bearded saki, a primate living in the rainforests of Suriname, primatologist Tremaine Gregory of the Smithsonian Conservation Biology […]

The post Study: Male bonding brings peace, lets primates live in big groups appeared first on Smithsonian Insider.

The crystal structure of tri­phenyl­methanol, C19H16O, has been redetermined using data collected at 295 and 153 K, and is compared to the model published by Ferguson et al. over 25 years ago [Ferguson et al. (1992). Acta Cryst. C48, 1272–1275] and that published by Serrano-González et al., using neutron and X-ray diffraction data [Serrano-González et al. (1999). J. Phys. Chem. B, 103, 6215–6223]. As predicted by these authors, the hy­droxy groups are involved in weak inter­molecular hydrogen bonds in the crystal, forming tetra­hedral tetra­­mers based on the two independent mol­ecules in the asymmetric unit, one of which is placed on the threefold symmetry axis of the Roverline{3} space group. However, the reliable determination of the hy­droxy H-atom positions is difficult to achieve, for two reasons. Firstly, a positional disorder affects the full asymmetric unit, which is split over two sets of positions, with occupancy factors of ca 0.74 and 0.26. Secondly, all hy­droxy H atoms are further disordered, either by symmetry, or through a positional disorder in the case of parts placed in general positions. We show that the correct description of the hydrogen-bonding scheme is possible only if diffraction data are collected at low temperature. The pro­chiral character of the hydrogen-bonded tetra­meric supra­molecular clusters leads to enanti­omorphic three-dimensional graphs in each tetra­mer. The crystal is thus a racemic mixture of supS and supR motifs, consistent with the centro­symmetric nature of the Roverline{3} space group.

Crystals of the rare earth metal polytelluride LaTe1.82(1), namely, lanthanum telluride (1/1.8), have been grown by molten alkali halide flux reactions and vapour-assisted crystallization with iodine. The two-dimensionally incommensurately modulated crystal structure has been investigated by X-ray diffraction experiments. In contrast to the tetra­gonal average structure with unit-cell dimensions of a = 4.4996 (5) and c = 9.179 (1) Å at 296 (1) K, which was solved and refined in the space group P4/nmm (No. 129), the satellite reflections are not compatible with a tetra­gonal symmetry but enforce a symmetry reduction. Possible space groups have been derived by group–subgroup relationships and by consideration of previous reports on similar rare earth metal polychalcogenide structures. Two structural models in the ortho­rhom­bic superspace group, i.e. Pmmn(α,β,1 over 2)000(−α,β,1 over 2)000 (No. 59.2.51.39) and Pm21n(α,β,1 over 2)000(−α,β,1 over 2)000 (No. 31.2.51.35), with modulation wave vectors q1 = αa* + βb* + 1 over 2c* and q2 = −αa* + βb* + 1 over 2c* [α = 0.272 (1) and β = 0.314 (1)], have been established and evaluated against each other. The modulation describes the distribution of defects in the planar [Te] layer, coupled to a displacive modulation due to the formation of different Te anions. The bonding situation in the planar [Te] layer and the different Te anion species have been investigated by density functional theory (DFT) methods and an electron localizability indicator (ELI-D)-based bonding analysis on three different approximants. The temperature-dependent electrical resistance revealed a semiconducting behaviour with an estimated band gap of 0.17 eV.

A separation membrane according to the present invention is characterized by having a porous tube containing an alumina as a main component and an attachment member disposed in a connection position of the porous tube, wherein the porous tube and the attachment member are bonded by a ceramic oxide-based bonding agent containing 17 to 48 wt % of SiO2, 2 to 8 wt % of Al2O3, 24 to 60 wt % of BaO, and 0.5 to 5 wt % of ZnO as essential components and containing at least one of La2O3, CaO, and SrO, and a thin zeolite layer is formed on a surface of the porous tube. The attachment member is bonded to the porous tube before the formation of the zeolite layer. Therefore, the bonding agent can have a melting temperature higher than 600° C., which is the upper heatproof temperature limit of the zeolite. Thus, the ceramic oxide material for the bonding agent can be selected from a wider range of compositions such as glass compositions (without limitations on the glass softening temperature).

A polymerizable composition includes at least one monomer, a photoinitiator capable of initiating polymerization of the monomer when exposed to light, and a phosphor capable of producing light when exposed to radiation (typically X-rays). The material is particularly suitable for bonding components at ambient temperature in situations where the bond joint is not accessible to an external light source. An associated method includes: placing a polymerizable adhesive composition, including a photoinitiator and energy converting material, such as a down-converting phosphor, in contact with at least two components to be bonded to form an assembly; and, irradiating the assembly with radiation at a first wavelength, capable of conversion (down-conversion by the phosphor) to a second wavelength capable of activating the photoinitiator, to prepare items such as inkjet cartridges, wafer-to-wafer assemblies, semiconductors, integrated circuits, and the like.

The present disclosure generally relates to a HAMR head and a method for fabrication thereof. The HAMR head has a write head with a waveguide extending therethrough. A laser diode is coupled to a submount that is bonded to the write head using an adhesion layer, a solder structure, and a self-propagating multilayer alloying stack.

The bonding apparatus is capable of effectively increasing temperature of a substrate and reducing occurrence of position gaps and poor connection in a process of flip-chip-bonding semiconductor devices to the substrate. The bonding apparatus comprises: a supporting unit for supporting the substrate, on which the semiconductor devices have been adhered by a non-conductive; and a heating/pressing unit for heating and pressing the substrate, the heating/pressing unit having a built-in heat source and a clamping face, onto which the substrate supported by the supporting unit is pressed. The substrate supported by the supporting unit is moved toward the clamping face of the heating/pressing unit so as to preheat the substrate and the semiconductor devices by radiation heat. Then, the semiconductor devices are pressed onto the clamping face of the heating/pressing unit so as to cure the non-conductive adhesive and bond bumps of the semiconductor devices to terminal sections of the substrate.

A support structure for supporting a semiconductor device during a bonding operation is provided. The support structure comprises a body portion defining an upper surface configured to support a semiconductor device during a bonding operation. The upper surface defines a constraining feature for constraining at least a portion of the semiconductor device during the bonding operation.