When the exciton densities are below the Mott threshold for the condensation into electron-hold liquid, the excitons are well described by the Wannier Mott model of Coulomb-bound electron–hole pairs. The dielectric response of the materials will be influenced by the presence of these excitons. ...
Albeit halogen bonds in these complexes are somewhat weaker than those in the systems of bare anions, these interactions still belong to strong halogen bonds and show some covalent character. The strength of these interactions deceases in the following order: [Cl]≈[Br]≈[I]>[Ac]≈[NO3]>[...
halogen bonded pairs. In light of this result, we contend that halogen bonding is better described by analogy to metal coordination bonds rather than hydrogen bonds. Our revised description of the halogen bond suggests that these interactions could be employed to influence the electronic properties ...
SW Germany, are investigated to understand the formation of such ore shoots and the transition from normal barite-fluorite-sulfide veins to these native element- and arsenide-dominated ore shoots. In the following, we chose to label the fluorite-barite-carbonate...
A tungsten-halogen incandescent lamp which includes a vitreous envelope, an inert gas and halogen fill, and two pairs of straight, parallel lead-in wires retained within the envelope's press-sealed end, each of said pairs having a tungsten filament supported thereon within the envelope. The pair...
A theoretical study was performed to examine intermolecular halogen bonds interactions in FArX⋯NCY complexes (X = Cl, Br and Y = H, F, Cl, Br, OH, NH2, CH3 and CN). Examination of the electrostatic potentials of the NCY monomers indicates that the addition of substituents has a large...
have a relevant impact on the wearing and performance characteristics of textiles. A quick look at recent literature [1] shows that various chemicals are frequently used as finishes to improve fabric performances. However, due to the intense pressure to ban harmful chemicals, such as halogen-...
That is, the heavier Ha-atoms exhibit a region of positive electrostatic potential (σ-hole) along the C–Ha bond and a belt of negative electrostatic potential (σ-lumps) around the atoms. The halogen bonding assemblies in both compounds were analyzed using density functional theory (DFT) ...
the entropy of the system. In this section we will closely examine the effects of enthalpy, but we will not spend too much time discussing the effects of entropy. To understand the effects of intermolecular forces, we need to go all the way back to bonds.溶液是一种均匀的混合物,其中溶质...
Lewis dot structure of Cl2 molecules. The single electron pair between two atoms represents a single covalent bond. Example: H2O, NH3 The two-electron pairs shared between two atoms represent the double bond. Example : O2, CO2 The three electron pairs shared between two atoms represent the ...