Discriminative ionic capabilities on hydrogen-bond transition from the mode of ordinary water to (Mg, Ca, Sr)(Cl, Br)₂ hydration

It has been a long pursuit to discriminate the ionic roles of mono- and di-valent salt solutions in modulating the hydrogen bonding network and solution properties. We attended this issue by examining the effect of concentrated YX 2 (Y[dbnd]Mg, Ca, Sr; X[dbnd]Cl, Br) solvation on O:H–O bonds transition from the mode of ordinary water to hydration in terms of the number fraction f YX2 (C) and the segmental O:H–O bond phonon stiffness shift Δω(C) with C being the solute concentration. The invariant df Y (C) / dC at C ≤ <0.05 suggests that the small Y 2+ forms a constantly-sized hydration droplet with weak responding to interference of other ions because its hydrating H 2 O dipoles screen mostly its electric field. However, the number inadequacy of the highly-ordered hydrating H 2 O dipoles partially screens the large X − . The X − ↔ X − electrostatic repulsion weakens its electric field. The concentration-trend consistency of the f YX2 (C), the solution conductivity σ YX2 (C), and surface stress (contact angle) θ YX2 (C) for YX 2 solutions clarifies their common origin of ionic polarization. However, the Jones–Dale notion disobedience of the viscosity η YX2 (C) suggests the dominance of the inter-ion repulsion.Submitted/Accepted versionFinancial support received from Natural Science Foundation of China (Nos. 11872052(YL); 21875024(CQ)), and the Science Challenge Project (No. TZ2016001) of China are acknowledged

(H, Li)Cl and LiOH hydration : surface tension, solution conductivity and viscosity, and exothermic dynamics

We systematically examined the effect of (H, Li)Cl and LiOH solvation on the O:H[sbnd]O bond network deformation, surface tension (contact angle), solution electrical conductivity, thermomics, and viscosity evolution aiming to clarifying the functionalities for ions, lone pairs, and protons acting in these solutions. Results confirmed that H + and electron lone pair ‘:’ introduction turns out the (H 3 O + , OH − )·4H 2 O motifs and that the Li + and Cl − form each a hydration volume through the screened electrostatic polarization. The (H 3 O + , OH − )·4H 2 O turns an O:H[sbnd]O bond into the H ↔ H anti–HB that disrupts the HCl solution network and its surface tension and into the O:⇔:O super–HB compressor that raises the LiOH solution surface tension and viscosity, as well as the solution temperature during solvation. The Li + /Cl − ion reserves/reduces its hydration volume because of the complete/incomplete screen shielding by the ordered hydrating H 2 O dipoles and the Cl − ↔ Cl − repulsion at higher concentrations. The invariant/variant Li + /Cl − hydration volume dictates, respectively, the linear/nonlinear concentration dependence of the Jones–Dole viscosity. Except for the HCl/H 2 O surface tension and LiOH/H 2 O viscosity, the conductivity, surface tension, and viscosity of these solutions follow the Jones–Dole notion that underscores the faction of bond transition from the mode of water to hydration.Accepted versio