Resolving old problems with layered polytungstates related to hexagonal tungsten bronze: phase formation, structures, crystal chemistry and some properties.

A 60-year-old problem with the atomic arrangements and exact compositions of alkali polytungstates related to hexagonal tungsten bronze (HTB) was solved. The systems WO-WO ( = K, Rb) were restudied and the average monoclinic layered structures of stoichiometric polytungstates WO ( = K, Rb, Cs, Tl) and WO ( = K, Rb, Cs) were first successfully determined. The structures resemble those of "MoWO" and "MoWO" (J.

Ionic Transport in CsNO-Based Nanocomposites with Inclusions of Surface Functionalized Nanodiamonds.

Composite solid electrolytes (1-x) CsNO-xND, where ND are nanodiamonds, including those after liquid-phase and gas-phase oxidation and reduction functionalization, were prepared, and their properties investigated by XRD, analysis of BET nitrogen adsorption isotherms, IR spectroscopy and impedance spectroscopy. The electrical conductivity of composites (1-x) CsNO-xND obeys the Arrhenius dependence and has a maximum at x = 0.95 regardless of the ND pretreatment.

Triple molybdates KNaM(MoO) (M = Ni, Mg, Co) and KLiMg(MoO) isotypic with II-NaFe(AsO) and yurmarinite: synthesis, potassium disorder, crystal chemistry and ionic conductivity.

The triple molybdates KNaM(MoO) (M = Ni, Mg, Co) and KLiMg(MoO) were found upon studying the corresponding ternary molybdate systems, and their structures, thermal stability and electrical conductiviplusmnty were investigated. The compounds crystallize in the space group R3c and are isostructural with the sodium-ion conductor II-NaFe(AsO) and yurmarinite, Na(Fe, Mg, Cu)(AsO); their basic structural units are flat polyhedral clusters of the central M1O octahedron sharing edges with three surrounding M2O octahedra, which combine with single NaO octahedra and bridging MoO tetrahedra to form open three-dimensional (3D) frameworks where the cavities are partially occupied by disordered potassium (sodium) ions. The split alkali-ion positions in KNaM(MoO) (M = Ni, Mg, Co) give their structural formulae as [(K,Na)□)](Na)[M1][M2](MoO), whereas the lithium-containing compound (K□)(MgK)(LiMg)Mg(MoO) shows an unexpected (Mg, K) isomorphism, which is similar to (Mn, K) and (Co, K) substitutions in isostructural KLiM(MoO) (M = Mn, Co).