Vitalii Yu. Kotov

A hybrid halobismuthate light-harvesting material with an optical band gap of 1.70 eV

A new organic–inorganic hybrid material (C15H14N4)BiBr5·H2O with an optical band gap of 2.24 eV, having 1-D chains of bromobismuthate anions in its composition, has been obtained from an aqueous solution and characterized. The partial replacement of Br by I resulted in the formation of a thermally stable (<155 °C) black compound (C15H14N4)BiBrI4·H2O with an optical band gap of 1.70 eV, which can be proposed as a promising light-harvesting material for dye-sensitized solid-state solar cells. Further replacement of Br by I results in the formation of red-orange colored (C15H14N4)BiI5 with a band gap of 2.10 eV.

Kinetics of hydrogen-sodium ion exchange in acid zirconium phosphate

Abstract Proton diffusion in NaHZr(PO4)2–5H2O and Na2Zr(PO4)2–3H2O phases was examined by studying the kinetics of hydrogen–sodium ion exchange. Three regions characterized by an almost linear dependence of the apparent diffusion coefficients of the hydrogen ion on the pH values were obtained at pH

Anion-anion assembly in crystal of sodium nitroprusside.

The experimental charge density in the crystal of disodium pentacyanonitrosoferrate (sodium nitroprusside) dihydrate was analyzed in detail by means of Baders atoms in molecules theory. It was shown that nitroprusside anion is involved in relatively strong self-interactions through the nitroso group. The obtained results agree well with the spectroscopic data, indicating the tendency of the corresponding moiety to the formation of anion-anion association both in solutions and in the crystalline phase.

Black hybrid iodobismuthate containing linear anionic chains

Three hybrid 1,1′-(1,n-alkanediyl)bis(4-methylpyridinium) iodobismuthates 1–3 were prepared by a facile solution route and showed thermal stability in air up to 230 °C. The structures of solids 1 and 3 contain zero-dimensional anions, and the structure of 2 contains one-dimensional linear anionic chains [BiI5]n2n−. Photoluminescence (PL) in the spectral range between 600 and 750 nm was observed for 1 and 2. DFT calculations and optical studies confirmed that compounds 1–3 are semiconductors with band gaps of 1.73–2.10 eV, which correspond with their intense black (for 2) or red (for 1 and 3) colors. The optical absorption of 2 in the red spectral range is primarily due to charge transfer from the I5p orbitals at the top of the valence band to the Bi6p orbitals at the bottom of the conduction band.

Dipotassium sodium hexa­cyano­cobalt(III)

The polymeric structure of the title compound, K2Na[Co(CN)6], contains a three-dimensional network of centrosymmetric CoC6 and NaN6 octahedra and K+ cations.