Cs7Sm11[TeO3]12Cl16 and Rb7Nd11[TeO3]12Br16, the new tellurite halides of the tetragonal Rb6LiNd11[SeO3]12Cl16 structure type

The authors thank the Russian Foundation for Basic Researches for the support of this work under Grants No. 14-03-00604_a and 12-03-92604-KO_a. The X-ray study of compound II was made possible due to M.V. Lomonosov Moscow State University Programm of Development. PL thanks the University of St Andrews and EPSRC for DTA Studentships to CB and LJD.Two new rare-earth – alkali – tellurium oxide halides were synthesized by a salt flux technique and characterized by single-crystal X-ray diffraction. The structures of the new compounds Cs7Sm11[TeO3]12Cl16 (I) and Rb7Nd11[TeO3]12Br16 (II) (both tetragonal, space group I4/mcm) correspond to the sequence of [MLn11(TeO3)12] and [M6×16] layers and bear very strong similarities to those of known selenite analogs. We discuss the trends in similarities and differences in compositions and structural details between the Se and Te compounds; more members of the family are predicted.PostprintPeer reviewe

Complex Uranyl Dichromates Templated by Aza-Crowns

Three new uranyl dichromate compounds templated by aza-crown templates were obtained at room temperature by evaporation from aqueous solutions: (H2diaza-18-crown-6)2[(UO2)2(Cr2O7)4(H2O)2](H2O)3 (1), (H4[15]aneN4)[(UO2)2(CrO4)2(Cr2O7)2(H2O)] (H2O)3.5 (2) and (H4Cyclam)(H4[15]aneN4)2[(UO2)6(CrO4)8(Cr2O7)4](H2O)4 (3). The use of aza-crown templates made it possible to isolate unprecedented and complex one-dimensional units in 2 and 3, whereas the structure of 1 is based on simple uranyl-dichromate chains. It is very likely that the presence of relatively large organic molecules of aza-crown ethers does not allow uranyl chromate chain complexes to condense into the units of higher dimensionality (layers or frameworks). In general, the formation of 1, 2, and 3 is in agreement with the general principles elaborated for organically templated uranyl compounds. The negative charge of the [(UO2)(Cr2O7)2(H2O)]2−, [(UO2)2(CrO4)2(Cr2O7)2(H2O)]4− and [(UO2)3(CrO4)4(Cr2O7)2]6− one-dimensional inorganic motifs is compensated by the protonation of all nitrogen atoms in the molecules of aza-crowns

Uranyl Sulfate Nanotubules Templated by N-phenylglycine

The synthesis, structure, and infrared spectroscopy properties of the new organically templated uranyl sulfate Na(phgH+)7[(UO2)6(SO4)10](H2O)3.5 (1), obtained at room temperature by evaporation from aqueous solution, are reported. Its structure contains unique uranyl sulfate [(UO2)6(SO4)10]8− nanotubules templated by protonated N-phenylglycine (C6H5NH2CH2COOH)+. Their internal diameter is 1.4 nm. Each of the nanotubules is built from uranyl sulfate rings sharing common SO4 tetrahedra. The template plays an important role in the formation of the complex structure of 1. The aromatic rings are stacked parallel to each other due to the effect of π–π interaction with their side chains extending into the gaps between the nanotubules

New clathrate-like compound Eu7Cu44Sb23-δ: synthesis, crystal and electronic structure, and the effect of As-for-Sb substitution on the magnetic properties

A new intermetallic compound, ternary antimonide Eu7Cu44Sb23-delta [Fm-3m, a = 17.4346(1)angstrom, delta = 0.5(1)] is reported. The compound forms a continuous substitutional solid solution with its Eu7Cu44As23 archetype. The gradual substitution of Sb for As evokes partial disorder in the copper-pnictogen framework that becomes more pronounced with an increase of the Sb content and changes magnetic properties. Whereas Eu7Cu44As23 is metallic ferromagnet below 17 K, Eu7Cu44Sb23-delta shows paramagnetic behavior down to 1.8 K according to the magnetic measurements, while retaining metallic properties according to the DFT calculations. The origin of the disorder, the structure-property relationships, as well as prospects of further substitution in the anionic sub lattice are discussed

Pb6O5(NO3)2: A Nonlinear Optical Oxynitrate Structurally Based on Lead Oxide Framework

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала.A high second harmonic generation response is demonstrated by a Pb6O5(NO3)2 lead oxynitrate whose identity was verified upon reinvestigation of the PbO–Pb(NO3)2 system. Its crystal structure exhibits a unique cationic [Pb6O5]2+ framework hosting orientationally ordered NO3– triangles in the channels. Easy preparation and high thermal stability (until ∼500 °C in air) suggest it to be a new promising NLO material

Two New Arsenides, Eu₇Cu₄₄As₂₃ and Sr₇Cu₄₄As₂₃, With a New Filled Variety of the BaHg₁₁ Structure

Two new ternary arsenides, namely, Eu₇Cu₄₄As₂₃ and Sr₇Cu₄₄As₂₃, were synthesized from elements at 800 °C. Their crystal structure represents a new filled version of the BaHg₁₁ motif with cubic voids alternately occupied by Eu­(Sr) and As atoms, resulting in a 2 × 2 × 2 superstructure of the aristotype: space group <i>Fm</i>3̅<i>m</i>, <i>a</i> = 16.6707(2) Å and 16.7467(2) Å, respectively. The Eu derivative exhibits ferromagnetic ordering below 17.5 K. In agreement with band structure calculations both compounds are metals, exhibiting relatively low thermopower, but high electrical and low thermal conductivity