Crystal structure of [Pt(NH3)5Cl](PO4) · 2H2O

Polycrystals of [Pt(NH₃)₅Cl](PO₄)·2H₂O complex salt are analyzed using single crystal XRD (STADI-P autodiffractometer, CuKα₁-radiation, position sensitive detector). Crystallographic characteristics are as follows: a = 9.2447(2) ?, b = 7.3122(1) ?, c = 9.2005(1) ?, β= 109.938(1)°, P2₁/m space group, V = 584.67(2) ?³.     

Synthesis and physicochemical study of M<Subscript>4</Subscript>Na<Subscript>2</Subscript>V<Subscript>10</Subscript>O<Subscript>28</Subscript> · 10H<Subscript>2</Subscript>O (M=K,Rb, NH<Subscript>4</Subscript>)

The formation conditions and physicochemical properties of binary decavanadates M₄Na₂V₁₀O₂₈ · 10H₂O (M=K, Rb, NH₄), synthesized by crystallization from saturated solutions of the NaVO₃-MH₂AsO₄-H₂O systems, were studied by chemical analysis, X-ray powder diffraction, microscopy, thermogravimetry, and IR spectroscopy. To optimize the synthesis conditions of M₄Na₂V₁₀O₂₈ · 10H₂O, the ( 1-x)NaVO₃ · 2H₂O · xMH2AsO4-H₂O (0.2 ≤ x ≤ 0.8) isomolar series method was applied to studying the interaction in the NaVO₃-MH₂AsO₄-H₂O systems (M = K, Rb, Cs) at the 0.4 mol/L total molar concentration of NaVO₃ and MH₂AsO₄ in solutions. The studied M₄Na₂V₁₀O₂₈ · 10H₂O compounds were shown to be isostructural with triclinic crystals (Z= 1, space group P $ \bar 1 $ \bar 1 ), and their unit cell parameters were estimated.     

Determination of the Refractive Index of Dielectrics by Means of Light‐Induced Diffraction Gratings

Consideration is given to the possibilities of measuring the refractive index n of dielectric samples by means of spontaneous gratings produced by an spolarized laser beam in a photosensitive thin film applied to a sample in vacuum. With the specific choice of the film thickness, the value of n is determined from diffraction measurements of the period of a spontaneous grating with the error n = ±0.002. The method allows measurement of n isotropic and anisotropic samples within the range 1.32.5 on plane and cylindrical surfaces with the area determined by the section of the laser beam that induces the spontaneous grating. Examples of measurements of n on plane surfaces of glasses, a LiNbO₃ crystal, and on the cylindrical surface of a ruby rod are presented.     

Electronic states of boron in superconducting MgB2 studied by11B NMR

Nuclear magnetic resonance (NMR) spectra and nuclear spin-lattice relaxation rateT ₁⁻¹ of¹¹B have been measured in superconducting polycrystalline MgB₂ with 7_c^ons = 39.5 K. It is shown that (T ₁T⁻¹ and the Knight shiftK _s are independent of temperature and nearly isotropic aboveT _c. Both of these quantities are decreased gradually in going to the superconducting state. According to NMR data the density of states near the Fermi level is flat at the scale of about 500 K. Some conclusions on the orbital content of the density of states at the Fermi level were drawn and compared with the results of the band structure calculations.     

Synthesis,crystal structure,and luminescence properties of CaY2Ge3O10:Ln3+, Ln = Eu,Tb

The crystal structure and luminescence properties of CaY₂Ge₃O₁₀:Ln³⁺ (Ln = Eu, Tb) germanates synthesized via a conventional solid-state reaction and an ethylenediaminetetraacetic acid complexing process are studied. The CaY_{2 ? x} Ln _x Ge₃O₁₀ (Ln = Eu, Tb; x = 0–1.0, 2.0; Δx = 0.1) solid solutions have a monoclinic structure (space group P2₁/c, Z = 4), in which dopant ions occupy three nonequivalent noncentrosymmetric sites with different Ca²⁺/Ln³⁺ ratios. The effect of the synthesis methods, dopant concentrations, and excitation wavelengths on the luminescence properties of the compounds obtained is determined.     

On the problem of the role played by photoemission in the mechanism of a discharge with a hollow cathode

The paper investigates the arc voltage and certain characteristics of the luminescence of a discharge in helium with a cylindrical hollow cathode in a magnetic field. Based on a comparison of the effect of a magnetic field on the electrical and optical characteristics of the discharge, the role played in the discharge mechanism by photoemission from the cathode is discussed.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 15, No. 4, pp. 631–633, April, 1972.     

Preparation specifics and properties of AMn<Subscript>3</Subscript>V<Subscript>4</Subscript>O<Subscript>12</Subscript> (А = Ca,Ce, and Sm) high-pressure phases

Perovskite-like phases AMn₃V₄O₁₂ (A = Ca, Ce, and Sm) were prepared under borothermic conditions (p = 7.0–9.0 GPa, T = 700–1100°C). Their X-ray diffraction structure (space group Im \(\bar 3\), Z = 2) was determined, and unit cell parameters were calculated: for CaMn₃V₄O₁₂: а = 7.40824(3) Å, for SmMn₃V₄O₁₂: а = 7.45280(8) Å, and for CeMn₃V₄O₁₂: а = 7.46965(4) Å. The temperature-dependent electrical resistivity (10–300 K) and magnetic susceptibility (2–300 K) of the prepared phases were studied.     

Thermobaric synthesis, structure, and properties of Dy x Cu3V4O12

The perovskite-like compound Dy _x Cu₃V₄O₁₂ (x = 0.67–0.75) is synthesized under high pressure (P = 4.0–9.0 GPa) and temperature (T = 1000°C). Its crystal structure is determined (Im-3 space group, Z = 2, a = 7.29348(7) Å) by means of powder X-ray diffraction. The basic lengths and bond angles are defined. It is found that the high-pressure phase of Dy _x Cu₃V₄O₁₂ is characterized by metallic conductivity and paramagnetic properties.