Bi-doped MO-B2O3 (M=Ca, Sr, Ba) glasses were prepared by melting method. Excitation spectra, visible and infrared luminescence spectra were measured. Near infrared (NIR) emissions located at about 1190 nm with FWHM only 40 nm and at 1300 nm with FWHM about 200 nm can be observed in different samples when excited by 808 nm LD excitation. The two emission bands have different excitation bands. Red emission centered at 660 nm related to Bi2+ can be observed in some samples. The NIR emission at 1300 nm band disappears with the increase of optical basicity, while that of the NIR emission at 1190 nm band shows a contrary tendency. We proposed that the NIR emissions located at 1190 nm and 1300 nm originated from different bismuth centers. The infrared emission peak at about 1300 nm derives from low valence Bi ions according to the Duffy’s theory of optical basicity.

In this paper, M3(VO4)2:Eu3+(M = Ca, Sr, Ba) phosphors have been synthesized by high-temperature solid-state method. The phase composition and luminescence properties of the synthesized phosphors were characterized by X-ray powder diffraction and photoluminescence (PL) spectra, respectively. The influences of fluxing agent and doped concentration of rare-earth ions on PL properties of the phosphor were investigated. The results indicated that the energy transfers between VO4 3− and Eu3+ in the host occurred mainly via a dipole–dipole interaction mechanism. The increase in cation radius (from Ca2+ to Ba2+) in the host causes the emission peak originated from 5D0 → 7F2 transition of Eu3+ shifting from 615 to 621 nm, as well as decreasing the fluorescence lifetimes of Eu3+ from 0.77 to 0.19 ms and changing the CIE chromaticity coordinates from the orange-red region to the white region. Moreover, the emission colors of Ba3−x (VO4)2:xEu3+ can be firstly adjusted from cyan region to white light region via controlling the concentration of Eu3+. Temperature-dependent luminescence spectra proved the good thermal stability of the as-prepared phosphor. This work shows the potential application of europium-doped samples in UV converted pc-WLEDs.

The crystal structures of the M2NaIO6 series (M = Ca, Sr, Ba), prepared at 650 degrees C by ceramic methods, were determined from conventional laboratory X-ray powder diffraction data. Synthesis and crystal growth were made by oxidizing I with O2(air) to I7+ followed by crystal growth in the presence of NaF as mineralizator, or by the reaction of the alkali-metal periodate with the alkaline-earth metal hydroxide. All three compounds are insoluble and stable in water. The barium compound crystallizes in the cubic space group Fm3m (no. 225) with lattice parameters of a = 8.3384(1) angstrom, whereas the strontium and calcium compounds crystallize in the monoclinic space group P21/c (no. 14) with a = 5.7600(1) angstrom, b = 5.7759(1) angstrom, c = 9.9742(1) angstrom, = 125.362(1)degrees and a = 5.5376(1) angstrom, b = 5.7911(1) angstrom, c = 9.6055(1) angstrom, = 124.300(1)degrees, respectively. The crystal structure consists of either symmetric (for Ba) or distorted (for Sr and Ca) perovskite superstructures. Ba2NaIO6 contains the first perfectly octahedral [IO6]5 unit reported. The compounds of the ortho-periodates are stable up to 800 degrees C. Spectroscopic measurements as well as DFT calculations show a reasonable agreement between calculated and observed IR- and Raman-active vibrations.

The proton transport properties of La0.9M0.1YbO3-delta (M = Ba, Sr, Ca, Mg) were studied by the electrical conductivity measurement technique in the temperature range of 673-1173 K. The proton concentration was estimated by the weight changes due to the hydration reaction. The electrical conductivity and proton concentration of La0.9Ba0.1YbO3-delta were the highest in La0.9M0.1YbO3-delta. The electromotive force of a hydrogen gas concentration cell using La0.9Ba0.1YbO3-delta as the electrolyte was observed at 673-1073 K, and was in a good agreement with the theoretical values assuming that the proton transport number was unity. (c) 2013 Elsevier Ltd. All rights reserved.

The crystal structures of the M2NaIO6 series (M = Ca, Sr, Ba), prepared at 650 °C by ceramic methods, were determined from conventional laboratory X-ray powder diffraction data. Synthesis and crystal growth were made by oxidizing I– with O2(air) to I7+ followed by crystal growth in the presence of NaF as mineralizator, or by the reaction of the alkali-metal periodate with the alkaline-earth metal hydroxide. All three compounds are insoluble and stable in water. The barium compound crystallizes in the cubic space group Fm3m (no. 225) with lattice parameters of a = 8.3384(1) Å, whereas the strontium and calcium compounds crystallize in the monoclinic space group P21/c (no. 14) with a = 5.7600(1) Å, b = 5.7759(1) Å, c = 9.9742(1) Å, β = 125.362(1)° and a = 5.5376(1) Å, b = 5.7911(1) Å, c = 9.6055(1) Å, β = 124.300(1)°, respectively. The crystal structure consists of either symmetric (for Ba) or distorted (for Sr and Ca) perovskite superstructures. Ba2NaIO6 contains the first perfectly octahedral [IO6]5– unit reported. The compounds of the ortho-periodates are stable up to 800 °C. Spectroscopic measurements as well as DFT calculations show a reasonable agreement between calculated and observed IR- and Raman-active vibrations.

A magnetic anomaly has been found around 100K in La1-xMxFeO3 (M = Ca, Sr, and Ba) and Pr1-xSrxFeO3 with 0.05 <= x <= 0.4; the spontaneous magnetization of the weak ferromagnet increases below about 100K after cooling in a magnetic field. We propose a model in which Fe4+ ions populated by doped holes preferentially occupy one magnetic sublattice of the antiferromagnetic structure in LaFeO3 and PrFeO3 as a result of charge ordering, which induces an inequality between the sublattice magnetizations and modifies the system from the antiferromagnet to a ferrimagnet. The magnetization below the magnetic anomaly temperature is explained as that of a weak ferromagnet with the canted sublattice magnetizations of the ferrimagnet.

ESI-CID-MS/MS spectra of [MNO3](+) ions (M stands for Ca, Sr, Ba), the simplest ionic species composed of a metal and a nitrate group, are discussed in detail. These ions decompose through the loss of an NO molecule (with the formation of the MO2+ fragment ion) and/or the loss of an NO2 molecule (with the formation of the MO+ fragment ion). The efficiencies of these processes strongly depend on the electrostatic attraction between the metal and the oxygen atoms of the nitrate group. For the [CaNO3](+) ion the loss of an NO molecule is the only decomposition observed, for the [SrNO3](+) ion both processes are observed and their efficiencies depend on the collision energy, and for [BaNO3](+) ion the loss of an NO2 molecule is the dominant process. Alkali earth metal cations are not prone to reduction (M-II -> M-I), thus the formation of the M+ ion is a minor process. (C) 2015 Elsevier Ltd. All rights reserved.

Li3-2xMxPS4 (M =3D Ca or Mg) solid electrolytes were prepared by planetary ball-milling. Solid electrolytes that were amorphous in XRD were obtained with 0 <=3D x <=3D 0.115. A new crystalline phase was detected in samples with x >=3D 0.391. The addition of Ca2+ to the Li3PS4 matrix (x <=3D 0.115) resulted in reduction of the total conductivity at room temperature but conductivity enhancement was obtained at temperatures of 50 degrees C or higher. The sample Li2.88Ca0.06PS4 exhibited conductivity of about 9 mS cm(-1) at 90 degrees C, which was much improved compared with the conductivity of intrinsic Li3PS4 (2 mS cm(-1)).

The Eu3+ doped MWO4 (M=Ca, Sr, Ba) phosphors were synthesized via high temperature solid state reaction. The crystal phases of these phosphors were identified by X-ray diffraction. Shifts of the peaks in the structure were observed when Ca2+ sites in the host were completely occupied by the Sr2+ ions or Ba2+ ions. As a result of this replacement, the charge-transfer (CT) band exhibited a blue shift from CaWO4: Eu3+ to SrWO4: Eu3+ and BaWO4: Eu3+. This blue shift could be interpreted with the decreases of the bond covalence between the ligands (L) and the central ion (M) in matrix. In this work, red afterglow originated from the 5D0-7FJ (J=0,1,2,3,4) transitions of Eu3+ could clearly be observed after samples were excited at 254 nm. The thermoluminescence (TL) spectra showed that there were five traps levels in CaWO4: Eu3+ sample and two traps levels in CaWO4: Eu3+ and CaWO4: Eu3+ samples, respectively. The possible explanation of this afterglow phenomenon was also discussed in detail.

The Eu3+ doped MWO4 (M=Ca, Sr, Ba) phosphors were synthesized via high temperature solid state reaction. The crystal phases of these phosphors were identified by X-ray diffraction. Shifts of the peaks in the structure were observed when Ca2+ sites in the host were completely occupied by the Sr2+ ions or Ba2+ ions. As a result of this replacement, the charge-transfer (CT) band exhibited a blue shift from CaWO4: Eu3+ to SrWO4: Eu3+ and BaWO4: Eu3+. This blue shift could be interpreted with the decreases of the bond covalence between the ligands (L) and the central ion (M) in matrix. In this work, red afterglow originated from the 5D0-7FJ (J=0,1,2,3,4) transitions of Eu3+ could clearly be observed after samples were excited at 254 nm. The thermoluminescence (TL) spectra showed that there were five traps levels in CaWO4: Eu3+ sample and two traps levels in CaWO4: Eu3+ and CaWO4: Eu3+ samples, respectively. The possible explanation of this afterglow phenomenon was also discussed in detail.

Dialkali halides have been widely studied because of their large transparency range. The structural, elastic, electronic and optical properties of MF 2 (M = Mg, Ca, Sr, Ba, Ra) compounds in fluorite structure have been studied by using self consistent full potential linearized augmented plane wave (FLAPW) method with Wu-Cohen generalized gradient approximation (WC-GGA) and the modified Becke-Johnson potentials. Lattice constant varies inversely to bulk modulus by changing the cation from Mg to Ra in MF 2. All the compounds are found to have wide indirect band gap. Refractive index, reflectivity and optical conductivity are calculated to explain the optical nature of these compounds. [All rights reserved Elsevier].

The five ternary intermetallic compounds M2Pt6Al15 (M =3D Ca, Sc, Y, La, Lu) were prepared from the elements by arc-melting. The crystal structure was determined via single crystal X-ray diffraction. The title compounds crystallize in a superstructure of the RE0.67Pt2Al5 type structure (P6(3)/mmc) in the monoclinic crystal system with space group P12(1)/m1 (Sc2Pt6Al15 : a=3D 734.19(2), b =3D 1628.96(10), c =3D 734.19(2) pm, beta =3D 119.999(3)degrees; wR =3D 0.0356, 3034 F-2 values, 68 variables). The superstructure can be derived by the superspace formalism using (3 + 2)D or (3 + 1)D interpretations of the diffraction data. The structural relation to the subcell structure is discussed on the basis of a group-subgroup scheme. In the crystal structure strongly bonded [Pt2Al4](delta-) slabs are alternatingly stacked with ordered layers containing M atoms and Al-3 triangles.

Lanthanum cobaltates modified by alkaline-earth-metal (0.10 mol%) and lithium (0.05 mol%) ions were synthesized. The samples had an orthorhombic distorted perovskite-like structure according to x-ray diffraction phase analysis. Addition of Li+ and M2+ (M = Ca, Sr, Ba) to the LaCoO3 matrix was shown to increase the unit-cell parameters, the optical band width (E-g), and the average Co oxidation state (Con+). Pure and doped LaCoO3 were characterized by the presence of paramagnetic centers as isolated structural and surface Co2+ ions and adsorption complexes [Co3 + a <-aEuro parts per thousand O (2) (-) ](center dot) on the surface of the oxide matrix at a concentration that increased in the order Ba > Sr > Ca. The cobaltates were found to possess Mott hopping conduction in the temperature range 77-298 K.

Lanthanum cobaltates modified by alkaline-earth-metal (0.10 mol%) and lithium (0.05 mol%) ions were synthesized. The samples had an orthorhombic distorted perovskite-like structure according to x-ray diffraction phase analysis. Addition of Li+ and M2+ (M = Ca, Sr, Ba) to the LaCoO3 matrix was shown to increase the unit-cell parameters, the optical band width (E-g), and the average Co oxidation state (Con+). Pure and doped LaCoO3 were characterized by the presence of paramagnetic centers as isolated structural and surface Co2+ ions and adsorption complexes [Co3 + a <-aEuro parts per thousand O (2) (-) ](center dot) on the surface of the oxide matrix at a concentration that increased in the order Ba > Sr > Ca. The cobaltates were found to possess Mott hopping conduction in the temperature range 77-298 K.