An Apatite-Group Praseodymium Carbonate Fluoroxybritholite: Hydrothermal Synthesis, Crystal Structure, and Implications for Natural and Synthetic Britholites.

Britholites are the lanthanide-silica-rich end-members of the apatite group, commonly studied for their optical properties. Here, we show ∼50-100 μm single crystals synthesized hydrothermally at 650-500 °C and 500-300 MPa composed of a solid solution between CaPr(SiO)F-fluorbritholite and CaPr(SiO)O-oxybritholite, with a significant carbonate component substitution, via C replacing Si. Single-crystal X-ray diffraction and density functional theory computations show that a planar carbonate group occupies the face of a now-vacant silica tetrahedron.

Co-Doping Effect of Mn and Eu on Luminescence in Strontiowhitlockite Phosphors.

A new series of Sr-based phosphates, SrMnEu(PO), were synthesized using the high-temperature solid-state method in air. It was found that these compounds have the same structure as strontiowhitlockite, which is a β-Ca(PO) (or β-TCP) structure. The concentration of Mn ions required to form a pure strontiowhitlockite phase was determined.

Thermal behavior of natural stellerite: high-temperature X-ray powder diffraction and IR spectroscopy study.

The thermal behavior of stellerite from the Savinskoye deposit (Transbaikalia, Russia), CaNaK(SiAl)O·53.39HO, was investigated by in situ high-temperature X-ray powder diffraction (HTXRPD) and ex situ HT infrared (IR) spectroscopic analysis. Four different HTXRPD experimental procedures were used to study the thermal behavior of the powder samples: (1) RT-750 °C, (2) RT-220 °C -RT, (3) 200-350-RT °C, and (4) 350-700 °C.

New Insights into the Crystal Chemistry of Elpidite, NaZr[SiO]·3HO and (NaCa□)Zr[SiO]·(3-X)HO, and Ab Initio Modeling of IR Spectra.

Elpidite belongs to a special group of microporous zirconosilicates, which are of great interest due to their capability to uptake various molecules and ions, e.g., some radioactive species, in their structural voids.

Time-resolved luminescence and excitation spectroscopy of Co-doped GdGaAlO scintillating crystals.

Cerium doped GdGaAlO (GGAG) single crystals as well as GGAG:Ce single crystals co-doped by divalent (Mg, Ca) and tetravalent (Zr, Ti) ions have been studied by means of time-resolved luminescence as well as the excitation luminescence spectroscopy in vacuum ultraviolet (VUV) and soft X-ray (XUV) spectral range. Tunable laser excitation was applied for time-resolved experiments in order to obtain luminescence decay curves under excitations in Ce, Gd and excitonic absorption bands. The influence of the co-dopant ions on the Ce luminescence decay kinetics is elucidated.

Structural and vibrational properties of agrellite.

Agrellite, NaCaSiOF, is a tubular silicate mineral which crystal structure is characterized by extended [SiO] tubes and has a two-dimensional channel system. The mineral is a representative of a complex silicate family which contains some structural voids but cannot be considered as microporous because of small channel widths. However, the channel system of such minerals is able to host single guest atoms, molecules or radicals which can affect their physical properties.

Synthesis and comparative assessment of antiradical activity, toxicity, and biodistribution of κ-carrageenan-capped selenium nanoparticles of different size: in vivo and in vitro study.

In the present study, water-soluble hybrid selenium-containing nanocomposites have been synthesised via soft oxidation of selenide-anions, preliminarily generated from elemental bulk-selenium in the base-reduction system 'NH-NaOH'. The nanocomposites obtained consist of SeNPs (4.6-24.

Optical properties of SrF and SrF:Ce crystals codoped with In.

The paper presents the results of a comprehensive study of effects that In ion impurities have on the optical properties of SrF and SrF:Ce crystals. The investigations were carried out both by optical spectroscopy methods and quantum chemical calculations. To estimate the effect of indium impurities on the optical band gap of the crystals, the DFT calculations were performed for SrF crystals doped with different concentrations of In ions.