Sites and Mobility of Lithium along the LiTiIn(PO) (0 ≤ ≤ 2) Series Deduced by XRD, NMR, and Impedance Spectroscopy.

The structure and Li conductivity has been investigated in the LiTiIn(PO) (0 ≤ ≤ 2) series prepared by the ceramic route at 900 °C. The XRD patterns of 0 ≤ ≤ 0.2 samples show the presence of rhombohedral (S.

Si Magic Angle Spinning Nuclear Magnetic Resonance, Fourier-Transform Infrared, and Monte Carlo Study of Synthetic Tetrasilicic Magnesium Mica Solid Solutions.

The parallel Si magic angle spinning nuclear magnetic resonance (MAS NMR) and Fourier-transform infrared study of synthetic micas made it possible to compare structural features of the tetrasilicic magnesium mica K(Mg□) SiO(OH) (TMM) and their K(Mg)(SiMg)O(OH) (TMMA) and K(Mg)(SiBe)O(OH) (TMMB) derivatives. In the TMM mica, SiO tetrahedra are elongated in the plane and shortened along the * direction with respect to those of the phlogopite (Phl) K(Mg)(SiAl)O(OH). The substitution of Si by R (Mg or Be) produces, besides the Si MAS NMR signal of Si (3Si) at -91.

Self-diffusion in polycrystalline Li Ti Al (PO) (0.2 ≤ ≤ 0.4) samples followed by Li PFG (pulse field gradient) NMR spectroscopy.

Short and long range lithium motions in powder Li Ti Al (PO) (LTAP) NASICON compounds prepared by ceramic ( = 0.2 and 0.4) and sol-gel ( = 0.

Hybrid Cements: Mechanical Properties, Microstructure and Radiological Behavior.

The use of more eco-efficient cements in concretes is one of the keys to ensuring construction industry sustainability. Such eco-efficient binders often contain large but variable proportions of industrial waste or by-products in their composition, many of which may be naturally occurring radioactive materials (NORMs). This study explored the application of a new gamma spectrometric method for measuring radionuclide activity in hybrid alkali-activated cements from solid 5 cm cubic specimens rather than powder samples.

Electrical and Structural Properties of LiAlTi(PO)-Based Ceramics Prepared with the Addition of LiSiO.

The currently studied materials considered as potential candidates to be solid electrolytes for Li-ion batteries usually suffer from low total ionic conductivity. One of them, the NASICON-type ceramic of the chemical formula LiAlTi(PO), seems to be an appropriate material for the modification of its electrical properties due to its high bulk ionic conductivity of the order of 10 S∙cm. For this purpose, we propose an approach concerning modifying the grain boundary composition towards the higher conducting one.

New Approach for the Determination of Radiological Parameters on Hardened Cement Pastes with Coal Fly Ash.

Supplementary cementitious materials (SCMs) in industrial waste and by-products are routinely used to mitigate the adverse environmental effects of, and lower the energy consumption associated with, ordinary Portland cement (OPC) manufacture. Many such SCMs, such as type F coal fly ash (FA), are naturally occurring radioactive materials (NORMs). Ra, Th and K radionuclide activity concentration, information needed to determine what is known as the gamma-ray activity concentration index (ACI), is normally collected from ground cement samples.

The structure of kaliophilite KAlSiO, a long-lasting crystallographic problem.

Kaliophilite is a feldspathoid mineral found in two Italian magmatic provinces and represents one of the 12 known phases with composition close to KAlSiO. Despite its apparently simple formula, the structure of this mineral revealed extremely complex and resisted structure solution for more than a century. Samples from the Vesuvius-Monte Somma and Alban Hills volcanic areas were analyzed through a multi-technique approach, and finally the crystal structure of kaliophilite was solved using 3D electron diffraction and refined against X-ray diffraction data of a twinned crystal.

Cation Miscibility and Lithium Mobility in NASICON LiTiSc(PO) (0 ≤ x ≤ 0.5) Series: A Combined NMR and Impedance Study.

Rhombohedral NASICON compounds with general formula LiTiSc(PO) (0 ≤ x ≤ 0.5) have been prepared using a conventional solid-state reaction and characterized by X-ray diffraction (XRD), nuclear magnetic resonance (NMR), and impedance spectroscopy. The partial substitution of Ti by Sc and Li in pristine LiTi(PO) increases unit-cell dimensions and the number of charge carriers.

Water-Free Proton Conduction in Discotic Pyridylpyrazolate-based Pt(II) and Pd(II) Metallomesogens.

In this work we report on water-free proton conductivity in liquid-crystal pyridylpyrazolate-based Pt(II) and Pd(II) complexes [M(pz(R(n,n)py))2] (pz(R(n,n)py) = 3-(3,5-dialkyloxyphenyl)-5-(pyridin-2-yl)pyrazolate, R(n,n) = C6H3(OCnH2n+1)2; n = 4, 12, 16, M = Pd; n = 12, M = Pt) with potential application as electrolyte materials in proton exchange membrane fuel cells. The columnar ordering of the complexes in the liquid-crystalline phase opens nanochannels, which are used for fast proton exchange as detected by impedance spectroscopy and NMR. The NMR spectra indicate that the proton conduction mechanism is associated with a novel C-H···N proton transfer, which persists above the clearing point of the material.

Microstructural and Mechanical Properties of Alkali Activated Colombian Raw Materials.

Microstructural and mechanical properties of alkali activated binders based on blends of Colombian granulated blast furnace slag (GBFS) and fly ash (FA) were investigated. The synthesis of alkali activated binders was conducted at 85 °C for 24 h with different slag/fly ash ratios (100:0, 80:20, 60:40, 40:60, 20:80, and 0:100). Mineralogical and microstructural characterization was carried out by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX) and Nuclear magnetic resonance (NMR).

Synthesis and characterization of NaNiF3·3H2O: an unusual ordered variant of the ReO3 type.

A new hydrated sodium nickel fluoride with nominal composition NaNiF3·3H2O was synthesized using an aqueous solution route. Its structure was solved by means of ab initio methods from powder X-ray diffraction and neutron diffraction data. NaNiF3·3H2O crystallizes in the cubic crystal system, space group Pn3̅ with a = 7.

Insight into the channel ion distribution and influence on the lithium insertion properties of hexatitanates A2Ti6O13 (A = Na, Li, H) as candidates for anode materials in lithium-ion batteries.

Li(2)Ti(6)O(13) and H(2)Ti(6)O(13) were easily synthesized from Na(2)Ti(6)O(13) by successive Na(+)-Li(+)-H(+) ion exchange. The crystal structures of Na(2)Ti(6)O(13), Li(2)Ti(6)O(13) and H(2)Ti(6)O(13) were investigated using neutron powder diffraction. Monovalent A(+) cations (Na, Li and H) have been located using difference Fourier analysis.

Insight into ramsdellite LI(2)Ti(3)O(7) and its proton-exchange derivative.

Despite being proven to be a good lithium-ion conductor 30 years ago, the crystal structure of the ramsdellite-like Li(2)Ti(3)O(7) has remained uncertain, with two potential models for locating the lithium ions in the structure. Although the model presently accepted states that both lithium and titanium occupy the octahedral sites in the framework, evidence against this model are provided by (6)Li and (7)Li MAS NMR spectroscopy. Thus, about 14% of these octahedral positions are empty since no lithium in octahedral coordination is present in the material.

Layered microporous tin(IV) bisphosphonates.

This article reports the hydrothermal synthesis and characterization of two new series of porous tin(IV) phosphonophenoxyphenylphosphonates with controlled pore size distributions, using as precursor the 4-(4'-phosphonophenoxy)phenyl phosphonic acid, [H2O3P-C6H4]2-O. Supermicroporous solids (S(BET), 300-400 m2 g(-1)) were obtained employing n-alcohol (C1-C6)-water mixtures (solvents ratio 1 : 1), in the presence of hydrofluoric acid. X-Ray powder diffraction shows that these compounds are semi-crystalline and the local environments around the phosphorus and tin elements have been studied by 31P and 119Sn MAS-NMR spectroscopy, respectively.

Structural characterization and NMR study of NaNbWO(6) and its proton-exchanged derivatives.

The structural characterization of NaNbWO(6), prepared by the ceramic route, has been performed. Electron diffraction has shown the presence of two related phases in a 1:1 ratio, whose lattice parameters correspond to those of the well-known tetragonal tungsten bronzes (TTB) and those of a monoclinically distorted phase. In addition to basic unit cells, the morphology of the two phases has been found to be similar, but they present a slight difference in the W/Nb ratio.