Ceramics based around silicon aluminum oxynitrides are of both fundamental structural chemistry and technological interest. Certain oxynitride crystal structures allow very significant compositional variation through extensive Si/N exchange for Al/O, which implies a degree of atomic ordering. In this study, solid-state Si-29 MAS NMR and variable field 1D and 2D Al-27 MAS NMR measurements are combined with density functional theory calculations of both the structural and NMR interaction parameters for various points across the Y4Si2O7N2-Y4Al2O9 compositional range. This series provides numerous possibilities for significant variation of atomic ordering in the local ditetrahedral (Si,Al)(2)O7-xNx units. The two slightly structurally inequivalent aluminum sites in Y4Al2O9 are unambiguously assigned to the observed resonances. Computational findings on Y4Si2O7N2 demonstrate that the single observed Si-29 NMR resonance covers a range of local inequivalent silicon environments. For the first time, the MAS NMR and neutron diffraction data from the Y4SiAlO8N structure have been directly reconciled, thus establishing aspects of atomic order and disorder that characterize this system. This comparison suggests that, although the diffraction data indicates long-range structural order supporting a highly crystalline character, the short-range information afforded by the solid-state NMR measurements indicates significant atomic disorder throughout the (Si,Al)(2)O7-xNx units.

β'-Sialons (Si6-zAlzOzN8-z, where 0 ≤ z ≤ ∼4.2) are studied using a combination of 29Si and 27Al solid-state NMR, using magnetic fields of up to 20 T, powder X-ray diffraction, and density functional theory (DFT) calculations of both the structure and NMR parameters. Four different structural models have been proposed in the literature for the replacement of silicon and nitrogen by aluminum and oxygen within a β-Si3N4-structured lattice. Experimental data are presented for the variation with composition (z) of the unit cell parameters from diffraction and the local coordination units present suggested by NMR data. The experimental data are compared to the changes with composition in the DFT calculations of the structure and the NMR parameters according to the four models, allowing the models to be distinguished. It is shown that only one of these, the domain model, is fully consistent with all of the experimental data and is, therefore, a good structural model for β'-sialons. More speculatively, it is suggested that for the domain model, 27Al NMR data might provide a constraint on the thickness of its aluminum-rich layers.

In the context of improving J coupling measurements in disordered solids, strong coupling effects have been investigated in the spin-echo and refocused INADEQUATE spin-echo (REINE) modulations of three- and four-spin systems under magic-angle-spinning (MAS), using density matrix simulations and solid-state NMR experiments on a cadmium phosphate glass. Analytical models are developed for the different modulation regimes, which are shown to be distinguishable in practice using Akaike's information criterion. REINE modulations are shown to be free of the damping that occurs for spin-echo modulations when the observed spin has the same isotropic chemical shift as its neighbour. Damping also occurs when the observed spin is bonded to a strongly-coupled pair. For mid-chain units, the presence of both direct and relayed damping makes both REINE and spin-echo modulations impossible to interpret quantitatively. We nonetheless outline how a qualitative comparison of the modulation curves can provide valuable information on disordered networks, possibly also pertaining to dynamic effects therein.

Despite the extensive range of investigations on boronic acids (R-B(OH)2), some aspects of their reactivity still need to be explored. This is the case for the coordination chemistry of boronate anions (R-B(OH)3−), which has only recently been started to be studied. The purpose of this review is to summarize some of the key features of boronate ligands (and of their cyclic derivatives, benzoxaborolates) in materials: (i) coordination properties; (ii) spectroscopic signatures; and (iii) emerging applications.

This paper describes the synthesis and electrochemical properties of mesoporous titanium oxysulfides prepared through the chemical treatment of pristine mesoporous titanium oxide under various synthesis conditions. The materials were doped with sulfur by using hexamethyldisilathiane (HMDST), a strategy that was developed to improve the conductivity of the material, whilst also retaining the porosity and thermal stability. Varying amounts of HMDST and different synthesis temperatures were tested to optimize the surface area and electrochemical performance. Lower temperatures generally yielded materials with superior properties and, even though the conductivity was improved by using higher loading levels of HMDST, it also led to a drop in initial capacity at the highest synthesis temperature of 200 °C (137–41 mAh g −1 ). The best performing material was, thus, synthesized by using the highest level of HMDST (3.5 mL) at lower heating temperatures (100–150 °C). This set of conditions maximizes the combination of surface area, initial capacity, conductivity, and capacity retention, the latter of which was notably superior to that of the pristine material (81 vs. 35 %), emphasizing the overall success of this doping strategy in improving the electrochemical properties of these otherwise insulating materials.

87 Sr, 127 I and 119 Sn wideline NMR spectroscopy was successfully applied to inorganic and hybrid materials: (i) Sr derivatives of medicinal interest (Sr‐malonate, Sr‐pyrophosphates, mixed Ca,Sr‐fluoroapatites); (ii) apatitic structures acting as host matrices for iodine; and (iii) Sn‐derived oxo‐clusters which can be used as inorganic nanobuilding blocks. The BRAIN (BRoadband Adiabatic INversion) CP (Cross Polarization) approach (by Schurko et al .) was applied to a non integer quadrupolar nucleus ( 87 Sr, I=9/2). The sequence was used in combination with WURST (Wideband Uniform‐Rate Smooth‐Truncation) QCPMG (Quadrupolar Carr‐Purcell Meiboom‐Gill) for optimal sensitivity. We showed that 127 I WURST QCPMG experiments were sufficiently sensitive to allow rapid characterization of the incorporation of iodide (I − ) anions in lead vanadate/phosphate apatites, and that 127 I acted as a sensitive probe for the description of local disorder. 1 H/ 19 F → 119 Sn BRAIN CP was successfully applied to the detailed characterization of tin oxo‐clusters, using 1 H and 19 F as spin baths. We demonstrated that BRAIN CP can be effectively used as a tool of spectral editing leading to the estimation of spatial proximities between 119 Sn and 1 H/ 19 F nuclei.

Disordered sol-gel prepared calcium silicate biomaterials show significant, composition dependent ability to bond with bone. Bone bonding is attributed to rapid hydroxycarbonate apatite (HCA) formation on the glass surface after immersion in body fluid (or implantation). Atomic scale details of the development of the structure of (CaO)x(SiO2)1-x (x = 0.2, 0.3 and 0.5) under heat treatment and subsequent dissolution in simulated body fluid (SBF) are revealed through a multinuclear solid state NMR approach using one-dimensional (17)O, (29)Si, (31)P and (1)H. Central to this study is the combination of conventional static and magic angle spinning (MAS) and two-dimensional (2D) triple quantum (3Q) (17)O NMR experiments that can readily distinguish and quantify the bridging (BOs) and non-bridging (NBOs) oxygens in the silicate network. Although soluble calcium is present in the sol, the (17)O NMR results reveal that the sol-gel produced network structure is initially dominated by BOs after gelation, aging and drying (e.g. at 120 °C), indicating a nanoscale mixture of the calcium salt and a predominantly silicate network. Only once the calcium salt is decomposed at elevated temperatures do the Ca(2+) ions become available to break BO. Apatite forming ability in SBF depends strongly on the surface OH and calcium content. The presence of calcium aids HCA formation via promotion of surface hydration and the ready availability of Ca(2+) ions. (17)O NMR shows the rapid loss of NBOs charge balanced by calcium as it is leached into the SBF. The formation of nanocrystalline, partially ordered HCA can be detected via(31)P NMR. This data indicates the importance of achieving the right balance of BO/NBO for optimal biochemical response and network properties.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

43 Ca solid state NMR is comprehensively reviewed with applications to inorganic and molecular materials. ► 43 Ca solid state NMR is comprehensively reviewed up to early 2012. ► The effects of the physical properties of 43 Ca for NMR observation are outlined. ► A range of applications especially for inorganic materials are described. ► First principles calculation of NMR parameters is shown to augment experiments. ► Correlations of NMR interactions to local structure (e.g. Ca–O) are examined.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

This study demonstrates the utility of the novel Field Sweep Fourier Transform (FSFT) method for acquiring wideline (195)Pt NMR data from various sized Pt nanoparticles, Pt-Sn intermetallics/bimetallics used to catalyse oxidative processes in fuel cell applications, and various other related Pt3X alloys (X = Al, Sc, Nb, Ti, Hf and Zr) which can facilitate oxygen reduction catalysis. The (195)Pt and (119)Sn NMR lineshapes measured from the PtSn intermetallic and Pt3Sn bimetallic systems suggest that these are more ordered than other closely related bimetallic alloys; this observation is supported by other characterisation techniques such as XRD. From these reconstructed spectra the mean number of atoms in a Pt nanoparticle can be accurately determined, along with detailed information regarding the number of atoms present effectively in each layer from the surface. This can be compared with theoretical predictions of the number of Pt atoms in these various layers for cubo-octahedral nanoparticles, thereby providing an estimate of the particle size. A comparison of the common NMR techniques used to acquire wideline data from the I = 1/2 (195)Pt nucleus illustrates the advantages of the automated FSFT technique over the Spin Echo Height Spectroscopy (SEHS) (or Spin Echo Integration Spectroscopy (SEIS)) approach that dominates the literature in this area of study. This work also presents the first (195)Pt NMR characterisation of novel small Pt13 nanoclusters which are diamagnetic and thus devoid of metallic character. This unique system provides a direct measure of an isotropic chemical shift for these Pt nanoparticles and affords a better basis for determining the actual Knight shift when compared to referencing against the primary IUPAC shift standard (1.2 M Na2PtCl6(aq)) which has a very different local chemical environment.

Auf Germanium basierende Apatit-Verbindungen sind schnelle Oxidionenleiter, die möglicherweise in Brennstoffzellen Verwendung finden können. Mit einer Kombination aus 17O-Festkörper-NMR-Spektroskopie, atomistischen Berechnungen und DFT-Techniken ist es möglich, die Sauerstoff-Fehlstellen und neue kooperative Mechanismen der Ionenleitung aufzuklären. Das Bild zeigt Moleküldynamiksimulationen der Diffusion von Sauerstoff zwischen den Kanälen des untersuchten Apatits. Detailed facts of importance to specialist readers are published as "Supporting Information". Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

The method of in situ time-resolved high-energy X-ray diffraction, using the intrinsically highly collimated X-ray beam generated by the European Synchrotron Radiation Facility, is demonstrated. A specially designed cell, which allows the addition of liquid components, has been used to study the reaction mechanisms of a foamed bioactive calcia-silica sol-gel glass immersed in simulated body fluid. Analysis of the X-ray diffraction data from this experiment provides atomic distances, via the pair correlation functions, at different stages of the dissolution of the glass and of the associated calcium phosphate, and ultimately hydroxyapatite, i.e. bone mineral, formation. Hence, changes in the atomic scale structure can be analysed as a function of reaction time, giving an insight into the evolution of the structure of both the glass matrix and the hydroxyapatite surface growth.

27Al magic-angle spinning (MAS) nuclear magnetic resonance (NMR) spectra were acquired at 8.45, 14.1 and 16.45 T for a series of aluminium borates with the mullite structure (Al6−x B x O9, where x has nominal values of 1 to 4) augmented with 27Al multiple-quantum MAS NMR spectra at 8.45 T. Even though the 27Al NMR spectra are complex, simulation of the combined set of data produced a relatively well-defined set of parameters (e.g., quadrupolar interaction, isotropic chemical shift, etc.) for each site. The 11B MAS NMR spectra of the same compounds were also acquired at 14.1 T. Linear changes in the X-ray a-, b- and c-cell parameters with composition suggest that these compounds constitute a continuous series. Based on a Rietveld structural refinement of the compound synthesized as Al4B2O9, the resulting site occupancies and relative site distortions allow the identification of particular sites with specific NM resonances. Changes in the 27Al and 11B MAS NMR spectra of the related compounds with x = 1–4 show at the lowest Al contents a greater degree of asymmetry in the Al sites of the octahedral chains. A fairly distorted cross-linking tetrahedral site, which persists throughout the composition range, is accompanied in the lower Al compositions by two 5-fold coordinated Al–O units which are replaced by two more-regular tetrahedral Al–O sites as the Al content increases. In the compounds of lowest Al composition (i.e., highest B content) both the tetrahedral and trigonal cross-linking sites are distinguishable, but as the Al content increases, the BO4 units progressively disappear.

Nanocrystalline TiO2 samples were prepared using sol-gel techniques in a pure form and also Zener pinned with either silica or alumina to reduce the growth of the crystallites during the annealing process and to stabilize the anatase phase at high temperatures. These samples were studied using O-17, Al-27, and Si-29 nuclear magnetic resonance (NMR), X-ray diffraction (XRD), and electron microscopy. The silica pinning phase was found to successfully restrict nanocrystal growth as well as stabilize the anatase phase at temperatures up to 800 degrees C. The alumina phase had less of a pinning effect, and it reacted with the TiO2 to form tialite. O-17 NMR relaxation time measurements on enriched samples showed that the presence of the pinning phases also reduced the activation energy for the oxygen ion diffusion mechanism.

After a long history as devices for functional rehabilitation, large therapeutic balls and rolls have recently been advertised as cardiovascular training tools. The purpose of this study was to test the hypothesis that the heart rate (HR) response to exercise on the Physio-Roll™ would reach aerobic training levels (60-90% of predicted age-adjusted maximum HR [AAMHR]) in individuals of all fitness levels. Fourteen volunteers (mean age: 25 years, range 19-41) underwent an Åstrand bicycle ergometer test (mean predicted aerobic capacity: 46.2 ml.kg-1.min-1, range 30.5-65.2) in order to place them into different categories of cardiovascular fitness. On a subsequent day, subjects participated in an exercise session on the Physio-Roll™ consisting of 4 consecutive, uninterrupted 5 minute stages with each stage progressively increasing in intensity. Exercise progressed from level 1 (light bouncing) to level 2 (vigorous bouncing to the point of lift-off) to level 3 (vigorous bouncing with alternating leg kicks) to level 4(vigorous bouncing with alternating leg kicks and arm swings). HR means of the last two minutes of each stage were utilized for data interpretation. Level 1 mean HR was 82 bpm (range 58-117, 42.3% of AAMHR). Exercise at level 2 resulted in a mean HR of 101 bpm (range 74-126, 51.9% of AAMHR) and mean HR at level 3 was 127 bpm (range 98-159, 65.4% of AAMHR). For level 4, mean HR was 140 bpm (range 119-164, 67.0% of AAMHR). All participants, including those with superior aerobic capacity, exceeded 60% of AAMHR at intensity level 4. We conclude that most individuals should be able to reach and maintain aerobic training levels with appropriate exercise on the Physio-Roll™. We suggest that therapeutic balls and rolls offer a fun, creative and unique mode of aerobic training which not only trains the cardiovascular system, but challenges other systems such as proprioception and balance as well.

There have been great improvements in the quality of27Al NMR spectra from solids over the last decade. The impact of this technique on structure determination for a wide range of solids is briefly reviewed. Emphasis is placed on the effects arising from the presence of the quadrupolar interaction and strategies that allow unambiguous spectral interpretation. It is demonstrated that in addition to the chemical shift, the quadrupolar interaction itself can be a rich source of local information about solids. The insight obtained from27Al NMR into atomic level structure often contains surprises, such that previous models of structure and properties have to be reassessed.