Effects of Difference in Ionic Radii on Chemical Ordering in Mixed‐Cation Silicate Glasses: Insights from Solid‐State 17O and 7Li NMR of Li–Ba Silicate Glasses

Understanding of the extent of cation disorder and its effect on the properties in glasses and melts is among the fundamental puzzles in glass sciences, materials sciences, physical chemistry, and geochemistry. Particularly, the nature of chemical ordering in mixed‐cation silicate glasses is not fully understood. The Li–Ba silicate glass with significant difference in the ionic radii of network‐modifying cations (~0.59 Å) is an ideal system for revealing unknown details of the effect of network modifiers on the extent of mixing and their contribution to the cation mobility. These glasses also find potential application as energy and battery materials. Here, we report the detailed atomic environments and the extent of cation mixing in Li–Ba silicate glasses with varying X_BaO [BaO/(Li₂O + BaO)] using high‐resolution solid‐state nuclear magnetic resonance (NMR) spectroscopy. The first ¹⁷O MAS and 3QMAS NMR spectra for Li–Ba silicate glasses reveal the well‐resolved peaks due to bridging oxygen (Si–O–Si) and those of the nonbridging oxygens including Li–O–Si and mixed {Li, Ba}–O–Si. The fraction of Li–O–Si decreases with an increase in X_BaO and is less than that predicted by a random Li–Ba distribution. The result demonstrates a nonrandom distribution of Li⁺ and Ba⁺ around NBOs characterized by a prevalence of the dissimilar Li–Ba pair. Considering the previously reported experimental results on chemical ordering in other mixed‐cation silicate glasses, the current results reveal a hierarchy in the degree of chemical order that increases with an increase in difference in ionic radius of the cation in the glasses [e.g., K–Mg (~0.66 Å) ≈Ba–Mg (~0.63 Å) ≈Li–Ba (~0.59 Å) > Na–Ba (~0.33 Å) > Na–Ca (~0.02 Å)]. The ⁷Li MAS NMR spectra of the Li–Ba silicate glasses show that the peak maximum increases with increasing X_BaO, suggesting that the average Li coordination number and thus Li–O distance decrease slightly with increasing X_BaO, potentially leading to an increased activation energy barrier for Li diffusion. Current experimental results confirm that the degree of chemical ordering due to a large difference in ionic radii controls the transport properties of the mixed‐cation silicate glasses.     

Structure of alkali borosilicate glasses and melts according to Raman spectroscopy data

Using the technique of high-temperature Raman scattering spectroscopy, we studied the structure of glasses and melts of the systems Na₂O-B₂O₃-SiO₂, K₂O-B₂O₃-SiO₂, and Cs₂O-B₂O₃-SiO₂ with the relations ${{X_{M_2 O} } \mathord{\left/ {\vphantom {{X_{M_2 O} } X}} \right. \kern-0em} X}_{B_2 O_3 } = 1$ (M = Na, K, Cs) and ${{X_{SiO_2 } } \mathord{\left/ {\vphantom {{X_{SiO_2 } } X}} \right. \kern-0em} X}_{B_2 O_3 } = 3$ and 4/3. Based on the analysis of the registered spectra, we have shown that, at a high content of SiO₂, the disordered network of glasses is composed of the Q ⁴, Q ³, [BO_4/2]^? tetrahedrons and BO_3/2 triangles. When the content of SiO₂ reduces, asymmetric borate triangles BØ_2/2O^? are formed in the structure in addition. A substantial part of borate tetrahedrons are included into the content of mixed borosilicate rings composed of two silicon-oxygen and two boron-oxygen tetrahedrons. The amount of borate structural units joined into purely borate superstructural groups increases with a decrease of the silicon oxide content, depends on the alkali kation type, and grows in the direction from Cs to Na. An increase in the temperature causes a decrease of various types of rings and growth of the concentration of asymmetric triangles. Both in glasses and melts, the fraction of the BO_2/2O^? triangles depends on the alkali cation type and increases in the succession Cs → K → Na. The results obtained present the basis to suggest that there is some differentiation in the mechanisms of structural reconstruction of the glasses under study by their heating depending on the modifying oxide.     

Cation field-strength effects on ion irradiation-induced mechanical property changes of borosilicate glass structures

We examine the impact of the glass network-modifier cation field strength (CFS) on ion irradiation-induced mechanical property changes in borosilicate (BS) glasses for the ternary M₂O–B₂O₃–SiO₂ systems with M = {Na, K, Rb} and the quaternary [0.5M₍₂₎O–0.5Na₂O]–B₂O₃–SiO₂ systems with M = {Li, Na, K, Rb Mg, Ca, Sr, Ba}. ¹¹B nuclear magnetic resonance (NMR) experiments on the as-prepared BS glasses yielded the fractional population of four-coordinated B species (B^[4]) out of all {B^[3], B^[4]} groups in the glass network, along with the fraction of B^[4]–O–Si linkages out of all B^[4]–O–Si/B bonds. Both parameters correlated linearly with the (average) CFS of the M⁺ and/or {M⁽²⁾⁺, Na⁺} cations. Both the nanoindentation-derived hardness and Young's modulus values of the glasses reduced upon their irradiation by Si²⁺ ions, with the property deterioration decreasing linearly with increasing M^z+ CFS, that is, for higher M^z+⋅⋅⋅O interaction strength. The irradiation damage of the glass network also increased linearly with the fraction of B^[4]–O–Si linkages, which are the second weakest in the structure after the M^z+⋅⋅⋅O bonds. Our results underscore the advantages of employing BS glasses with high-CFS cations for enhancing the radiation resistance for nuclear waste storage.     

The effect of position of ester group on critical micelle concentration of ester-linked sulfonates

The critical micelle concentration (CMC) of sodium alkyl sulfoacetates and β-sulfopropionates, and sodium salt of 2-sulfo ethyl ester, 3-sulfo propyl ester and 4-sulfo butyl ester of fatty acids have been determined by the electrical conductance of each aqueous solution. The relation between CMC value and number of total methylene groups (N) for the C_n ^*H_2n ^*+₁COO(CH₂)₃ SO₃Na and C₉H₁₉COO(CH₂)_n ^**SO₃Na (n^*=9, 10 and 11. n^**=2, 3 and 4) can be formulated as follows. $$\begin{gathered} \log {\text{CMC = - 0}}{\text{.293N + 1}}{\text{.778}} \hfill \\ {\text{for C}}_{\text{n}} *{\text{H}}_{{\text{2n}}} *_{ + ^1 } {\text{COO (CH2) 3SO3Na}} \hfill \\ {\text{log CMC = - 0}}{\text{.147 N + 0}}{\text{.011}} \hfill \\ {\text{for C9H19 COO (CH2) n **SO3Na}} \hfill \\ \end{gathered} $$ From these equations it was determined that the methylene unit situated between ester and sulfonate groups is equivalent to 0.5 methylene groups in its effect on CMC. For a given number of carbon atoms in the alkyl chain, the log CMC value increased regularly with a change in the ester group away from the terminal position to more central positions in the hydrocabon chain. The two different types of ester-linkages (RCOO-and ROCO-) have no apparent effect on the CMC value.     

Syntheses and Characterization of Diorganotin Derivatives of 2-Mercapto-5-methyl-1,3,4-thiadiazole: X-ray Crystal Structure of Polymeric (C3H3S2N2) [(n-C4H9)6Sn3O(OH)2](C3H3S2N2)

Diorganotin derivatives of 2-mercapto-5-methyl-1,3,4 -thiadiazole, (R = Me 1, n-Bu 2, Ph 3, PhCH₂ 4), have been synthesized and characterized by IR, ¹H, ¹³C and ¹¹⁹Sn NMR spectroscopy. Among them, polymer 2 was also characterized by X-ray crystallography diffraction analysis. This revealed that 2 showed a unique tricyclic structure consisting of a fused five-membered Sn₂ON₂ ring and a four-membered Sn₂O₂ ring. These formed a planar N₂Sn₃O₂ skeleton, with distorted trigonal bipyramidal coordination at the two tin centers and a distorted octahedral coordination at the other tin center. The supramolecular structure of polymer 2 was a 1D zig-zag polymeric chain stabilized by intermolecular O–H...S hydrogen bonds. An erratum to this article can be found at     

Influence of Al2O3/SiO2 ratio in multicomponent LNAS glasses and glass-ceramics on the crystallization behavior,microstructure and mechanical performance

Transparent glass-ceramics containing eucryptite and nepheline crystalline phases were prepared from alkali (Li, Na) aluminosilicate glasses with various mole substitutions of Al₂O₃ for SiO₂. The relationships between glass network structure and crystallization behavior of Li₂O–Na₂O–Al₂O₃–SiO₂ (LNAS) glasses were investigated. It was found that the crystallization of the eucryptite and nepheline in LNAS glasses significantly depended on the concentration of Al₂O₃. LNAS glasses with the addition of Al₂O₃ from 16 to 18 mol% exhibited increasing Q⁴ (mAl) structural units confirmed by NMR and Raman spectroscopy, which promoted the formation of eucryptite and nepheline crystalline phases. With the Al₂O₃ content increasing to 19–20 mol%, the formation of highly disordered (Li, Na)₃PO₄ phase which can serve as nucleation sites was inhibited and the crystallization mechanism of glass became surface crystallization. Glass-ceramics containing 18 mol% Al₂O₃ showed high transparency ～84% at 550 nm. Moreover, the microhardness, elastic modulus and fracture toughness are 8.56 GPa, 95.7 GPa and 0.78 MPa m^1/2 respectively. The transparent glass-ceramics with good mechanical properties show high potential in the applications of protective cover of displays.     

New host–guest supramolecular coordination polymers based on [(Me3Sn)3Fe(CN)6]n with alkali metal iodides and their applications as electrode materials in batteries

The metal iodides reduce partially the host coordination polymer of the type $ ^{ 3}_{\infty } \left[ {\left( {{\text{Me}}_{ 3} {\text{Sn}}} \right)_{ 3} {\text{Fe}}\left( {\text{CN}} \right)_{ 6} } \right] $ , I, to give new host–guest supramolecular coordination polymers (SCP). The physical and chemical characteristics of the new products were studied by elemental analyses, X-ray powder diffraction, IR, UV/Vis, and solid state NMR spectra. The host–guest SCP are [M_x(Me₃Sn)₃Fe_(1–x)^IIIFe _x ^II (CN)₆]_n M = Li⁺·2H₂O, 1; Li⁺, 2; Na⁺, 3; K⁺, 4; Cu⁺, 5, [Li(Me₃Sn)₃Fe^II(CN)₆]_n, 6 and [(LiDEE)_0.9(Me₃Sn)₃Fe _o.1 ^III Fe _o.9 ^II (CN)₆]_n, 7. The stoichiometry and nature of the guest depend on the type of the metal iodide and the reaction conditions. The polymeric nature of these SCP is due to the presence of trigonal bipyramidal configured structure which bridges between the single d-transition metal ions. The host–guest SCP containing the Li ions have been tested as electrodes to construct four different lithium-ion batteries.     

Theoretical studies of local structures and spin hamiltonian parameters for Cu<Superscript>2+</Superscript> in alkali barium borate glasses

The local structures and spin Hamiltonian parameters are theoretically studied for Cu²⁺ in alkali barium borate glasses 20A₂O ? 24.5BaO · 55B₂O₃ · 0.5CuO, where A = Li, Na and K by the quantitative calculations of these parameters for tetragonally elongated octahedral 3d ⁹ clusters. The [CuO₆]^10? clusters are subject to the local relative tetragonal elongation ratios 7.8, 8.1 and 8.4% in Li, Na and K barium borate glasses, respectively, owing to the Jahn–Teller effect. The increasing (Li < Na < K) local relative elongation ratio and decreasing cubic field parameter and covalency factor are discussed in a consistent way.     

Synthesis and characterization of a new 2D trimetallic Mn/Ca/Na complex

A new tri-metallic Mn/Ca/Na coordination polymer, {[Mn₃NaCa(sal)₆(H₂O)₆]·7H₂O}_n (1·7H₂O), has been synthesized and characterized by single crystal X-ray diffraction, IR spectroscopy, and magnetic measurements. The X-ray analysis shows 1 consists of a 2D homochiral (6,3) network with chiral [Mn₃Na] clusters and chiral Ca ions as alternating nodes. Magnetic property study reveals the existence of weak antiferromagnetic couplings between Mn(III) ions with the interaction parameter J being ? 0.438 cm^? 1 within the complex.     

Inter-conversion of 1-D coordination polymers in the Ce–Sr–dipicH2 system (dipicH2 = dipicolinic acid)

A solution of the previously known 1-D coordination polymer, made up of alternating [Ce(dipic)₃]²⁻ and [Sr(dipicH₂)(OH₂)₃]²⁺ polyhedra takes up additional Ce⁴⁺ and Sr²⁺ ions leading to the double stranded hetero-metallic squarate chain. The transformation can be reversed by adding excess dipicH₂. The crystal structure and thermal decomposition study of the new squarate chain polymer is reported. The analogous Ca compound does not undergo this transformation.     

Network of Bi2O3–Al2O3–NaPO3 glasses studied by solid-state nuclear magnetic resonance spectroscopy

A detailed structural investigation of a series of phosphate laser glasses with composition xBi₂O₃–yAl₂O₃–(100 − x–y)NaPO₃ (x = 0, 10; y = 0, 5, 10, 15, 20) has been conducted using solid-state nuclear magnetic resonance (NMR) techniques and X-ray photoelectron spectroscopy (XPS). ³¹P MAS NMR spectroscopy demonstrates that the addition of Bi₂O₃ and Al₂O₃ leads to the depolymerization of the phosphorus chain in the process of Q² → Q¹ → Q⁰. The various phosphorus species (Qⁿ, n = 0, 1, 2) are identified by ³¹P single pulse, ³¹P{²⁷Al} rotational echo adiabatic passage double resonance, ³¹P{²⁷Al} J-coupling-based heteronuclear multiple-quantum coherence, and 1D refocused INADEQUATE experiments. The results of ²³Na{³¹P}, ³¹P{²³Na}, ²⁷Al{³¹P} rotational echo double resonance, and XPS consistently confirm that Na⁺, Al³⁺, and Bi³⁺ ions are all bound by phosphorus tetrahedron [PO₄]³⁻. No bond is formed between these glass modifiers. Based on the complementary evidence from previous experiments, comprehensive local structure models are developed for these Bi₂O₃–Al₂O₃–NaPO₃ glasses.     

Characterization of the first hexacoordinate phosphorus compound with S→P←S bonds

The first example of a hexacoordinate phosphorus compound [S{6-t-Bu-4-Me-C₆H₂O}₂]₂P⁺(Cl^?·C₃H₄N₂) with two S→P bonds is reported. This compound can be construed as an oxophosphonium salt with double intramolecular coordination by sulfur atoms. X-ray structure reveals a facial arrangement of the ligands with two coordinating sulfur atoms cis to each other. The S→P distance of 2.334 (1) Å is one among very short coordinate bond distances between sulfur and phosphorus.     

Regulating Photocatalytic Selectivity of Anatase TiO2 with {101}, {001}, and {111} Facets

In this work, we demonstrate a novel approach to control the photocatalytic selectivity of TiO₂ though different dominant crystal facets. {101}, {111}, and {001} facets exposed nanoscale anatase TiO₂ were obtained by a simple hydrothermal route with different ratio of NH₄⁺ and F^?, then a calcined progress to clear surface adsorbent atoms. Results reveal that {101} exposed TiO₂ has some remain binding N with a mode of unsaturated N_3c exhibits selectively photocatalytic degradation of methylene orange (MO) in a methylene blue (MB) and methyl orange (MO) mixed solution, whereas TiO₂ with exposed {111} and {001} facets exhibits photocatalytic selectivity for MB. The {111} facets of anatase TiO₂ exhibit a better photocatalytic selective ability than {001} facets. It confirms that the photocatalytic selectivity can be affected by different dominant crystal facets. In a deeper analysis, there are many unsaturated O_2c on the surface of {001} and {111} facets, which enhances adsorbent selectivity and relevant photocatalytic activity of MB, at the same time, the unsaturated O_2c on the surface of {111} facets is much more than that on the surface of {001} facets results in a better photocatalytic selectivity of {111} facets. This research hopes that developing a new strategy for photocatalytic selectivity and providing a deeper understanding of different crystal facets of TiO₂.     

Synthesis, Crystal Structure and Antitumor Activity of Ca(II) Coordination Polymer Based on 1,5-Naphthalenedisulfonate

A novel Ca(II) coordination polymer, [CaL(H₂O)₂] _n (L = 1,5-naphthalenedisulfonate), was synthesized by reaction of calcium perchlorate with 1,5-naphthalenedisulfonic acid sodium in CH₃CH₂OH/H₂O. It was characterized by elemental analysis, IR, ¹HNMR and thermal analysis. X-ray crystallographic reveals that the Ca(II) coordination polymer belongs to triclinic system, with space group P-1. The geometry of the Ca(II) ion is a distorted CaO₆ octahedron coordination environment, arising from its coordination by two water molecules, and four oxygen atoms from two l ligands. The Ca(II) ions are linked through the O atoms of 1,5-naphthalenedisulfonate ligands to form 1D chain structure. And then a 2D layered structure is constructed by hydrogen bonds and π–π stacking. The antitumor activity of 1,5-naphthalenedisulfonic acid sodium ligand and its Ca(II) coordination polymer against human hepatoma smmc-7721 cell line and human lung adenocarcinoma A549 cell line have been investigated.     

Ionic Conductivity in Sodium–Alkaline Earth–Aluminosilicate Glasses

The effect of alkaline‐earth ions on Na transport in aluminosilicate glasses was studied by measuring ionic conductivity for a systematic compositional series of Na₂O–RO–Al₂O₃–SiO₂ glasses (R=Mg, Ca, Sr, Ba). The Na transport in aluminosilicate glass could be affected by compositional changes in aluminum coordination and nonbridging oxygen as well as physical properties such as dielectric constant, shear modulus, and ionic packing factor. Through careful experimental designs and measurements, the main determinants among these parameters were identified. ²⁷Al MAS‐NMR indicated that all aluminum species contained in these glasses are four‐coordinated. The activation energy for ion conductivity decreased with increasing aluminum content and decreasing ionic radii of the alkaline‐earth ion in the region where [Al] < [Na]. When the aluminum content exceeded the sodium content ([Al] > [Na]), the composition dependence of the activation energy depended on the specific alkaline earth. These results are explained based on variations in free volume and dielectric constant caused by structural changes around the AlO₄ charge compensation sites. These structure changes occur in response to the smaller size and higher field strength of the alkaline‐earth ions, and are most prevalent in the compositions which require bridging of two AlO₄ sites by the alkaline‐earth ion for charge compensation.     

Structure and Spectral Characteristics of 3D-Supramolecular Coordination Polymers Based on Copper Cyanide and Dimethylquinoxaline

The reactions of K₃[Cu(CN)₄], R₃SnCl (R = Me or ph) and 2,3-dimethyl quinoxaline (dmqox) in H₂O/acetonitrile media at room temperature afford the 3D-supramolecular coordination polymers (SCP) ³_￥ [ \textCu ₂ ( \textCN ) ₂ \textdmqox ] ^{ 3}_{\infty } \left[ {{\text{Cu}}_{ 2} \left( {\text{CN}} \right)_{ 2} {\text{dmqox}}} \right] , 1 and ³_￥ [ \textCu ₂ ( \textCN ) ₄ ·( \textPh ₃ \textSn ) ₂ ·\textdmqox ] ^{ 3}_{\infty } \left[ {{\text{Cu}}_{ 2} \left( {\text{CN}} \right)_{ 4} \cdot \left( {{\text{Ph}}_{ 3} {\text{Sn}}} \right)_{ 2} \cdot {\text{dmqox}}} \right] , 2. The structure of the tin free 1 consists of parallel zigzag chains connected by dmqox to form 2D-sheets containing hexagonal 18-atom fused Cu₆(CN)₄(dmqox)₂ rings. The interwoven sheets along the a axis are close packed by extensive H-bonds developing 3D-network structure. The structures of 1 and 2 are investigated by elemental analysis IR, NMR and mass spectra. The ESI⁺ and ESI⁻ mass spectra of 2 support its polymeric nature while the ESI⁺ mass spectrum confirms the expected M. W. suggested by elemental analysis. The ¹³C-NMR spectrum of 2 supports the fact that the network structure of 2 contains the rhombic [Cu₂(μ₃-CN)₂] motif. The structure of 2 was compared with the structure of the reported prototype ³_￥ [ \textCu ₂ ( \textCN ) ₄ ·( \textPh ₃ \textSn ) ₂ ·\textqox ] ^{ 3}_{\infty } \left[ {{\text{Cu}}_{ 2} \left( {\text{CN}} \right)_{ 4} \cdot \left( {{\text{Ph}}_{ 3} {\text{Sn}}} \right)_{ 2} \cdot {\text{qox}}} \right] as well as the other related structures.     

Hydrothermal synthesis,crystal structure and fluorescent properties of a novel 1D polymer: VO2(C7H3O4N)Ag(C10H8N2)·H2O

The hydrothermal synthesis of V₂O₅, AgNO₃, pyridine-2,6-dicarboxylic acid (H₂pdc) and 2,2′-bipyridine (bpy) in water at 160 °C for 4 days yields a novel 1D coordination polymer VO₂(C₇H₃O₄N)Ag(C₁₀H₈N₂)·H₂O (1). Each V center chelates to a tridentate ligand pdc^2? and coordinates to two O atoms, while the square based pyramid conformation of Ag center consists of three O atoms and a bpy molecular. V and Ag polyhedra alternate by either carboxyl or oxo bridges to further form a unique 3d–4d heterometal-based 1D double-chain ribbon.     

Low charge compensator (Mg2+) causing a new REE-end 3O structure (REE=Rare Earth Element) and a different phase transformation in Nd3+ Co-doped zirconolite: Investigation by X-ray structural analysis

Zirconolite-derived structures have shown promising applications for the immobilization of high-level radioactive wastes, especially for minor actinides. This study evaluated the effect of magnesium (Mg, one of the main impurities in natural zirconolites) incorporation into zirconolite on structural evolution and neodymium (Nd, surrogates to minor actinides) solubility in the designed zirconolite matrix. X-ray diffraction results showed the phase transformation from zirconolite-2M to zirconolite-3O with increasing Mg²⁺ incorporated into the target structure. The lattice parameters of zirconolites, Ca_(0.99-2x)Nd_2xZrTi_(2-x)Mg_xO₇, also showed a linear relationship with the amount of Mg²⁺ being substituted. The Rietveld refinement results showed that Nd³⁺ preferred occupying the Ca sites, while Mg²⁺ substituted the Ti sites in 5-fold coordination (TiO₅). X-ray adsorption near edge spectroscopy further revealed that the ratio of TiO₅ and TiO₆ in the zirconolites decreased and less distortions of TiO₆ polyhedra were induced with increasing Mg²⁺ concentration in the zirconolites. Moreover, a new mineral phase (REE-end zirconolite-3O) with the chemical formula of NdZrTi_1.5Mg_0.5O₇ was reported in this study, and the single target phase was synthesized without the coexistence of perovskite. The combination of selected area electronic diffraction and Rietveld refinement revealed that the structure of NdZrTi_1.5Mg_0.5O₇ was similar with zirconolite-3O - Nd dominated Ca in the 8-fold coordinated site, and Mg occupied the Ti sites in both 4-fold and 5-fold coordination. This study demonstrates that the new crystalline structure explored from the process of magnesium incorporation into zirconolites can provide insights about the design and optimization of reliable waste forms for the immobilization of nuclear wastes.     

Structure and disorder in Pb-Na metasilicate (PbO:Na2O:2SiO2) glasses: A view from high-resolution 17O solid-state NMR

Knowledge of the structure of lead (Pb)-bearing silicate glasses, such as degree of polymerization and arrangement among cations, provides improved prospects for understanding their macroscopic properties. Despite the importance, the detailed disorder in Pb-bearing silicate glasses with varying composition (i.e., Pb/alkali content) has not been systematically explored. Here, we reveal the first unambiguous structural information of PbO-Na₂O-SiO₂ glasses with varying PbO content [i.e., X_PbO = PbO/(Na₂O + PbO)], which are the fundamental model system for multicomponent Pb-bearing glasses, using high-resolution ¹⁷O solid-state NMR. ¹⁷O NMR spectra clearly show the resolved multiple oxygen sites, such as Na-O-Si, Si-O-Si, and [Na,Pb]-O-Si. As X_PbO increases, the fraction of [Na,Pb]-O-Si peak increases markedly at the expanse of substantial reduction in the fraction of Na-O-Si/total NBO. This trend indicates the relative predominance of the dissimilar pairs around non-bridging oxygen (NBO) and, therefore, can be explained well with the pronounced chemical ordering among Na⁺ and Pb²⁺. These results confirm that Pb is primarily a network-modifier in the glasses studied here. Atomic environments around both NBO and BO are affected by the change in Na/Pb ratio, while topological disorder due to cation mixing around NBO is much more prominent in Pb endmember. The structural details of short-range configurations around oxygen in alkali Pb-silicate glasses provide atomistic insights for understanding the properties of Pb-bearing multicomponent silicate glasses.     

Carbonato- and methanediolato(-2)-bridged nickel(II) coordination clusters from the use of N-salicylidene-4-methyl-o-aminophenol

The use of N-salicylidene-4-methyl-o-aminophenol in nickel(II) pivalate chemistry has provided access to structurally and magnetically interesting {Ni^II₆Na^I₄} and {Ni^II₆} clusters possessing carbonato and methanediolato(-2) ligands, respectively, with novel coordination modes.