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John B Parise

Publications and source records attributed to John B Parise.

15 recordsLinked to original sources
PubMed2006

Adsorption of molecular hydrogen on coordinatively unsaturated Ni(II) sites in a nanoporous hybrid material.

A porous hybrid inorganic/organic material, NaNi3(OH)(SIP)2 [SIP = 5-sulfoisophthalate][1], is shown to strongly bind molecular hydrogen at coordinatively unsaturated metal sites. A combination of H2 sorption isotherms, temperature programmed desorption, and inelastic neutron scattering spectroscopy show the existence of a considerable number of such strong binding sites in [1] along with other sites where hydrogen is more weakly physisorbed. The overall capacity for hydrogen of this material as well as the much stronger binding of hydrogen than in typical porous material represent an important step toward a possible utilization of porous media for hydrogen storage.

Adsorption↗
PubMed2006

Characterization and surface reactivity of ferrihydrite nanoparticles assembled in ferritin.

Ferrihydrite nanoparticles with nominal sizes of 3 and 6 nm were assembled within ferritin, an iron storage protein. The crystallinity and structure of the nanoparticles (after removal of the protein shell) were evaluated by high-resolution transmission electron microscopy (HRTEM), atomic force microscopy (AFM), and scanning tunneling microscopy (STM). HRTEM showed that amorphous and crystalline nanoparticles were copresent, and the degree of crystallinity improved with increasing size of the particles. The dominant phase of the crystalline nanoparticles was ferrihydrite. Morphology and electronic structure of the nanoparticles were characterized by AFM and STM. Scanning tunneling spectroscopy (STS) measurements suggested that the band gap associated with the 6 nm particles was larger than the band gap associated with the 3 nm particles. Interaction of SO2(g) with the nanoparticles was investigated by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, and results were interpreted with the aid of molecular orbital/density functional theory (MO/DFT) frequency calculations. Reaction of SO2(g) with the nanoparticles resulted primarily in SO(3)2- surface species. The concentration of SO3(2-) appeared to be dependent on the ferrihydrite particle size (or differences in structural properties).

Ferric Compounds↗
PubMed2006

Solid-state structural characterization of a rigid framework of lacunary heteropolyniobates.

In our ongoing investigations of heteropolyniobate chemistry, a phase featuring decorated, A-type trivacant alpha-Keggin ions linked by their charge-balancing sodium cations has been isolated and structurally characterized. This is the first heteropolyniobate reported that has a true lacunary structure type. Na15[(PO2)3PNb9O34] x 22 H2O (1) [triclinic space group P1 (No. 2); a = 12.242 (2) A, b = 12.291 (3) A, c = 22.056 (4) A; alpha = 93.12 (3) degrees, beta = 99.78 (3) degrees, gamma = 119.84 (3) degrees; Z = 4, V = 2799.2 (10) A3] is composed of bilayers of the heteropolyanions alternating with layers of hydrated Na+ cations. Sodium cations also bridge the clusters within their layers through Na-O(t)-Nb, Na-O(b)-Nb2, and Na-O(t)-P bonds (t = terminal and b = bridging). This phase is poorly soluble in water, suggesting that it is more characteristic of a framework of linked heteropolyanions rather than a water-soluble heteropolyanion salt. Two-dimensional solid-state 23Na multiple-quantum magic angle spinning (MAS) NMR of 1 reveals five distinctive chemical and structural environments for sodium, which agrees with the crystallographic data. The 23Na and 1H MAS NMR studies further illustrate the rigid and immobile nature of this framework of cations and anions.

Journal Article↗
PubMed2006

Structural disorder of a new zeolite-like lithosilicate, K(2.6)Li(5.4)[Li4Si16O38].4.3H2O.

The framework structure of the synthetic microporous lithosilicate RUB-30 (K(2.6)Li(5.4)[Li4Si16O38].4.3H2O) is similar to that of the fibrous zeolites such as natrolite, edingtonite and thomsonite, since all their frameworks include the same secondary structural building unit, the so-called 4-1 T5O10 cluster of tetrahedra. Unique to the structure of RUB-30, each 4-1 unit consists of a LiSi4O10 moiety within which the single [LiO4] tetrahedron is strictly segregated from the other four [SiO4] tetrahedra. The connection of neighboring 4-1 units through edge-sharing [LiO4] tetrahedra results in a new framework topology. The present work reports an ;average' structure of RUB-30 solved by synchrotron X-ray single-crystal diffraction data collected at a second-generation source. A superstructure with a x 2b x c (relative to the subcell quoted above) could be seen in X-ray diffraction data collected with better resolution and higher brightness at a third generation source. Diffuse streaks along k with l = odd and unusual superstructure hkl reflections, with k = odd and l = odd only, indicate a more complicated real structure of the material. To explain this observation we propose two different structure types which are statistically, but coherently, intergrown in RUB-30.

Journal Article↗
PubMed2005

Tribasic lead maleate and lead maleate: synthesis and structural and spectroscopic characterizations.

We report on the synthesis and structure of tribasic lead maleate hemihydrate ([Pb4O3]C2H2(CO2)2.(1/2)H2O, TRIMAL) and lead maleate (PbC2H2(CO2)2, PBMAL). The structure of [Pb4O3]C2H2(CO2)2.(1/2)H2O, solved ab initio from X-ray powder diffraction data, consists of infinite slabs of edge-sharing OPb4 tetrahedra, of composition [Pb4O3], running along the c axis and linked together into a three-dimensional network by tetradentate maleate anionic ligands. The structure of PbC2H2(CO2)2, solved from single crystal diffraction data, is lamellar and contains double layers of heptacoordinated lead atoms, bonded only to the oxygen atoms of the maleate ligands. In both compounds, lead is in the oxidation state 2+ and the coordination polyhedra around the Pb2+ exhibit a hemidirected geometry and are strongly distorted as a result of the lone pair of electrons. The absence of protons on the acidic portion of the maleate moieties was confirmed by Raman spectroscopy and by 1H MAS and 1H-13C CP MAS NMR experiments. The two compounds were further characterized using chemical and thermogravimetric analyses.

Journal Article↗
PubMed2005

High-pressure neutron diffraction study of superhydrated natrolite.

Neutron powder diffraction data were collected on a sample of natrolite and a 1:1 (v/v) mixture of perdeuterated methanol and water at a pressure of 1.87(11) GPa. The natrolite sample was superhydrated, with a water content double that observed at ambient pressure. All of the water deuterium atoms were located and the nature and extent of the hydrogen bonding elucidated for the first time. This has allowed the calculation of bond valence sums for the water oxygen atoms, and from this, it can be deduced that the key energetic factor leading to loss of the additional water molecule upon pressure release is the poor coordination to sodium cations within the pores.

Journal Article↗
PubMed2005

Quantitative high-pressure pair distribution function analysis.

The collection of scattering data at high pressure and temperature is now relatively straightforward thanks to developments at high-brightness synchrotron radiation facilities. Reliable data from powders, that are suitable for structure determination and Rietveld refinement, are routinely collected up to about 30 GPa in either a large-volume high-pressure apparatus or diamond anvil cell. In those cases where the total elastic scattering is of interest, as it is in the case of nano-crystalline and glassy materials, technical developments, including the use of focused high-energy X-rays (>80 keV), are advantageous. Recently completed experiments on nano-crystalline materials at the 1-ID beamline at the Advanced Photon Source suggest that quantitative data, suitable for pair distribution function analysis, can be obtained.

Journal Article↗
PubMed2005

Short- and long-range order in the positive electrode material, Li(NiMn)0.5O2: a joint X-ray and neutron diffraction, pair distribution function analysis and NMR study.

The local environments and short-range ordering of LiNi(0.5)Mn(0.5)O(2), a potential Li-ion battery positive electrode material, were investigated by using a combination of X-ray and neutron diffraction and isotopic substitution (NDIS) techniques, (6)Li Magic Angle Spinning (MAS) NMR spectroscopy, and for the first time, X-ray and neutron Pair Distribution Function (PDF) analysis, associated with Reverse Monte Carlo (RMC) calculations. Three samples were studied: (6)Li(NiMn)(0.5)O(2), (7)Li(NiMn)(0.5)O(2), and (7)Li(NiMn)(0.5)O(2) enriched with (62)Ni (denoted as (7)Li(ZERO)Ni(0.5)Mn(0.5)O(2)), so that the resulting scattering length of Ni atoms is null. LiNi(0.5)Mn(0.5)O(2) adopts the LiCoO(2) structure (space group Rm) and comprises separate lithium layers, transition metal layers (Ni, Mn), and oxygen layers. NMR experiments and Rietveld refinements show that there is approximately 10% of Ni/Li site exchange between the Li and transition metal layers. PDF analysis of the neutron data revealed considerable local distortions in the layers that were not captured in the Rietveld refinements performed using the Bragg diffraction data and the LiCoO(2) structure, resulting in different M-O bond lengths of 1.93 and 2.07 Angstroms for Mn-O and Ni/Li-O, respectively. Large clusters of 2400-3456 atoms were built to investigate cation ordering. The RMC method was then used to improve the fit between the calculated model and experimental PDF data. Both NMR and RMC results were consistent with a nonrandom distribution of Ni, Mn, and Li cations in the transition metal layers; both the Ni and Li atoms are, on average, close to more Mn ions than predicted based on a random distribution of these ions in the transition metal layers. Constraints from both experimental methods showed the presence of short-range order in the transition metal layers comprising LiMn(6) and LiMn(5)Ni clusters combined with Ni and Mn contacts resembling those found in the so-called "flower structure" or structures derived from ordered honeycomb arrays.

Journal Article↗
PubMed2004

Polymorphism in NaSbO3: structure and bonding in metal oxides.

A new polymorph of NaSbO(3) has been synthesized at 10.5 GPa and 1150 degrees C in a uniaxial split sphere anvil type press (USSA-2000) and recovered back to ambient conditions. The high-pressure form of NaSbO(3) adopts an orthorhombically distorted perovskite structure, isostructural with CaTiO(3), GdFeO(3), and NaTaO(3). The space group is Pnma, and the unit cell dimensions are a = 5.43835(6) A, b = 7.66195(8) A, c = 5.38201(5) A. It is a white insulator with an optical band gap of 3.4 eV. This compound represents the first ternary perovskite prepared containing Sb(5+) on the octahedral site. The octahedral tilting distortion in this compound is much larger than expected from ionic radii considerations. The distortion is driven by a second-order Jahn-Teller distortion originating on oxygen that can be traced back to strong Sb-O covalent bonding. A conflict arises between the strong covalent bonding interactions at oxygen that favor a large octahedral tilting distortion and the repulsive Na-O interactions that oppose excessive octahedral tilting. This conflict destabilizes the perovskite topology, thereby stabilizing the ilmenite polymorph under ambient conditions. Analysis of ionic and covalent bonding explains why ASbO(3) and ABiO(3) compositions frequently adopt structures that violate Pauling's rules.

Journal Article↗
PubMed2003

Cs[Si(3)O(6)(OH)] and Rb[Si(2)O(4)(OH)]: two novel phyllosilicates.

The crystal structures of two novel phyllosilicates with compositions Cs[Si(3)O(6)(OH)] (caesium hydroxohexaoxotetraotrisilicate) and Rb[Si(2)O(4)(OH)] (rubidium hydroxohexaoxotetraodisilicate) have been characterized by X-ray diffraction. The topology of the caesium phyllosilicate silica sheet consists of interconnected four- and six-membered rings and thus differs from all of the previously reported phyllosilicates. The topology of the rubidium phyllosilicate silica sheet consists of six-membered rings only, in boat conformations, resulting in a corrugated sheet similar to that observed in delta-Na(2)Si(2)O(5). Both of the title compounds exhibit the characteristic sandwich structure of sheet silicates, with the Cs atom ninefold coordinated and the Rb atom eightfold coordinated to the framework O atoms.

Journal Article↗
PubMed2003

(K4Li4)Al8Ge8O32.8H2O: an Li+-exchanged potassium aluminogermanate with the zeolite gismondine (GIS) topology.

The title compound, lithium potassium dialuminium digermanium octaoxide dihydrate, (K,Li)-(Al,Ge)-GIS (GIS is gismondine), is the result of a 50% Li(+) exchange into the K-(Al,Ge)-GIS structure. The (K,Li)-(Al,Ge)-GIS structure was determined from a 4 x 4 x 2 micro m octahedral single crystal at the ESRF synchrotron X-ray source. The ion exchange results in a symmetry transformation from I2/a for K-(Al,Ge)-GIS to C2/c for (K,Li)-(Al,Ge)-GIS. The structural change is due to disordering of K(+) ions with Li(+) ions along the [001] channel and ordering of water molecules in the [101] channels. The distance between sites partially occupied by K(+) ions increases from 2.19 (3) A in K-(Al,Ge)-GIS to 2.94 (3) A in (K,Li)-(Al,Ge)-GIS. The Li(+) ions occupy positions along the twofold axis at the intersection of the eight-membered-ring channels in a twofold coordination with water molecules. For the four closest framework O(2-) anions, the Li.O distances are 3.87 (4) A.

Journal Article↗
PubMed2002

Non-framework cation migration and irreversible pressure-induced hydration in a zeolite.

Zeolites crystallize in a variety of three-dimensional structures in which oxygen atoms are shared between tetrahedra containing silicon and/or aluminium, thus yielding negatively charged tetrahedral frameworks that enclose cavities and pores of molecular dimensions occupied by charge-balancing metal cations and water molecules. Cation migration in the pores and changes in water content associated with concomitant relaxation of the framework have been observed in numerous variable-temperature studies, whereas the effects of hydrostatic pressure on the structure and properties of zeolites are less well explored. The zeolite sodium aluminosilicate natrolite was recently shown to undergo a volume expansion at pressures above 1.2 GPa as a result of reversible pressure-induced hydration; in contrast, a synthetic analogue, potassium gallosilicate natrolite, exhibited irreversible pressure-induced hydration with retention of the high-pressure phase at ambient conditions. Here we report the structure of the high-pressure recovered phase and contrast it with the high-pressure phase of the sodium aluminosilicate natrolite. Our findings show that the irreversible hydration behaviour is associated with a pronounced rearrangement of the non-framework metal ions, thus emphasizing that they can clearly have an important role in mediating the overall properties of zeolites.

Journal Article↗
PubMed2002

Pressure-induced volume expansion of zeolites in the natrolite family.

Powder diffraction patterns of the zeolites natrolite (Na(16)Al(16)Si(24)O(80).16H(2)O), mesolite (Na(5.33)Ca(5.33)Al(16)Si(24)O(80).21.33H(2)O), scolecite (Ca(8)Al(16)Si(24)O(80).24H(2)O), and a gallosilicate analogue of natrolite (K(16)Ga(16)Si(24)O(80).12H(2)O), all crystallizing with a natrolite framework topology, were measured as a function of pressure up to 5.0 GPa with use of a diamond-anvil cell and a 200 microm focused monochromatic synchrotron X-ray beam. Under the hydrostatic conditions mediated by an alcohol and water mixture, all these materials showed an abrupt volume expansion (ca. 2.5% in natrolite) between 0.8 and 1.5 GPa without altering the framework topology. Rietveld refinements using the data collected on natrolite show that the anomalous swelling is due to the selective sorption of water from the pressure-transmission fluid expanding the channels along the a- and b-unit cell axes. This gives rise to a "superhydrated" phase of natrolite with an approximate formula of Na(16)Al(16)Si(24)O(80).32H(2)O, which contains hydrogen-bonded helical water nanotubes along the channels. In mesolite, which at ambient pressure is composed of ordered layers of sodium- and calcium-containing channels in a 1:2 ratio along the b-axis, this anomalous swelling is accompanied by a loss of the superlattice reflections (b(mesolite) = 3b(natrolite)). This suggests a pressure-induced order-disorder transition involving the motions of sodium and calcium cations either through cross-channel diffusion or within the respective channels. The powder diffraction data of scolecite, a monoclinic analogue of natrolite where all sodium cations are substituted by calcium and water molecules, reveal a reversible pressure-induced partial amorphization under hydrostatic conditions. Unlike the 2-dimensional swelling observed in natrolite and mesolite, the volume expansion of the potassium gallosilicate natrolite is 3-dimensional and includes the lengthening of the channel axis. In addition, the expanded phase, stable at high pressure, is retained at ambient conditions after pressure is released. The unprecedented and intriguing high-pressure crystal chemistry of zeolites with the natrolite framework topology is discussed here relating the different types of volume expansion to superhydration.

Journal Article↗
PubMed2002

Sandia octahedral molecular sieves (SOMS): structural and property effects of charge-balancing the M(IV)-substituted (M = Ti, Zr) Niobate framework.

Sandia octahedral molecular sieves (SOMS) is an isostructural, variable composition class of ion exchangers with the general formula Na(2)Nb(2-x)M(IV)(x)O (6-x)(OH)(x).H(2)O (M(IV) = Ti, Zr; x = 0.04-0.40) where up to 20% of the framework Nb(V) can be substituted with Ti(IV) or Zr(IV). This class of molecular sieves is easily converted to perovskite through low-temperature heat treatment (500-600 degrees C). This report provides a detailed account of how the charge imbalance of this Nb(V)-M(IV) substitution is compensated. X-ray powder diffraction with Rietveld refinement, infrared spectroscopy, thermogravimetric analysis, (23)Na MAS NMR, and (1)H MAS NMR were used to determine how the framework anionic charge is cation-balanced over a range of framework compositions. All spectroscopic evidence indicated a proton addition for each M(IV) substitution. Evidences for variable proton content included (1) increasing OH observed by (1)H MAS NMR with increasing M(IV) substitution, (2) increased infrared band broadening indicating increased H-bonding with increasing M(IV) substitution, (3) increased TGA weight loss (due to increased OH content) with increasing M(IV) substitution, (4) no variance in population on the sodium sites (indicated by Rietveld refinement) with variable composition, and (5) no change in the (23)Na MAS NMR spectra with variable composition. Also observed by infrared spectroscopy and (23)Na MAS NMR was increased disorder on the Nb(V)/M(IV) framework sites with increasing M(IV) substitution, evidenced by broadening of these spectral features. These spectroscopic studies, along with ion exchange experiments, also revealed the effect of the Nb(V)/M(IV) framework substitution on materials properties. Namely, the temperature of conversion to NaNb(1-x)M(IV)(x)O(3) (M = Ti, Zr) perovskite increased with increasing Ti in the framework and decreased with increasing Zr in the framework. This suggested that Ti stabilizes the SOMS framework and Zr destabilizes the SOMS framework. Finally, comparing ion exchange properties of a SOMS material with minimal (2%) Ti to a SOMS material with maximum (20%) Ti revealed the divalent cation selectivity of these materials which was reported previously is a function of the M(IV) substitution in the framework. A thorough investigation of this class of SOMS materials has revealed the importance of understanding the influence of heterovalent substitutions in microporous frameworks on material properties.

Journal Article↗