J. Appl. Cryst.の発刊に際して

2.3. Evaluation of Photocatalytic Water Splitting 6507 2.3.1. Photocatalytic Activity 6507 2.3.2. Photocatalytic Stability 6507 3. UV-Active Photocatalysts for Water Splitting 6507 3.1. d0 Metal Oxide Photocatalyts 6507 3.1.1. Ti-, Zr-Based Oxides 6507 3.1.2. Nb-, Ta-Based Oxides 6514 3.1.3. W-, Mo-Based Oxides 6517 3.1.4. Other d0 Metal Oxides 6518 3.2. d10 Metal Oxide Photocatalyts 6518 3.3. f0 Metal Oxide Photocatalysts 6518 3.4. Nonoxide Photocatalysts 6518 4. Approaches to Modifying the Electronic Band Structure for Visible-Light Harvesting 6519

Semiconductor-based Photocatalytic Hydrogen Generation

介绍了Kirk—Othmer Encyclopedia of Chemical Technology（化工技术百科全书）（第五版）电子图书网络版数据库，并对该数据库使用方法和检索途径作出了说明，且结合实例简单地介绍了该数据库的检索方法。

Kirk-Othmer Encyclopedia of Chemical Technology数据库介绍及实例

We have recently described a remarkable new way of exploring packing modes and intermolecular interactions in molecular crystals using a novel partitioning of crystal space. These molecular Hirshfeld surfaces reflect intermolecular interactions in a novel visual manner, offering a hitherto unseen picture of molecular shape in a crystalline environment. The surfaces encode information about all intermolecular interactions simultaneously, but sophisticated interactive graphics are required in order to extract the information most efficiently. To overcome this we have devised a two-dimensional mapping which summarizes quantitatively the nature and type of intermolecular interaction experienced by a molecule in the bulk, and presents it in a convenient graphical format. The mapping takes advantage of the triangulation of the Hirshfeld surfaces, and plots the fraction of points on the surface as a function of the closest distances from the point to nuclei inside and outside the surface.
In this manner all interaction types (for example, hydrogen bonding, close and distant van der Waals contacts, C–H⋯π interactions, π–π stacking) are readily identifiable, and it becomes a straightforward matter to classify molecular crystals by the nature of interactions, and to rapidly identify similarities and differences which can become obscured when examining crystal packing diagrams. These plots are a novel visual representation of all the intermolecular interactions simultaneously, and are unique for a given crystal structure and polymorph. Applications to a wide variety of molecular crystals and intermolecular interactions are presented, including polymorphic systems, as well as crystals where Z′ > 1.

Fingerprinting intermolecular interactions in molecular crystals

The halogen bond occurs when there is evidence of a net attractive interaction between an electrophilic region associated with a halogen atom in a molecular entity and a nucleophilic region in another, or the same, molecular entity. In this fairly extensive review, after a brief history of the interaction, we will provide the reader with a snapshot of where the research on the halogen bond is now, and, perhaps, where it is going. The specific advantages brought up by a design based on the use of the halogen bond will be demonstrated in quite different fields spanning from material sciences to biomolecular recognition and drug design.

The Halogen Bond

The crystal structure of NaBi3V2O10 has been determined using the ab initio approach followed by Rietveld refinement via powder X-ray diffraction. The unit cell is triclinic, space group P1, with a = 7.1964(4) A, b = 7.0367(3) A, c = 5.5139(2) A, α = 84.440(3)°, β = 113.461(2)°, γ =112.319(2)°, and V =236.46(2) A3. The final refinements gave Rp = 9.94%, Rwp = 13.11%, and R(I,hkl) = 8.73% for 30 parameters and 4871 data points. These results indicate that this is a polymorph different from that reported previously and represents a new class of oxide ion conductors in solid solution of the Na2O−Bi2O3−V2O5 ternary system. The (Bi2O2)2+ chains extend along the c axis with VO4 units joining the chains along both a and b directions resulting in a hitherto unknown motif in this class of compounds. The structure hence points to a new mode for the mechanism of oxide ion conduction.

A Novel Oxide Ion Conductor in a Doped Bi2O3-V2O5 System: Ab Initio Structure of a New Polymorph of NaBi3V2O10 via Powder X-ray Diffraction†

Mechanistics of stabilisation via doping in bismuthsesquioxide (Bi2−2xHo2xO3; x=0.2): A combined approach of Rietveld and microstructural analysis

Structure and superconducting properties of Tl 1− y Pb y Y 1− x Ca x Sr 2 Cu 2 O 7 ( y =0.0, 0.1, 0.25 and 0.5) , derived from the parent insulator TlYSr 2 Cu 2 O 7 , have been investigated for different values of x . XANES studies show Pb to be in the 4+ state while Tl is in the 3+ state, suggesting thereby that in this series, ( x − y ) approximately corresponds to the hole concentration. The in-plane CuO distance decreases with increase in x for all values of y . The apical CuO distance as well as the Tl(Pb)O(2) distance show anomalies at x =0.5 in the series with y =0.25; at this composition, T c also reaches a maximum. In general, the composition (value of x ) at which the T c of Tl 1− y Pb y Y 1− x Ca x Sr 2 Cu 2 O 7 reaches a maximum depends on the Pb content and the maximum T c itself increases with increase in y , reaching a value of 105 K at y =0.5. More interestingly, a maximum T c occurs at an ( x − y ) value of ∼0.25, which is close to the hole concentration at maximum T c in other cuprate superconductors containing two CuO 2 layers.

Structure and superconducting properties of Tl1-yPbyY1-xCaxSr2Cu2O7

A new ternary interstitial nitride Ni2W3N has been synthesized by the ammonolysis of different oxide precursors and characterized by powder X-ray diffraction and electron microscopy. This nitride crystallizes in the cubic space group P4132 (213) [Ni2W3N, a=6.663(1) A, Z=4] and is isostructural with Al2Mo3C. This compound belongs to the rare class of intermetallic ternary nitrides and carbides crystallizing with a filled β-Mn structure. Ni2W3N is not stable, it decomposes to a new compound NiW3N related to the distorted anti-perovskite, Ca3AsN structure.

Synthesis, structure and properties of a new ternary interstitial nitride: ni2w3n

In the title 2:1 salt, 2C(2)H(6)NO(2)(+)center dot C2O42-, the glycine mol-ecule is in the cationic form with a positively charged amino group and an uncharged carboxylic acid group. The doubly charged oxalate anion lies across a crystallographic inversion centre. One of the reasons why the 1:1 glycinium oxalate salt has a higher melting point than the title compound may be the difference in their hydrogen-bonding patterns. A database search for salts formed between amino acids or substituted amino acids and oxalic acid revealed that, in most of the structures, the conformation about the O=C-OH bond is synplanar. D-Tryptophan oxalate is the only example where the OH group of a semi-oxalate adopts an anti-planar conformation. The 2:1 stoichiometry seen in the present salt is observed only in the salts of DL-serine, DL-aspartic acid and betaine with oxalic acid.

T. N. Guru Row

Papers

A Novel Oxide Ion Conductor in a Doped Bi2O3-V2O5 System: Ab Initio Structure of a New Polymorph of NaBi3V2O10 via Powder X-ray Diffraction†

Mechanistics of stabilisation via doping in bismuthsesquioxide (Bi2−2xHo2xO3; x=0.2): A combined approach of Rietveld and microstructural analysis

Structure and superconducting properties of Tl1-yPbyY1-xCaxSr2Cu2O7

Synthesis, structure and properties of a new ternary interstitial nitride: ni2w3n

Bis(glycinium) oxalate : evidence of strong hydrogen bonding