2,089 publications from this institution
A reexamination of the thermally induced phase transitions of CsHSO4 shows that the room-temperature phase IV transforms to II around 373 K. Phase III is, however, not obtained by heating IV to 340 K. Phases IV and III can coexist at room temperature under certain conditions; and phase III appears to transform to II at 340 K.
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.
By employing tributylphosphate as the source of phosphorus, several open-framework zinc and cobalt phosphates have been prepared hydrothermally. Of the three new zinc phosphates [C6N2H18][Zn(HPO4)2], I, has a linear chain structure while [C4N2H14][Zn5(PO4)4(H2O)], II, [NH4][H3O][Zn4(PO4)3]2·H2O, III, have three-dimensional structures. Of the three new cobalt phosphates described, [C5N2H14][Co(HPO4)2], IV, and [C5N2H14][Co(HPO4)2], V, have linear chain structures, while [C4N2H12]3 [Co2(OH)(HPO4)3]2, VI, has a complex double chain structure. The study shows that the use of the organophosphate yields a variety of architectures of metal phosphates.
Giant magnetoresistance, and spin‐, charge‐, and orbital‐ordering are some of the properties displayed by manganates that make these materials of interest in magnetic recording, sensor, and actuator technology. New and significant results on the giant magnetoresistance found in films as well as polycrystalline and single‐crystal samples of rare earth manganates are reviewed along with related aspects. The unique features of these systems and the as‐yet unsolved problems are highlighted. Charge‐ordering as opposed to spin‐ordering is also discussed and suggestions for future directions are given.
No abstract is provided for this article.
The high-resolution electron microscopic technique of lattice imaging shows 15 and 3 AA repeat sequences in 6H SiC. The 15 AA sequence is further resolved into 2.5 AA layers corresponding to the interlayer separation.
No abstract is provided for this article.
Nanoparticles and nanoplatelets of WO3 and nanowires of WO2.72 have been investigated for their H2S-sensing characteristics over the 1–1000ppm concentration range at 40–250°C. The nanoparticles and nanoplatelets of WO3 exhibit response values of 757 and 1852, respectively to 1000ppm H2S at 250°C, respectively, compared to the response of 3313 of the nanowires of WO2.72. Interestingly, the response of the nanowires is satisfactory (121) to 10ppm H2S at 250°C, while a large response (240) is observed to 1000ppm H2S even at 40°C. The WO2.72 nanowires emerge as a good candidate for H2S sensors, with little effect of humidity up to 60% relative humidity as well as satisfactory response and recovery times.
A layered aluminum phosphate, I, [C2N2H10][Al2(OH)2H2O(PO4)2]H2O, with Al:P ratio of 1:1 has been prepared using a novel synthetic route wherein the amine phosphate, [C2N2H10][HPO4], was reacted with Al3+ ions under hydrothermal conditions. I crystallizes in the triclinic space group P(−1) (No. 2); a=6.614(1), b=9.918(1), c=10.381(1) Å, α=115.3(1), β=90.2(1), γ=90.8(1)°; V=615.6(2) Å3; Z=2, D calc=2.029 gcm−3; μ (MoKα)=0.565 mm−1. The final R=0.07 and wR 2=0.17 and S=1.15 have been obtained for 198 parameters. The layered structure of I has Al both in trigonal bi-pyramidal and octahedral coordinations and the polyhedra are so connected as to give rise to 3-membered Al2P rings and infinite Al–O(H)–Al linkages. The structure is closely related to the mineral tancoite.
For Abstract see ChemInform Abstract in Full Text.
Nanocrystals of semiconductors as well as of metals covered by alkanethiols organize themselves in two-dimensional arrays. We discuss such arrays of metal nanocrystals at length, with our focus on the dependence of the structure and stability of the arrays on the particle diameter and the distance between the particles. Three-dimensional superstructures of metal nanocrystals obtained by the use of alkanedithiols are examined. These ordered two-and three-dimensional structures of thiolized metal nanocrystals are good examples of mesoscale self-assembly. The association of metal nanocrystals to give rise to giant clusters with magic nuclearity provides an even more graphic demonstration of mesoscale self-assembly.
