ß-V2O5 as Magnesium Intercalation Cathode.

Magnesium batteries have attracted great attention as an alternative to Li-ion batteries but still suffer from limited choice of positive electrode materials. V2O5 exhibits high theoretical capacities, but previous studies have been mostly limited to α-V2O5. Herein, we report on the ß-V2O5 polymorph as a Mg intercalation electrode. The structural changes associated with the Mg2+ (de-) intercalation were analyzed by a combination of several characterization techniques: in situ high resolution X-ray diffraction, scanning transmission electron microscopy, electron energy-loss spectroscopy, and X-ray absorption spectroscopy. The reversible capacity reached 361 mAh g-1, the highest value found at room temperature for V2O5 polymorphs.

Controllable Nonclassical Conductance Switching in Nanoscale Phase-Separated (PbI2 )1- x (BiI3 )x Layered Crystals.

Layered 2D (PbI2 )1- x (BiI3 )x materials exhibit a nonlinear dependence in structural and charge transport properties unanticipated from the combination of PbI2 and BiI3 . Within (PbI2 )1- x (BiI3 )x crystals, phase integration yields deceptive structural features, while phase boundary separation leads to new conductance switching behavior observed as large peaks in current during current-voltage (I-V) measurements (±100 V). Temperature- and time-dependent electrical measurements demonstrate that the behavior is attributed to ionic transport perpendicular to the layers. High-resolution transmission electron microscopy reveals that the structure of (PbI2 )1- x (BiI3 )x is a "brick wall" consisting of two phases, Pb-rich and Bi-rich. These brick-like features are 10s nm a side and it is posited that iodide ion transport at the interfaces of these regions is responsible for the conductance switching action.

AuPb2I7: A Narrow Bandgap Au3+ Iodide Semiconductor.

The unusual Au3+ ternary halide AuPb2I7 has been isolated from reactions of AuI, PbI2, and I2. AuPb2I7 crystallizes in the triclinic P1̅ space group as micron-scale needles with cell dimensions a = 4.5170(3) Å, b = 7.3847(4) Å, c = 12.2970(7) Å, α = 76.374(4)°, ß = 83.711(4)°, γ = 72.987(3)° at room temperature with ρ = 6.538 g/cm3 and has no structural phase transition down to 100 K. The title compound has a unique three-dimensional structure composed of [Pb2I7]3- pseudolayers extending in [010] bridged by square planar Au3+ at an oblique angle in the [001] direction. The pseudolayers are composed of 1/∞[Pb2I2]2+ chains propagating down [100] linked by square planar I- ions through [010]. AuPb2I7 has a bandgap of 1.17 eV and is stable in air for several days, before degrading to PbI2, Au0, and I2. Density functional theory calculations show that AuPb2I7 is an indirect bandgap semiconductor where the bandgap stems predominantly from Au-I metal-ligand charge transfer.

Bis(1-ethyl-3-methyl-imidazolium) 3,6-diselanyl-idene-1,2,4,5-tetra-selena-3,6-diphospha-cyclo-hexane-3,6-di-selen-olate.

In the title compound, 2C6H11N2 (+)·P2Se8 (2-) or [EMIM]2P2Se8 (EMIM = 1-ethyl-3-methyl-imidazolium), the anions, located about inversion centers between EMIM cations, exhibit a cyclo-hexane-like chair conformation. The cations are found in columns along the a axis, with centroid-centroid distances of 3.8399 (3) and 4.7530 (2) Å. The observed P-Se distances and Se-P-Se angles agree with other salts of this anion.

Ionothermal synthesis of four new nickel thiophosphate anions: [Ni(P2S8)2]2­, [Ni(P3S9)(P2S8)]3­, [Ni(P3S9)2]4­, and [(NiP3S8)4(PS4)]7­.

Four new nickel thiophosphate anions have been isolated as 1-ethyl-3-methylimidazolium (EMIM) salts: [EMIM](2)[Ni(P(2)S(8))(2)] (1), [EMIM](3)[Ni(P(3)S(9))(P(2)S(8))] (2), [EMIM](4)[Ni(P(3)S(9))(2)] (3), and [EMIM](7)[(NiP(3)S(8))(4)(PS(4))] (4). Single crystals of each were prepared by ionothermal reaction of the elements in [EMIM][BF(4)]. 1 can also be obtained from [EMIM][CF(3)SO(3)]. In all four anions, Ni atoms are octahedrally coordinated and P atoms are tetrahedrally coordinated. In the anion found in 1, two tridentate 1,3-P(2)S(8)(2-) ligands are cis to each other. The anion in 2 contains two different tridentate thiophosphate ligands, 1,3-P(2)S(8)(2-) and P(3)S(9)(3-), whereas the anion in 3 consists of two P(3)S(9)(3-) ligands coordinated to the central Ni atom. The anion in 4 is complex, consisting of four NiP(3)S(8)(-) clusters surrounding a central PS(4) tetrahedron; within the NiP(3)S(8)(-) groups, one P atom is directly bound to Ni. The discovery of these four new compounds demonstrates the versatility of ionothermal methods for the synthesis of novel thiophosphates.