Syntheses, structures and Raman spectra of Cd(BF4)(AF6) (A=Ta, Bi) compounds

Molecular-Level Zn-Ion Transfer Pump Specifically Functioning on (002) Facets Enables Durable Zn Anodes

The modification of metallic Zn anode contributes to solving the cycling issue of Zn-ion batteries (ZIBs) by restraining the dendrite growth and side reactions. In this regard, modulating (002) Zn is an effective way to prolong the lifespan of ZIBs with a parallel arrangement of Zn deposition. Herein, the authors propose to add trace amounts of Zn(BF₄ )₂ additive in 3 M ZnSO₄ to promote in-plane Zn deposition by forming a BF₄ ^- -[Zn(H₂ O)₆ ]²⁺ -[Zn(BF₄ )₃ ]^- transfer process and specifically functioning on (002) facets. In this way, the optimized electrolyte highly boosts the cycling stability of Zn anodes with a long lifespan at 34.2% Zn utilization (500 h/10 mA cm^-2 ) and 51.3% Zn utilization (360 h/10 mA cm^-2 ; 834 h/1 mA cm^-2 ). Moreover, the electroplated Zn on Cu substrate exhibits a competitive cumulative plating capacity (CPC) of 2.87 Ah cm^-2 under harsh conditions. The assembled Zn|(NH₄ )₂ V₆ O₁₆ ·3H₂ O full cells with a high cathode loading of 29.12 mg cm^-2 also realizes almost no capacity degradation even after 2000 cycles at 2 A g^-1 . With this cost-effective strategy, it is promising to push the development of aqueous ZIBs as well as provide inspiration for metal anode optimization in other energy storage systems.

K3Na(TaF7)(SiF6): a mixed-anion pentanary fluoride with zero-dimensional anions exhibiting a large band gap

Metal halides have potential applications in many optics-related fields, such as birefringence materials. Here, a pentanary fluoride K₃Na(TaF₇)(SiF₆) has been obtained through a facile hydrothermal route. It crystallizes in the orthorhombic space group Immm, and its zero-dimensional framework features isolated SiF₆ octahedra and TaF₇ monocapped trigonal prisms, a new type of combination representing a new structure-type. It exhibits two wide optical band gaps of 4.46 eV and 5.67 eV which is consistent with DFT calculation. K₃Na(TaF₇)(SiF₆) exhibits a larger birefringence (0.045 at 253.7 nm) compared with the commercial MgF₂ crystal.

Nitro-sonium tetra-fluorido-borate, NOBF4

The crystal structure of oxido-nitro-gen(1+) tetra-fluorido-borate (nitro-sonium tetra-fluorido-borate), NO+BF4 -, was refined on the basis of single-crystal X-ray diffraction data at 150 K. The compound crystallizes in the baryte structure type with ortho-rhom-bic Pnma symmetry. The crystal structure exhibits cationic disorder with equal occupation of N and O atoms at the same site.

Iron Fluoroanions and Their Clusters by Electrospray Ionization of a Fluorinating Ionic Liquid

Metal fluoroanions are of significant interest for fundamental structure and reactivity studies and for making isotope ratio measurements that are free from isobaric overlap. Iron fluoroanions [FeF(4)](-) and [FeF(3)](-) were generated by electrospray ionization of solutions of Fe(III) and Fe(II) with the fluorinating ionic liquid 1-ethyl-3-methylimidazolium fluorohydrogenate [EMIm](+)[F(HF)(2.3)](-). Solutions containing Fe(III) salts produce predominately uncomplexed [FeF(4)](-) in the negative ion spectrum, as do solutions containing salts of Fe(II). This behavior contrasts with that of solutions of FeCl(3) and FeCl(2) (without [EMIm](+)[F(HF)(2.3)](-)) that preserve the solution-phase oxidation state by producing the gas-phase halide complexes [FeCl(4)](-) and [FeCl(3)](-), respectively. Thus, the electrospray-[EMIm](+)[F(HF)(2.3)](-) process is oxidative with respect to Fe(II). The positive ion spectra of Fe with [EMIm](+)[F(HF)(2.3)](-) displays cluster ions having the general formula [EMIm](+) (n+1)[FeF(4)](-) n, and DFT calculations predict stable complexes, both of which substantiate the conclusion that [FeF(4)](-) is present in solution stabilized by the imidazolium cation. The negative ion ESI mass spectrum of the Fe-ionic liquid solution has a very low background in the region of the [FeF(4)](-) complex, and isotope ratios measured for both [FeF(4)](-) and adventitious [SiF(5)](-) produced values in close agreement with theoretical values; this suggests that very wide isotope ratio measurements should be attainable with good accuracy and precision when the ion formation scheme is implemented on a dedicated isotope ratio mass spectrometer.