The perovskite phase (CH3 NH3 )2 Pb(SCN)2 I2 with a structure closely related to the K2 NiF4 -type was identified as the product of the reaction of CH3 NH3 I and Pb(SCN)2 by single-crystal X-ray analysis. This extends the range of suitable dyes for solar cell applications to a class of perovskite-related structures of the general composition (AMX3 )n (AX)m .

New alkali borosulfates were obtained by precipitation from oleum, solid-state reactions, or thermal decomposition. The crystal structures were characterized with single-crystal data. They are all based on corner-linked BO4 and SO4 tetrahedra with varying coordination of the alkali cations. According to the ratio of BO4 and SO4 tetrahedra, different frameworks are observed, i.e., noncondensed complex anions (1:4), one-dimensional chains (1:3), or three-dimensional (3D) networks (1:2). This is in analogy to silicates, where the ratio Si/O relates to the dimensionality also. For Na5[B(SO4)4], which exists in two different polymorphs, there are noncondensed pentameric units. Na5[B(SO4)4]-I: space group Pca21, a = 10.730(2) Å, b = 13.891(3) Å, c = 18.197(4) Å. Na5[B(SO4)4]-II: space group P212121, a = 8.624(2) Å, b = 9.275(2) Å, c = 16.671(3) Å. A3[B(SO4)3] (A = K, Rb) are isotypic with Ba3[B(PO4)3] adopting space group Ibca [K3[B(SO4)3], a = 7.074(4) Å, b = 14.266(9) Å, c = 22.578(14) Å; Rb3[B(SO4)3], a = 7.2759(5) Å, b = 14.7936(11) Å, c = 22.637(2) Å] with vierer chains of BO4tetrahedra based on two bridging and two terminal SO4 tetrahedra. Li[B(SO4)2] [space group Pc, a = 7.6353(15) Å, b = 9.342(2) Å, c = 8.432(2) Å, and β = 92.55(2)°] comprises a 3D network that is closely related to β-tridymite. Li[B(S2O7)2] [space group P212121, a = 10.862(2) Å, b = 10.877(2) Å, c = 17.769(4) Å] represents the first example of a disulfate complex with noncondensed [B(S2O7)2](-) units. Vibrational spectra were recorded from all compounds, and the thermal behavior was also investigated.

The structural principles of borosulfates derived from the B/S ratio are confirmed and extended to new representatives of this class showing novel motifs. According to the composition, Na[B(S2O7)2] (P2(1)/c; a=10.949(6), b=8.491(14), c=12.701(8) Å; β=110.227(1)°; Z=4) and K[B(S2O7)2] (Cc; a=11.3368(6), b=14.662(14), c=13.6650(8) Å; β=94.235(1)°; Z=8) contain isolated [B(S2O7)2](-) ions, in which the central BO4 tetrahedron is coordinated by two disulfate units. The alkali cations have coordination numbers of 7 (Na) and 8 (K), respectively. The structure of Cs[B(S2O7)(SO4)] (P2(1)/c; a=10.4525(6), b=11.3191(14), c=8.2760(8) Å; β=103.206(1); Z=4) combines, for the first time, sulfate and disulfate units into a chain structure. Cs has a coordination number of 12. The same structural units were found in H[B(S2O7)(SO4)] (P2(1)/c; a=15.6974(6), b=11.4362(14), c=8.5557(8) Å; β=90.334(3)°; Z=8). This compound represents the first example of a polyacid. The hydrogen atoms were located and connect the chains to form layers through hydrogen-bonding bridges. H3O[B(SO4)2] (P4/ncc; a=9.1377(6), c=7.3423(8) Å; Z=4) is the first oxonium compound of this type to be found. The BO4 tetrahedra are linked by SO4 tetrahedra to form linear chains similar to those in SiS2. The chains form a tetragonal rod packing structure with H3O(+) between the rods. The structures of borosulfates can be classified following the concept described by Liebau for silicates, which was extended to borophosphates by Kniep et al. In contrast to these structures, borosulfates do not comprise B-O-B bonds but instead contain S-O-S connections. All compounds were obtained as colourless, moisture-sensitive single crystals by reaction of B2O3 and the appropriate alkali salt in oleum.

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The reaction of alkali sulfates and boron oxide in oleum yielded the complexes A[B(S 2 O 7 ) 2 ] (A = Li, Na, K, NH 4 ). This way we obtained the first ammonium-containing borosulfate and we determined the crystal structure. NH 4 [B(S 2 O 7 ) 2 ] [Cc, Z = 8, a = 11.4403(2), b = 14.9439(2) c = 13.8693(2) Å] crystallizes isotyp to K[B(S 2 O 7 ) 2 ]. Thermal decomposition or treatment in vacuo resulted in compounds with composition A[B(SO 4 ) 2 ]. One-dimensional chain structures are obtained for A = Na, K, NH 4 . NH 4 [B(SO 4 ) 2 ] [P4/ncc, Z = 4, a = 9.1980(1), c = 7.4258(1) Å] and K[B(SO 4 ) 2 ] [P4/ncc, Z = 4, a = 8.9739(3), c = 7.4114(3) Å] are isotyp with H 3 O[B(SO 4 ) 2 ]. The chains

Mild fluorination of high‐energy nickel‐cobalt‐manganese (HE‐NCM) materials with low pressures of elementary fluorine gas (F2) at room temperature was systematically studied. The fluorinated HE‐NCM samples were analysed by ion chromatography, inductively coupled plasma mass spectrometry, FT‐IR spectroscopy, powder X‐ray diffraction, magic angle spinning NMR spectroscopy, scanning electron microscopy, thermo‐gravimetric analysis, differential thermal analysis, electrochemical testing, and X‐ray photoelectron spectroscopy. The treatment of the cathode materials with low pressures (a few hundred mbar) of elementary fluorine gas at room temperature led to the elimination of the basic surface film (LiOH, Li2CO3, Li2O, etc.), and the resulting thin amorphous LiF film led to increased capacity and long‐term stability of the battery. Impedance built‐up was greatly reduced for these systems throughout cycling. Fluorination with F2 only causes the formation of O−Me−F bonds (Me=Transition Metal), when treated with F2 at higher pressures. If O−Me−F bonds are formed, it may be detrimental to the electrode surface film resistance and cycle stability of the electrodes. However, it may be that the LiF surface content, which can expand as long as the LiMeO2 structure can be oxidized and Li+ can be extracted, has become too large and thus detrimental. Considering the evolution of differential capacity plots and taking into account the thermodynamic driving force of the F2 treatment, it is likely that the same activation processes that occur electrochemically in Li‐rich materials also occur chemically, when the material is exposed to F2. Differential capacity plots show enhanced Mn4+ reduction peaks upon lithiation, when the material was exposed to F2, only possible after activation of the Li2MnO3 phase. For this reason, we believe fluorination promotes to some extent an activation of this phase.

Borosulfates are oxoanionic compounds consisting of condensed sulfur‐ and boron‐centered tetrahedra. Hitherto, they were mostly achieved from solvothermal syntheses in SO 3 ‐enriched sulfuric acid, or from reactions with the superacid H[B(HSO 4 ) 4 ]. The crystal structures are very similar to those of the corresponding class of silicates and their substitution variants, especially regarding the typical structural motif of corner‐sharing tetrahedra. However, the borosulfates are supposed to be even more versatile, because (BO 3 ) units might also be part of the anionic network. The following article deals with detailed reports on the different synthesis strategies, the crystal chemistry of borosulfates in comparison to silicates, and their hitherto identified properties.

Detailed investigations by XRD reveal that the precursor “HPbI3” that was obtained by reaction of aq. conc. hydroiodic acid HI and PbI2 in DMF is (CH3)2NH2PbI3. (CH3)2NH2+ is formed by solvent reaction as already described in the literature but not properly assigned. Attempts to synthesize HPbI3 by gas phase reaction of PbI2 with aq. conc. HI yielded light‐yellow crystals of the oxonium salt H18O8Pb3I8 (Pbam, Z = 2, a = 10.075, b = 30.162, c = 4.5664 Å). The crystal structure of H18O8Pb3I8 consists of trimeric ribbons of edge‐sharing PbI6 octahedra. These ribbons [Pb3I8]2– are separated by protonated fragments of crystalline ice [H18O8]2+ or (H2O)6(H3O+)2. H18O8Pb3I8 can also be precipitated from PbI2 and aq. conc. HI. H18O8Pb3I8 is not stable at room temperature but transforms within a few days to light‐yellow (H3O)2x(H2O)2–2xPb1–xI2 with x ≈ 0.23 (R3m, Z = 3, a = 4.5554, c = 29.524 Å). The crystal structure represents a CdCl2‐type layer structure with H2O/H3O+ in between. Charge compensation is achieved by Pb2+ vacancies. Via topotactic reaction (H3O)2x(H2O)2–2xPb1–xI2 releases H2O/HI and forms crystals of the pristine PbI2. All steps were characterized by P‐XRD, IR/Raman spectra, and UV/Vis spectra. H18O8Pb3I8 acts as a precursor for the synthesis of MAPbI3 because the reaction with gaseous CH3NH2 yields MAPbI3, so it can mimic a composition “HPbI3”.