BrF 5 can be prepared by treating BrF 3 with fluorine under UV light in the region of 300 to 400 nm at room temperature. It was analyzed by UV-Vis, NMR, IR and Raman spectroscopy. Its crystal structure was redetermined by X-ray diffraction, and its space group was corrected to Pnma. Quantum-chemical calculations were performed for the band assignment of the vibrational spectra. A monoclinic polymorph of BrF 5 was quantum chemically predicted and then observed as its low-temperature modification in space group P2 1 /c by single crystal X-ray diffraction. BrF 5 reacts with the alkali metal fluorides AF (A = K, Rb) to form alkali metal hexafluoridobromates(V), A[BrF 6 ] the crystal structures of which have been determined. Both compounds crystallize in the K[AsF 6 ] structure type (R � 3, no. 148, hR24). For the species [BrF 6 ] + , BrF 5 , [BrF 6 ] À , and [IF 6 ] À , the chemical bonds and lone pairs on the heavy atoms were investigated by means of intrinsic bond orbital analysis.

The reaction of Cs [BrF 6 ] with BrF 5 gave the compound Cs[Br 3 F 16 ] with the unprecedented propeller-shaped, C 3 -symmetric [(μ 3 -F)(BrF 5 ) 3 ] À anion. All other currently known fluoridobromates(V) contain only octahedral [BrF 6 ] À anions, which, unlike the related [IF 6 ] À anions, never exhibited stereochemical activity of the lone pair on the Br atoms. Despite the same coordination number of six for the Br atom in the [BrF 6 ] À and [(μ 3 -F)(BrF 5 ) 3 ] À anions, the longer μ 3 -FÀ Br bonds provide additional space, allowing the lone pairs on the Br atoms to become stereochemically active. Cs[Br 3 F 16 ] was characterized by single-crystal X-ray diffraction, Raman spectroscopy, and quantum-chemical calculations for both the solid-state compound and the isolated anion at 0 K. Intrinsic bond orbital calculations show that the μ 3 -FÀ Br bond is essentially ionic in nature and also underpin the stereochemical activity of the lone pairs of the Br(V) atoms.

The purely chemical synthesis of fluorine is a spectacular reaction which for more than a century had been believed to be impossible. In 1986, it was finally experimentally achieved, but since then this important reaction has not been further studied and its detailed mechanism had been a mystery. The known thermal stability of MnF4 casts serious doubts on the originally proposed hypothesis that MnF4 is thermodynamically unstable and decomposes spontaneously to a lower manganese fluoride and F2. This apparent discrepancy has now been resolved experimentally and by electronic structure calculations. It is shown that the reductive elimination of F2 requires a large excess of SbF5 and occurs in the last reaction step when in the intermediate [SbF6][MnF2][Sb2F11] the addition of one more SbF5 molecule to the [SbF6]− anion generates a second tridentate [Sb2F11]− anion. The two tridentate [Sb2F11]− anions then provide six fluorine bridges to the Mn(II) cation thereby facilitating the reductive elimination of the two fluorine ligands as F2.

Two types of layered sulfido stannates or a molecular cluster compound are obtained upon ionothermal treatment of the simple sulfido stannate salt K4[SnS4] ·  4H2O that is based on binary tetrahedral [SnS4]4− anions. The formation of the respective products, novel compounds (C4C1C1Im)2[Sn3S7] (1 a), (C4C1C2Im)2[Sn3S7] (1 b), and (C4C1C2Im)2[Sn4S9] (2) with layered anionic substructures, or the recently reported compound (C4C1C1Im)4+x[Sn10O4S16(SMe)4][An]x (A) comprising a molecular cluster anion, is controlled by both the choice of the ionic liquid cation and the reaction temperature. We report the scale‐up of the syntheses by a factor of 100 with regard to other reported ionothermal syntheses of related compounds, and a procedure of how to isolate them in phase‐pure form – both being rare observations in chalcogenido stannate chemistry in ionic liquids. Moreover, the synthesis of compound 1 a can be achieved by rapid cation exchange starting out from 1 b, which has not been reported for organic cations in any chalcogenido stannate salt to date.

In this work, we have re-investigated the structural and physical properties of UI 3 by means of temperature dependent powder neutron diffraction, heat capacity and magnetic measurements. We confirm that UI 3 crystallizes in the PuBr 3 structure type, space group Cmcm. We did not observe any temperature dependent structural phase transition in the temperature range from 10 to 300 K. We further report the first quantum chemical calculations of UI 3 by density functional theory (DFT). The calculated structural and electronic properties demonstrate the pronounced two-dimensional anisotropic effects present in UI 3 due to its layered structure.