Ba12 [BN2 ]6.67 H4 : A Disordered Anti-Skutterudite filled with Nitridoborate Anions.

Skutterudites are of high interest in current research due to their diversity of structures comprising empty, partially filled and filled variants, mostly based on metallic compounds. We herein present Ba12 [BN2 ]6.67 H4 , forming a non-metallic filled anti-skutterudite. It is accessed in a solid-state ampoule reaction from barium subnitride, boron nitride and barium hydride at 750 °C. Single-crystal X-ray and neutron powder diffraction data allowed to elucidate the structure in the cubic space group Im 3 ‾ ${\bar{3}}$ (no. 204). The barium and hydride atoms form a three-dimensional network consisting of corner-sharing HBa6 octahedra and Ba12 icosahedra. Slightly bent [BN2 ]3- units are located in the icosahedra and the voids in-between. 1 H and 11 B magic angle spinning (MAS) NMR experiments and vibrational spectroscopy further support the structure model. Quantum chemical calculations coincide well with experimental results and provide information about the electronic structure of Ba12 [BN2 ]6.67 H4 .

Combining Nitridoborates, Nitrides and Hydrides-Synthesis and Characterization of the Multianionic Sr6 N[BN2 ]2 H3.

Multianionic metal hydrides, which exhibit a wide variety of physical properties and complex structures, have recently attracted growing interest. Here we present Sr6 N[BN2 ]2 H3 , prepared in a solid-state ampoule reaction at 800 °C, as the first combination of nitridoborate, nitride and hydride anions within a single compound. The crystal structure was solved from single-crystal X-ray and neutron powder diffraction data in space group P21 /c (no. 14), revealing a three-dimensional network of undulated layers of nitridoborate units, strontium atoms and hydride together with nitride anions. Magic angle spinning (MAS) NMR and vibrational spectroscopy in combination with quantum chemical calculations further confirm the structure model. Electrochemical measurements suggest the existence of hydride ion conductivity, allowing the hydrides to migrate along the layers.

A Novel Nitridoborate Hydride Sr13 [BN2 ]6 H8 Elucidated from X-ray and Neutron Diffraction Data.

Metal hydrides are an uprising compound class bringing up various functional materials. Due to the low X-ray scattering power of hydrogen, neutron diffraction is often crucial to fully disclose the structural characteristics thereof. We herein present the second strontium nitridoborate hydride known so far, Sr13 [BN2 ]6 H8 , formed in a solid-state reaction of the binary nitrides and strontium hydride at 950 °C. The crystal structure was elucidated based on single-crystal X-ray and neutron powder diffraction in the hexagonal space group P63 /m (no. 176), exhibiting a novel three-dimensional network of [BN2 ]3- units and hydride anions connected by strontium cations. Further analyses with magic angle spinning (MAS) NMR and vibrational spectroscopy corroborate the presence of anionic hydrogen within the structure. Quantum chemical calculations reveal the electronic properties and support the experimental outcome. Sr13 [BN2 ]6 H8 expands the emerging family of nitridoborate hydrides, broadening the access to an open field of new, intriguing materials.

Lithium-ion Mobility in Li6 B18 (Li3 N) and Li Vacancy Tuning in the Solid Solution Li6 B18 (Li3 N)1-x (Li2 O)x.

All-solid-state batteries are promising candidates for safe energy-storage systems due to non-flammable solid electrolytes and the possibility to use metallic lithium as an anode. Thus, there is a challenge to design new solid electrolytes and to understand the principles of ion conduction on an atomic scale. We report on a new concept for compounds with high lithium ion mobility based on a rigid open-framework boron structure. The host-guest structure Li6 B18 (Li3 N) comprises large hexagonal pores filled with ∞ 1 [ ${{}_{{\rm { \infty }}}{}^{{\rm { 1}}}{\rm { [}}}$ Li7 N] strands that represent a perfect cutout from the structure of α-Li3 N. Variable-temperature 7 Li NMR spectroscopy reveals a very high Li mobility in the template phase with a remarkably low activation energy below 19 kJ mol-1 and thus much lower than pristine Li3 N. The formation of the solid solution of Li6 B18 (Li3 N) and Li6 B18 (Li2 O) over the complete compositional range allows the tuning of lithium defects in the template structure that is not possible for pristine Li3 N and Li2 O.

Strontium Nitridoborate Hydride Sr2BN2H Verified by Single-Crystal X-ray and Neutron Powder Diffraction.

Combining different anions in one material allows tuning of its structural, magnetic, and electronic properties. We hereby present the mixed anion compound Sr2BN2H, expanding the less-known class of nitridoborate hydrides. Solid-state reaction of Sr2N, BN, and SrH2 at 850 °C in a tube furnace yielded a gray, air- and moisture-sensitive powder of Sr2BN2H. It crystallizes as colorless platelets in the orthorhombic space group Pnma (no. 62) with a = 9.9164(2), b = 3.9079(1), and c = 10.1723(2) Å and Z = 4. An initial structural model was obtained from single-crystal X-ray diffraction data and corroborated by neutron powder diffraction data of the corresponding deuteride. Further validation by 1H and 11B MAS NMR, FTIR, and Raman spectroscopy complements the structural proof of anionic hydrogen present in the compound. Quantum chemical calculations support the experimental findings and reveal the electronic structure of Sr2BN2H.

Expanding the hydride chemistry: antiperovskites A3MO4H (A = Rb, Cs; M = Mo, W) introducing the transition oxometalate hydrides.

The four compounds A3MO4H (A = Rb, Cs; M = Mo, W) are introduced as the first members of the new material class of the transition oxometalate hydrides. The compounds are accessible via a thermal synthesis route with carefully controlled conditions. Their crystal structures were solved by neutron diffraction of the deuterated analogues. Rb3MoO4D, Cs3MoO4D and Cs3WO4D crystallize in the antiperovskite-like K3SO4F-structure type, while Rb3WO4D adopts a different orthorhombic structure. 2H MAS NMR, Raman spectroscopy and elemental analysis prove the abundance of hydride ions next to oxometalate ions and experimental findings are supported by quantum chemical calculations. The tetragonal phases are direct and wide band gap semiconductors arising from hydride states, whereas Rb3WO4H shows a unique, peculiar valence band structure dominated by hydride states.

Na3 SO4 H-The First Representative of the Material Class of Sulfate Hydrides.

The first representative of a novel class of mixed-anionic compounds, the sulfate hydride Na3 SO4 H, and the corresponding deuteride Na3 SO4 D were obtained from the solid-state reaction of NaH or NaD with dry Na2 SO4 . Precise reaction control is required, because too harsh conditions lead to the reduction of sulfate to sulfide. A combined X-ray and neutron diffraction study revealed that the compound crystallizes in the tetragonal space group P4/nmm with the lattice parameters a=7.0034(2) Šand c=4.8569(2) Å. The sole presence of hydride and absence of hydroxide ions is proven by vibrational spectroscopy and comparison with spectra predicted from quantum chemical calculations. 1 H and 23 Na MAS NMR spectra are consistent with the structure of Na3 SO4 H: a single 1 H peak at 2.9 ppm is observed, while two peaks at 15.0 and 6.2 ppm for the inequivalent 23 Na sites are observed. Elemental analysis and quantum chemical calculations further support these results.

Borate Hydrides as a New Material Class: Structure, Computational Studies, and Spectroscopic Investigations on Sr5 (BO3 )3 H and Sr5 (11 BO3 )3 D.

The unprecedented borate hydride Sr5 (BO3 )3 H and deuteride Sr5 (11 BO3 )3 D crystallizing in an apatite-related structure are reported. Despite the presence of hydride anions, the compound decomposes only slowly in air. Doped with Eu2+ , it shows broad-band orange-red emission under violet excitation owing to the 4f6 5d-4f7 transition of Eu2+ . The observed 1 H NMR chemical shift is in good agreement with previously reported 1 H chemical shifts of ionic metal hydrides as well as with quantum chemical calculations and very different from 1 H chemical shifts usually found for hydroxide ions in similar materials. FTIR and Raman spectroscopy of different samples containing 1 H, 2 H, nat B, and 11 B combined with calculations unambiguously prove the absence of hydroxide ions and the sole incorporation of hydride ions into the borate. The orange-red emission obtained by doping with Eu2+ shows that the new compound class might be a promising host material for optical applications.