Single crystals of orthorhombic black phosphorus can be grown by a short way transport reaction from red phosphorus and Sn/SnI 4 as mineralization additive. Sizes of several millimeters can be realized with high crystal quality and purity, making a large area preparation of single or multilayer phosphorene possible. An in situ neutron diffraction study has been performed addressing the formation of black phosphorus. Black phosphorus is formed directly via gas phase without the occurrence of any other intermediate phase. Crystal growth was initiated after cooling the starting materials down from elevated temperatures at 500 °C. Highlights:-Large black phosphorus crystals were grown by a short way transport reaction -In situ neutron diffraction affirm the formation of black P directly from gas phase -Large crystals can be used as starting material for phosphorene synthesis

Fibrous phosphorus is one of the known crystalline allotropes under standard pressure conditions. It has been predicted prior to its successful synthesis and structural characterization. The allotrope consists of parallel, tubular double strands of phosphorus, in contrast to the violet form of Hittorf's phosphorus, where the same strands are arranged in a perpendicular orientation towards each other. This structural similarity results in an almost identical energetic stability * Prof. Dr. T. Nilges

Keywords: Lithium / Phosphorus / Polyphosphides / Density functional calculations / Raman spectroscopy / IR spectroscopy

Solids with high ion mobility are of broad interest for energy storage applications. New systems featuring low-activated ion mobility are important to improve the performance in such systems. Herein we report on a model system dealing with such improved properties. Li 0.2 CdP 2 was synthesized from the elements, lithium as structure stabilizer and CdI 2 as reaction promoters in sealed silica ampoules at 823 K. It crystallizes tetragonal, in space group I4 1 22 (a-CdAs 2 structure type), with lattice parameters a ¼ 7.6691(8)Å, c ¼ 4.4467(4)Å and V ¼ 261.53(4)Å 3 . After 24 h of storage in air lithium ions can be removed in a spontaneous delithiation reaction resulting in Li(OH)$H 2 O formation on the surface of the crystals. Formed a 0 -CdP 2 adopts the a-CdAs 2 structure type. Both compounds consist of isolated cadmium atoms and helical 1 N [P À ]-chains generating empty channels suitable to accommodate Li ions. The heavy atom structure was determined by X-ray diffraction methods while a full model including lithium was derived from a combined solid state NMR and quantum chemical calculation approach. An low activation barrier range in the order of 0.1 to 0.2 eV was determined by NMR spectroscopy pointing towards an extraordinary high Li mobility in Li 0.2 CdP 2 . Of course a Cd-based solid will have certain disadvantages like toxicity and mass for storage applications but substitution of Cd by suitable lighter elements can solve this issue.

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