Kristallstruktur von Hexamincyclotriphosphazen, P3N3(NH2)6

Generation of a π-Bonded Isomer of [P4 ]4- by Aluminyl Reduction of White Phosphorus and its Ammonolysis to PH3

By employing the highly reducing aluminyl complex [K{(NON)Al}]₂ (NON=4,5-bis(2,6-diisopropylanilido)-2,7-di-tert-butyl-9,9-dimethylxanthene), we demonstrate the controlled formation of P₄ ^2- and P₄ ^4- complexes from white phosphorus, and chemically reversible inter-conversion between them. The tetra-anion features a unique planar π-bonded structure, with the incorporation of the K⁺ cations implicit in the use of the anionic nucleophile offering additional stabilization of the unsaturated isomer of the P₄ ^4- fragment. This complex is extremely reactive, acting as a source of P^3- : exposure to ammonia leads to the release of phosphine (PH₃ ) under mild conditions (room temperature and pressure), which contrast with those necessitated for the direct combination of P₄ and NH₃ (>5 kbar and >250 °C).

Sr3 P3 N7 : Complementary Approach by Ammonothermal and High-Pressure Syntheses

Nitridophosphates exhibit an intriguing structural diversity with different structural motifs, for example, chains, layers or frameworks. In this contribution the novel nitridophosphate Sr3 P3 N7 with unprecedented dreier double chains is presented. Crystalline powders were synthesized using the ammonothermal method, while single crystals were obtained by a high-pressure multianvil technique. The crystal structure of Sr3 P3 N7 was solved and refined from single-crystal X-ray diffraction and confirmed by powder X-ray methods. Sr3 P3 N7 crystallizes in monoclinic space group P2/c. Energy-dispersive X-ray and Fourier-transformed infrared spectroscopy were conducted to confirm the chemical composition, as well as the absence of NHx functionality. The optical band gap was estimated to be 4.4 eV using diffuse reflectance UV/Vis spectroscopy. Upon doping with Eu2+ , Sr3 P3 N7 shows a broad deep-red to infrared emission (λem =681 nm, fwhm≈3402 cm-1 ) with an internal quantum efficiency of 42 %.

Crystalline Nitridophosphates by Ammonothermal Synthesis

Nitridophosphates are a well-studied class of compounds with high structural diversity. However, their synthesis is quite challenging, particularly due to the limited thermal stability of starting materials like P₃ N₅ . Typically, it requires even high-pressure techniques (e.g. multianvil) in most cases. Herein, we establish the ammonothermal method as a versatile synthetic tool to access nitridophosphates with different degrees of condensation. α-Li₁₀ P₄ N₁₀ , β-Li₁₀ P₄ N₁₀ , Li₁₈ P₆ N₁₆ , Ca₂ PN₃ , SrP₈ N₁₄ , and LiPN₂ were synthesized in supercritical NH₃ at temperatures and pressures up to 1070 K and 200 MPa employing ammonobasic conditions. The products were analyzed by powder X-ray diffraction, energy dispersive X-ray spectroscopy, and FTIR spectroscopy. Moreover, we established red phosphorus as a starting material for nitridophosphate synthesis instead of commonly used and not readily available precursors, such as P₃ N₅ . This opens a promising preparative access to the emerging compound class of nitridophosphates.

SrP3N5O: a highly condensed layer phosphate structure solved from a nanocrystal by automated electron diffraction tomography

The oxonitridophosphate SrP(3)N(5)O has been synthesized by heating a multicomponent reactant mixture that consisted of phosphoryl triamide OP(NH(2))(3), thiophosphoryl triamide SP(NH(2))(3), SrS, and NH(4)Cl enclosed in evacuated and sealed silica-glass ampoules up to 750 °C. The compound was obtained as nanocrystalline powder with needle-shaped crystallites. The crystal structure was solved ab initio on the basis of electron diffraction data by means of automated electron diffraction tomography (ADT) and verified by Rietveld refinement with X-ray powder diffraction data. SrP(3)N(5)O crystallizes in the orthorhombic space group Pnma (no. 62) with unit-cell data of a=18.331(2), b=8.086(1), c=13.851(1) Å and Z=16. The compound is a highly condensed layer phosphate with a degree of condensation κ=½. The corrugated layers (∞)(2){(P(3)N(5)O)(2-)} consist of linked, triangular columns built up from P(O,N)(4) tetrahedra with 3-rings and triply binding nitrogen atoms. The Sr(2+) ions are located between the layers and exhibit six-, eight-, and ninefold coordination. FTIR and solid-state NMR spectra of SrP(3)N(5)O are discussed as well.

Unprecedented zeolite-like framework topology constructed from cages with 3-rings in a barium oxonitridophosphate

A novel oxonitridophosphate, Ba(19)P(36)O(6+x)N(66-x)Cl(8+x) (x ≈ 4.54), has been synthesized by heating a multicomponent reactant mixture consisting of phosphoryl triamide OP(NH(2))(3), thiophosphoryl triamide SP(NH(2))(3), BaS, and NH(4)Cl enclosed in an evacuated and sealed silica glass ampule up to 750 °C. Despite the presence of side phases, the crystal structure was elucidated ab initio from high-resolution synchrotron powder diffraction data (λ = 39.998 pm) applying the charge flipping algorithm supported by independent symmetry information derived from electron diffraction (ED) and scanning transmission electron microscopy (STEM). The compound crystallizes in the cubic space group Fm ̅3c (no. 226) with a = 2685.41(3) pm and Z = 8. As confirmed by Rietveld refinement, the structure comprises all-side vertex sharing P(O,N)(4) tetrahedra forming slightly distorted 3(8)4(6)8(12) cages representing a novel composite building unit (CBU). Interlinked through their 4-rings and additional 3-rings, the cages build up a 3D network with a framework density FD = 14.87 T/1000 Å(3) and a 3D 8-ring channel system. Ba(2+) and Cl(-) as extra-framework ions are located within the cages and channels of the framework. The structural model is corroborated by (31)P double-quantum (DQ) /single-quantum (SQ) and triple-quantum (TQ) /single-quantum (SQ) 2D correlation MAS NMR spectroscopy. According to (31)P{(1)H} C-REDOR NMR measurements, the H content is less than one H atom per unit cell.