Nitridophosphate – eine Erfolgsgeschichte der Nitridsynthese

Abstract

Nitridophosphate und Phosphornitride sind außerordentlich gut untersuchte Nitrid‐Verbindungen, deren Synthesemethoden sich, angefangen bei der Kondensation molekularer Vorläuferverbindungen bei moderaten Temperaturen und Umgebungsdruck, zu den heutzutage gängigen Hochtemperatur‐ und Hochdrucksynthesen weiterentwickelt haben. Seit Beginn der systematischen Forschung an Nitridophosphaten vor 30 Jahren hat diese Methodenentwicklung zu einer großen Element‐ und Strukturvielfalt geführt. In diesem Kurzaufsatz berichten wir über die Fortschritte der Nitridophosphat‐Synthese, insbesondere im Hinblick auf das allseits präsente Problem bei Nitriden: die Oxidationsanfälligkeit von Nitridionen.

Tetra‐Face‐Capped Octahedra in a Tetrahedra Network – Structure Determination and Scanning Transmission Electron Microscopy of SrAl5P4N10O2F3

“…Nitridophosphates feature a large diversity of crystal structures due to the isolobal relation between P−N and Si−O bonds, which preserves a close analogy to silicate‐related structural motifs like discrete tetrahedra, layers and networks [1] . Compared to silicate bonds, the elemental combination of phosphorus and nitrogen offers a more covalent bonding situation due to a smaller electronegativity difference, and thus, a more significant structural rigidity.…”

Synthesis of Nitride Zeolites in a Hot Isostatic Press

“…The versatile compound class of nitridophosphates has been researched in detail for more than 30 years. [1] The structural diversity of nitridophosphates can be derived from their close relationship to oxosilicates, as the element combination Si/O is isoelectronic with P/N, and similar with oxosilicates which are built up from SiO4 tetrahedra, the PN4 tetrahedron is the fundamental building unit in nitridophosphates. However, nitridophosphates can even feature edge-sharing tetrahedra due to the higher covalence (and lower polarity) of P-N bonds compared to Si-O in oxosilicates.…”

“…However, nitridophosphates can even feature edge-sharing tetrahedra due to the higher covalence (and lower polarity) of P-N bonds compared to Si-O in oxosilicates. [1,2] Additionally, the higher valence of nitrogen allows for higher degrees of condensation (i.e. atomic ratio κ of tetrahedra centers to tetrahedra vertices).…”

“…atomic ratio κ of tetrahedra centers to tetrahedra vertices). [1,3] But despite numerous investigations, nitridophosphate synthesis has ever been challenging, as the most common starting material phosphorus(V) nitride (P3N5) is prone to thermal decomposition above 850 °C. [4] Therefore, high-pressure hightemperature methods (e.g.…”

“…multianvil technique) have been employed for their synthesis, since elevated nitrogen pressure suppresses the thermally induced elimination of N2 from P3N5. [1] This high-pressure strategy led to a large number of nitridophosphates with various incorporated electropositive elements. However, sample quantities have intrinsically been limited by high-pressure techniques.…”