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Stabilization of Polynitrogen Anions in Tantalum–Nitrogen Compounds at High Pressure
Author(s) -
Bykov Maxim,
Bykova Elena,
Ponomareva Alena V.,
Abrikosov Igor A.,
Chariton Stella,
Prakapenka Vitali B.,
Mahmood Mohammad F.,
Dubrovinsky Leonid,
Goncharov Alexander F.
Publication year - 2021
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202100283
Subject(s) - tantalum , nitrogen , chemistry , limiting , high pressure , diamond anvil cell , ambient pressure , inorganic chemistry , organic chemistry , thermodynamics , mechanical engineering , physics , engineering
The synthesis of polynitrogen compounds is of great importance due to their potential as high‐energy‐density materials (HEDM), but because of the intrinsic instability of these compounds, their synthesis and stabilization is a fundamental challenge. Polymeric nitrogen units which may be stabilized in compounds with metals at high pressure are now restricted to non‐branched chains with an average N−N bond order of 1.25, limiting their HEDM performances. Herein, we demonstrate the synthesis of a novel polynitrogen compound TaN 5 via a direct reaction between tantalum and nitrogen in a diamond anvil cell at circa 100 GPa. TaN 5 is the first example of a material containing branched all‐single‐bonded nitrogen chains [N 5 5− ] ∞ . Apart from that we discover two novel Ta–N compounds: TaN 4 with finite N 4 4− chains and the incommensurately modulated compound TaN 2−x , which is recoverable at ambient conditions.