Bykov Maxim, Bykova Elena, Chariton Stella, Prakapenka Vitali B, Batyrev Iskander G, Mahmood Mohammad F, Goncharov Alexander F
Department of Mathematics, Howard University, Washington, DC 20059, USA.
The Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC 20015, USA.
Dalton Trans. 2021 Jun 1;50(21):7229-7237. doi: 10.1039/d1dt00722j.
Synthesis and characterization of nitrogen-rich materials is important for the design of novel high energy density materials due to extremely energetic low-order nitrogen-nitrogen bonds. The balance between the energy output and stability may be achieved if polynitrogen units are stabilized by resonance as in cyclo-N5- pentazolate salts. Here we demonstrate the synthesis of three oxygen-free pentazolate salts Na2N5, NaN5 and NaN5·N2 from sodium azide NaN3 and molecular nitrogen N2 at ∼50 GPa. NaN5·N2 is a metal-pentazolate framework (MPF) obtained via a self-templated synthesis method with nitrogen molecules being incorporated into the nanochannels of the MPF. Such self-assembled MPFs may be common in a variety of ionic pentazolate compounds. The formation of Na2N5 demonstrates that the cyclo-N5 group can accommodate more than one electron and indicates the great accessible compositional diversity of pentazolate salts.
由于存在极具能量的低阶氮-氮键，富氮材料的合成与表征对于新型高能量密度材料的设计至关重要。如果多氮单元如环戊唑盐那样通过共振得以稳定，那么能量输出与稳定性之间的平衡或许能够实现。在此，我们展示了在约50吉帕的压力下，由叠氮化钠NaN₃和分子氮N₂合成三种无氧的戊唑盐Na₂N₅、NaN₅和NaN₅·N₂。NaN₅·N₂是一种金属-戊唑骨架（MPF），通过自模板合成法获得，其中氮分子被纳入MPF的纳米通道。这种自组装的MPF在各种离子型戊唑化合物中可能很常见。Na₂N₅的形成表明环戊唑基团能够容纳不止一个电子，这也预示着戊唑盐具有丰富多样的可及组成。
