Laniel Dominique, Winkler Bjoern, Koemets Egor, Fedotenko Timofey, Chariton Stella, Milman Victor, Glazyrin Konstantin, Prakapenka Vitali, Dubrovinsky Leonid, Dubrovinskaia Natalia
Material Physics and Technology at Extreme Conditions, Laboratory of Crystallography, University of Bayreuth, Bayreuth, 95440, Germany.
Institut für Geowissenschaften, Abteilung Kristallographie, Johann Wolfgang Goethe-Universität Frankfurt, Altenhöferallee 1, Frankfurt am Main, D-60438, Germany.
IUCrJ. 2021 Feb 5;8(Pt 2):208-214. doi: 10.1107/S2052252521000075. eCollection 2021 Mar 1.
At high pressures, autoionization - along with polymerization and metallization - is one of the responses of simple molecular systems to a rise in electron density. Nitro-sonium nitrate (NONO ), known for this property, has attracted a large interest in recent decades and was reported to be synthesized at high pressure and high temperature from a variety of nitro-gen-oxygen precursors, such as NO, NO and N-O mixtures. However, its structure has not been determined unambiguously. Here, we present the first structure solution and refinement for nitro-sonium nitrate on the basis of single-crystal X-ray diffraction at 7.0 and 37.0 GPa. The structure model (2/ space group) contains the triple-bonded NO cation and the NO -trigonal planar anion. Remarkably, crystal-chemical considerations and accompanying density-functional-theory calculations show that the oxygen atom of the NO unit is positively charged - a rare occurrence when in the presence of a less-electronegative element.
在高压下，自电离——与聚合和金属化一起——是简单分子系统对电子密度升高的反应之一。硝酸硝鎓（NONO ）因其这一特性而闻名，在近几十年引起了广泛关注，据报道它是在高温高压下由多种氮-氧前驱体，如NO、NO和N-O混合物合成的。然而，其结构尚未得到明确确定。在此，我们基于7.0和37.0 GPa下的单晶X射线衍射，首次给出了硝酸硝鎓的结构解析和精修。结构模型（空间群2/ ）包含三键连接的NO阳离子和NO -三角平面阴离子。值得注意的是，晶体化学考量以及伴随的密度泛函理论计算表明，NO单元的氧原子带正电荷——在存在电负性较小的元素时这种情况很少见。
