含氮矿物以及NH4Cl水溶液氮同位素平衡分馏数据

氮广泛分布在地表和地球内部，氮循环对地球的演化和地球宜居性形成有重要作用，但我们对N循环的认识还非常有限。氮在不同体系中的同位素分馏特性是认识N循环的基础，我们用第一性原理计算的方法系统研究了流体和矿物间N的平衡同位素分馏系，在流体和硅酸盐矿物中N主要以NH4+离子的形式存在，还有一些N以硝酸盐形式存在。我们研究发现N的最近邻有4个H原子，证实了N在流体中种型是NH4+离子，但流体中N－H键要远比硅酸盐矿物中N－H键长，也比硝酸铵和硫酸铵中的N－H键长，流体中的N形成了最弱的键，在平衡N同位素分馏条件下，流体相对于硅酸盐矿物和硝酸盐更轻，例如在300K，硬玉和流体间的N同位素分馏是12.5‰。N循环过程中，流体更倾向于带走的轻N同位素。硅酸盐矿物比硝酸盐更重。研究工作2020年发表在Geochimica et Cosmochimica Acta杂志上。本数据集包括相关的计算数据及图表。

Nitrogen is widely distributed across the Earth's surface and interior. The nitrogen cycle plays a critical role in Earth's evolution and the development of its habitability, yet our understanding of the N cycle remains extremely limited. The isotopic fractionation characteristics of nitrogen in various systems are the fundamental basis for deciphering the N cycle. We systematically investigated the equilibrium isotopic fractionation factors of N between fluids and minerals using first-principles calculations. In both fluids and silicate minerals, nitrogen primarily exists as NH4+ ions, with a small portion also present as nitrate. Our study found that each nitrogen atom has four neighboring hydrogen atoms, confirming that the dominant nitrogen species in fluids is NH4+ ions. However, the N-H bonds in fluids are considerably longer than those in silicate minerals, and even longer than those in ammonium nitrate and ammonium sulfate, indicating that the N in fluids forms the weakest bonds. Under equilibrium N isotopic fractionation conditions, fluids are isotopically lighter than both silicate minerals and nitrates. For instance, at 300 K, the N isotopic fractionation between jadeite and fluids is 12.5‰. During the N cycle, fluids preferentially carry away the lighter nitrogen isotopes, while silicate minerals are isotopically heavier than nitrates. This research was published in *Geochimica et Cosmochimica Acta* in 2020. This dataset contains relevant computational data and figures.