Unraveling the structure of CO2- and H2O-bearing silicate melts

为了揭示含H2O和CO2的硅酸盐熔体的结构，我们用活塞式圆柱体装置和内热式气体压力容器合成了一系列组成的硅酸盐玻璃，并用各种核磁共振技术和拉曼光谱对其进行了表征。还进行了量子化学计算，以协助数据解释。这一研究为揭示硅酸盐熔体中H2O和CO2的溶解机理提供了新的见解。结果表明，在解聚硅酸盐熔体中，CO2主要以游离碳酸盐形式溶解，即不与硅酸盐网络相连的碳酸盐物种；在完全聚合的硅酸盐熔体中，CO2主要以网状碳酸盐和分子CO2形式溶解。

In order to unravel the structure of H2O- and CO2- bearing silicate melts, we have synthesized silicate glasses of a range of compositions using piston cylinder apparatus and internally heated gas pressure vessel, and have characterized them by various NMR techniques as well as Raman spectroscopy. Quantum chemical calculations were also performed to assist data interpretation. This study has provided new insights into the compositional dependency of H2O and CO2 dissolution mechanisms in silicate melts. It was confirmed that CO2 is dissolved in depolymerized silicate melts dominantly as free carbonates, i.e. carbonate species not linked to the silicate network, and dominantly as network carbonates and molecular CO2 in fully polymerized silicate melts.