CNRS & Chimie ParisTech, UMR 7575 LECIME, 11 rue Pierre et Marie Curie, 75005 Paris, France.
Phys Chem Chem Phys. 2013 Oct 14;15(38):16012-8. doi: 10.1039/c3cp51817e. Epub 2013 Aug 20.
While the energetic stability of the large number of possible SiO2 polymorphs has been widely addressed by both experimental and theoretical studies, there is a real dearth of information on their mechanical properties. We performed a systematic study of the elastic properties of 121 pure silica zeolites, including both experimentally synthesized and hypothetical structures, by means of density-functional theory calculations. We found that most frameworks exhibit high elastic anisotropy, and the experimentally synthesized structures are among the most mechanically stable ones. We propose to extend the "feasibility" criterion proposed in earlier literature to include elastic anisotropy, allowing to further reduce the number of possible targets for synthesis of SiO2 polymorphs. We also predict that a small number of hypothetical pure silica zeolites present large negative linear compressibility (NLC), which we link to the wine-rack motif of their framework.
虽然大量可能的二氧化硅多晶型体的能量稳定性已经被实验和理论研究广泛研究过，但关于它们的力学性能的信息却非常缺乏。我们通过密度泛函理论计算对 121 种纯硅沸石的弹性性质进行了系统的研究，包括实验合成的和假设的结构。我们发现大多数骨架表现出很高的弹性各向异性，而实验合成的结构是其中最稳定的。我们建议将早期文献中提出的“可行性”标准扩展到包括弹性各向异性，从而进一步减少合成二氧化硅多晶型体的可能目标的数量。我们还预测，少数假设的纯硅沸石具有较大的负线性压缩率（NLC），我们将其与框架的酒架图案联系起来。
