每统一体积基于保持电子的精力，我们扩大坚硬的概念到原子僵硬，离子的僵硬和契约坚硬，在这三点调查材料坚硬的性质铺平。而材料坚硬是......

Pressure has an important effect on chemical bonds and their chemical properties.The atypical compounds NaCl3 and CsF3 a......