概括
从体中心立方体 (bcc) 过渡到面中心立方体 (fcc) 在6.9 GPa. 这种结构变化会影响其密度和体积模量,并对高压物理产生影响.
科学领域:
- 材料科学 材料科学 材料科学
- 凝聚物质物理学 凝聚物质物理学
- 高压物理 高压物理
背景情况:
- 在极端条件下了解元素金属的相变对于材料科学至关重要.
- 在高压下的结构性行为为金属物理提供了洞察力.
研究的目的:
- 为了研究在高压下的结构相变.
- 为了确定的体中心立方 (bcc) 和面中心立方 (fcc) 阶段的特性.
主要方法:
- 在上进行了高压实验.
- 在特定的压力和温度点分析结构变化.
主要成果:
- 在6.9千兆帕斯卡尔 (GPa) 和296凯尔文时从bcc转变为fcc结构.
- fcc结构比bcc结构密度高0.25%,6.9 GPa,bcc的相对体积为0.718.
- 两个阶段的散装模量及其压力导数都被计算出来,显示出更硬的fcc结构.
结论:
- 该研究确定了中bcc-fcc相过渡的临界压力.
- 外推表明的三重点大约在15 GPa和500 K.
- 这些发现有助于理解元素金属的高压相位图.
相关概念视频
Ionic Crystal Structures
Ionic crystals consist of two or more different kinds of ions that usually have different sizes. The packing of these ions into a crystal structure is more complex than the packing of metal atoms that are the same size.
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
Resonance and Hybrid Structures
According to the theory of resonance, if two or more Lewis structures with the same arrangement of atoms can be written for a molecule, ion, or radical, the actual distribution of electrons is an average of that shown by the various Lewis structures.
Resonance Structures and Resonance Hybrids
The Lewis structure of a nitrite anion (NO2−) may actually be drawn in two different ways, distinguished by the locations of the N–O and N=O bonds.
Resonance Structures and Resonance Hybrids
The Lewis structure of a nitrite anion (NO2−) may actually be drawn in two different ways, distinguished by the locations of the N–O and N=O bonds.
Weak Acid Solutions
Few compounds act as strong acids. A far greater number of compounds behave as weak acids and only partially react with water, leaving a large majority of dissolved molecules in their original form and generating a relatively small amount of hydronium ions. Weak acids are commonly encountered in nature, being the substances partly responsible for the tangy taste of citrus fruits, the stinging sensation of insect bites, and the unpleasant smells associated with body odor. A familiar example of a...
Ionic Bonding and Electron Transfer
Ions are atoms or molecules bearing an electrical charge. A cation (a positive ion) forms when a neutral atom loses one or more electrons from its valence shell, and an anion (a negative ion) forms when a neutral atom gains one or more electrons in its valence shell. Compounds composed of ions are called ionic compounds (or salts), and their constituent ions are held together by ionic bonds: electrostatic forces of attraction between oppositely charged cations and anions.


