章节大纲

  • A ruby crystal, valued for its beauty and utility in technology, shown in raw form.

    Why are crystals appealing?

    ::为什么水晶有吸引力?

    Crystals are found everywhere chemical deposits are located.  The ruby crystal shown above is extremely valuable, both because of its beauty and its utility in equipment such as lasers.  For some people, crystals are said to have magical qualities.  For others, the “magic” is in the regular structure of the crystal as the and line up in a regular order.
    ::上面显示的红宝石晶体极有价值,因为它的美丽和在激光等设备中的实用性。对一些人来说,晶体据说具有魔力。对另一些人来说,“魔力”在晶体的常规结构中,作为定序的晶体和定序线。

    Ionic Crystal Structure
    ::电离水晶结构

    dot diagrams show the nature of the electron transfer that takes place between metal and atoms.  However, do not exist as discrete molecules, as the dot diagrams may suggest.  In order to minimize the potential energy of the system , ionic compounds take on the form of an extended three-dimensional array of alternating cations and anions.  This maximizes the attractive forces between the oppositely charges .  The figure below shows two different ways of representing the ionic crystal lattice.  A ball and stick model makes it easier to see how individual ions are oriented with respect to one another.  A space filling diagram is a more accurate representation of how the ions pack together in the crystal .
    ::圆点图显示金属和原子之间电子传输的性质。 但是, 并不像圆点图可能显示的那样作为离散分子存在。 为了最大限度地减少系统的潜在能量, 离子化合物以一个交替的电离层的三维延伸阵列的形式出现。 这使反向电荷之间的吸引力最大化。 下图显示两种不同的方式代表离子晶体。 一个球和棍子模型更容易看到单个离子如何相互定向。 一个空间填充图更准确地显示了离子是如何在晶体中组合在一起的。

    Two models of sodium chloride crystal structure: expanded view and space-filling model.

    Two models of a sodium chloride crystal are shown. The purple spheres represent the Na + ions, while the green spheres represent the Cl − ions. (A) In an expanded view, the distances between ions are exaggerated, more easily showing the coordination numbers of each ion. (B) In a space filling model, the electron clouds of the ions are in contact with each other.
    :伤心A) 在扩大的视野中,离子之间的距离被夸大,更容易显示每离子的协调号。 (B) 在空间填充模型中,离子的电子云相互接触。

    Naturally occurring sodium chloride (halite) does not look at first glance like the neat diagrams shown above. It is only when we use modern techniques to analyze the crystal structure at the atomic level that we can see the true regularity of the organized ions.
    ::自然产生的氯化钠(卤化钠)与上面显示的整洁图表相比,初见不鲜。 只有当我们使用现代技术分析原子层的晶体结构时,我们才能看到有组织离子的真正规律性。

    A pink halite crystal specimen with cubic formations exhibiting a natural structure.

    Halite crystals.
    ::卤化物晶体

     

     

    Summary
    ::摘要

    • Ionic compounds take on the form of extended three-dimensional arrays of cations and anions.
      ::电离化合物的形式是三维长的电离体和电离体阵列。
    • The arrangement maximizes the attractive force between oppositely-charged ions.
      ::这种安排最大限度地扩大了反充电离子之间的吸引力。

    Review
    ::回顾

    1. Why do ionic compounds form crystal structure instead of discrete molecules?
      ::为什么离散分子是离散化合物形成的晶体结构?
    2. Ions arrange themselves in three-dimensional array to maximize what type of force
      ::离子排列成三维阵列,以最大限度地扩大何种类型的力
    3. Which of the following would best describe how ions in an ionic compound arrange themselves?
      1. randomly
        ::随机随机
      2. an orderly pattern
        ::有序模式

      ::以下哪一种最能说明离子在电离化合物中是如何排列的?