金刚石和石墨——结构、用途、性质、应用
“碳”这个词来自拉丁语“carbo”，意思是“木炭”。它是宇宙中第四丰富的元素，也是人体中第二丰富的元素，这可能会让我们感到惊讶（第一个是氧气）。实际上，地球上的所有有机物质都含有某种形式或元素的碳，这就是为什么它是整个有机化学学科的基础。
碳中的电子数为6，等于它的原子序数。碳是一种以字母表示的非金属。它由质子、中子和电子组成，它们的计数均为 6。因为它几乎可以与其他碳原子无限连接，所以碳原子被认为是独特而非凡的。这是因为它的原子很小，这使得它可以很容易地融入更大的分子中。它的每个原子在其外壳中都有四个价电子，可以与分子和其他原子形成化学连接。
什么是碳的同素异形体？
The allotropes of carbon are diamond and graphite, respectively. Chemically, these minerals are made up of carbon atoms with various physical properties. These minerals are classified as polymorphs because they have the same chemical but different crystalline structures.
金刚石和石墨中由碳原子组成的原子通过强共价键结合在一起，在碳的两种同素异形体中具有不同的构型。
宝石和石墨都是纯碳，并包含代表其各种特性的移位结构。另一方面，石墨颗粒与三个碳原子形成键并与平行板连接。钻石颗粒进入宝石框架中的四个碳原子。
钻石
Diamond is a type of carbon that has its atoms arranged in a diamond cubic crystal structure. Another solid form of carbon known as graphite is the chemically stable form of carbon at ambient temperature and pressure, but diamond almost never transforms to it.
金刚石具有所有天然物质中最高的硬度和导热性，使其成为行业切割和抛光设备的理想选择。这也是为什么金刚石砧座细胞可能会将材料暴露在地下深处的压力下。
金刚石的结构
据报道，钻石的碳原子与其他四个碳原子形成强烈的化学相互作用，形成了一个完美无瑕的四面体结构，延伸到整个晶体中。碳原子是sp3杂化的，碳-碳原子键长相等。因此，在 Diamond 中出现了强共价连接的三维网络。
金刚石的熔点约为 3843 K，密度约为 3.51 g/cm3。众所周知，它是一种不良的电导体，因为它的价电子被困在 CC sigma 共价键中，阻止它们导电。
金刚石的应用
- 钻石是地球上最坚硬的物质，具有多种用途和应用。它用于制造用于磨削、切割、钻孔和其他任务的工具。
- 金刚石用于生产灯泡中使用的钨丝。
- 它是一种用于制作珠宝的金属。
- 大多数外科医生使用钻石作为去除眼睛白内障的高精度仪器。
石墨
Graphite is a crystalline carbon that occurs naturally. It’s a mineral that can be found in metamorphic and igneous rocks as a native element. Graphite is a mineral with a wide range of properties.
它具有低比重并且非常柔软。它以非常轻的压力进行切割。另一方面，当与几乎任何其他物质接触时，它具有极强的耐热性和几乎惰性。由于其极端的特性，它在冶金和工业中有着广泛的应用。
石墨的结构
结构：据说石墨中的所有碳原子都与其他三个碳原子具有稳定的化学相互作用，从而形成类似于铁丝网的薄片；微弱的力量将板材快速固定到位。当您用铅笔在纸上书写时，这些纸张会滑开，从而在页面上留下石墨碎片作为污点。
在石墨结构中，碳原子是 sp2 杂化并在同一平面上取向，形成六边形环。环中有几层颗粒。石墨的密度为 2.26 g/cm3，据说具有低电导率。
石墨的应用
- 石墨粉以分散材料或粉末的形式用作润滑剂。
- 在铅笔中，通常使用石墨。
- 它被用于生产电解电池的碳电极，因为它是一种良好的电导体。
- 由于其熔点高，用于生产石墨坩埚。
- 它存在于许多核反应堆和减速器中。
示例问题
问题一：石墨的来源是什么？
回答：
As a result of the sedimentary reduction of carbon compounds during metamorphism, graphite forms in metamorphic rocks. Meteorites and igneous rocks both contain graphite. Calcite, quartz, tourmaline, and micas are minerals that are linked with graphite. China, Canada, Mexico, Madagascar, and Brazil are the main export destinations for mined graphite, in order of tonnage.
Graphite coexists with silicate and troilite minerals in meteorites. Cliftonite is a small graphitic crystal found in meteoritic iron. Some minuscule grains have unique isotopic compositions, indicating that they existed before the Solar system was established. They are one of approximately 12 well-known mineral forms that predate the Solar System and have been found in molecular clouds. When supernovae detonated or low- to intermediate-sized stars evacuated their outer envelopes late in their lives, these minerals were produced in the ejecta. Graphite may be the Universe’s second or third oldest mineral.
问题 2：钻石的材料特性是什么？
回答：
Diamond is a solid form of pure carbon with atoms organised in a crystal structure. Solid carbon comes in a variety of allotropes depending on the chemical bond type. Diamond is one of the most prevalent pure carbon allotropes. The bonds in Diamond are sp3 orbital hybrids, and the atoms are arranged in tetrahedra, each with four nearest neighbours.
Tetrahedra are solid, and the bonds are strong, and Diamond has the most atoms per unit volume of any known substance, which is why it is both the least and the hardest to compress.It also has a higher density, ranging from 3520 kg/m3 in pure Diamond to 3150 to 3530 kg/m3 in natural diamonds (about three times the density of water).
问题3：为什么石墨导电而金刚石不导电？
回答：
Each carbon atom in a single crystal of diamond is surrounded by four other carbon atoms by covalent connections, forming the four corners of a regular tetrahedron. There are no free electrons since each carbon atom is bound by four covalent bonds. Diamond is a poor conductor of electricity due to the lack of free electrons within its crystalline structure
Every carbon atom in a single crystal of graphite is covalently connected to three other carbon atoms. One valence electron is left free for each carbon atom since each carbon atom possesses four valence electrons. By adding electric potential to these liberated electrons, they can easily flow within the crystalline structure of graphite. As a result, graphite is an excellent conductor of electricity.
问题 4：当您说“变性酒精”时，它意味着什么？变性酒精的具体用途是什么？
回答：
Denatured alcohol is alcohol that has been turned unfit by mixing it with harmful compounds such as methanol, pyridine, copper sulphate, and so on. Ethanol is a widely used chemical in industry. As a result, it was subjected to an extremely low excise duty. It is necessary to denature alcohol in order to prevent its overuse for drinking purposes.
问题5：醛和酮分子之间存在哪些结构差异？
回答：
The carbonyl group of an aldehyde is linked to one alkyl group (R) and one hydrogen atom, whereas the carbonyl group of a ketone is attached to two alkyl groups.
问题 6：对洗涤剂的成分进行了哪些更改以使其可生物降解？
回答：
Detergents derived from long-chain hydrocarbons with the least amount of branching in their molecules breakdown faster.