1 Fluoro 2 Iodo 5 Nitrobenzene

1. The use of ***: In ancient times, there were a variety of use cases. In "Xunzi · Confucian Effect", it is said that "to live in Chu and Chu, to live in the more and more, to live in summer and summer, it is not natural, and it is caused by accumulation. This is called dyeing and migration, such as entering the pool and changing with each other". Here, the pool is often a place where water gathers. In terms of agricultural irrigation, it can store water sources for nourishment in the surrounding fields. And in the layout of ancient settlements, the pool sometimes has a drainage function, which can prevent the disaster of waterlogging in the settlement.
2. ** The use of the wat **: The wat was what the ancient ministers held when they were in the upper hall. " The Book of Rites · Jade Zao contains "If there is a finger painted in front of the monarch, use a wat; if the order is made in front of the monarch, use a wat". Its primary function is to record, the minister faces the monarch and is afraid of forgetting something, so he will write down the main points on the wat; at the same time, the wat is also a ceremonial symbol. The material and shape of the wat held by officials of different levels are slightly different to show their status. For example, the regulation of the wat of officials of different grades is detailed in "Sui Shu · Etiquette Chronicle".
3. ** Uses of ribose **: Ribose is of great significance in life activities. Ribose is an important component of ribonucleic acid (RNA), which participates in the transmission and expression of genetic information in Taking protein synthesis as an example, messenger RNA (mRNA) carries the genetic code, transfer RNA (tRNA) transports amino acids with structures such as ribose, and ribosomal RNA (rRNA) constitutes ribosomes to participate in protein assembly. Ribose, as a key component of the RNA skeleton, ensures the orderly transmission of genetic information and protein synthesis. At the same time, in cellular energy metabolism, some coenzymes such as ATP (adenosine triphosphate) contain ribose in their adenosine part. ATP, as the "currency" of energy circulation in the cell, participates in many energy-requiring reactions. Ribose is essential for maintaining its structural stability and function.

Mercury is the most negative in nature, and its body is extremely flexible. Its quality is like water, which is silver-like and white. At room temperature, it is in a flowing state and has a metallic luster. "Tiangong Kaiwu" said: "Mercury can digest gold and silver into mud, like plating." This is one of the major characteristics of mercury, and it can form amalgam with metals such as gold and silver. This reaction is quite wonderful.
Lead is heavy in nature, blue and gray in color, soft in texture, and easy to stretch. Its density is high, and the ancients often used it as a tool, such as lead hammer, lead plate, etc. And lead has good corrosion resistance and is not easy to rust in humid environments. This property makes it used in many fields such as construction and chemical industry.
Diatomaceous earth, which is deposited from the remains of ancient diatoms, is white or yellowish in color, light and porous. Its pore structure is well developed and has excellent adsorption properties. It can absorb impurities, odors and harmful gases in water, so it is often a good material for water purification and air purification. And because of its stable chemical properties, good heat insulation and sound insulation properties, it can be used for the preparation of heat insulation materials and sound insulation materials.
Mercury is volatile, and its vapor is toxic, which is extremely harmful to the human body. Excessive inhalation can cause mercury poisoning and damage the nervous system, kidneys and other organs. Although lead is stable, excessive intake can also endanger human health, affecting the nervous system, hematopoietic system, etc. And because of its special structure and properties, diatomaceous earth is relatively safe and widely used, and has important value in many industries. These three have unique physical properties, which are either helpful or hidden dangers in production and life in ancient and modern times. It is necessary to make good use of them and prevent their harm.

Lead, mercury, and cadmium are common heavy metals. Although arsenic is not a metal in the strict sense, it is often classified as a heavy metal, and it has many unique chemical properties.
Lead is soft in texture, a blue-white heavy metal, with good ductility and corrosion resistance. At room temperature, a basic lead carbonate film will form on the surface of lead in the air, which can prevent further oxidation. Lead can react with dilute hydrochloric acid and dilute sulfuric acid, but because the generated lead chloride and lead sulfate are insoluble, it will cover the surface of lead and stop the reaction. Lead can also react with nitric acid to form lead nitrate. There are many kinds of lead compounds, such as lead oxide, and there are different forms such as Huangdan (PbO) and Mystic Monitor Tuo (PbO), which are often used in pigments, glass manufacturing and other fields.
Mercury, commonly known as mercury, is the only metal that exists in a liquid state at room temperature and pressure. Mercury has good fluidity, high surface tension, and a silver-white color. Mercury is relatively stable in chemical properties. It does not react with dilute hydrochloric acid or dilute sulfuric acid, but can react with oxidizing acids such as concentrated sulfuric acid and concentrated nitric acid. Mercury can dissolve a variety of metals to form amalgams, and this property has applications in metallurgy, dentistry, etc. Mercury compounds such as mercury chloride (mercuric, HgCl ²) are extremely toxic, and mercury sulfide (cinnabar, HgS) is a common mineral pigment, and its chemical properties are relatively stable.
Cadmium is a silver-white shiny metal, soft, tough and malleable. Cadmium is quite stable in air, and an oxide film forms on the surface to prevent further oxidation. Cadmium can react with dilute acids to replace hydrogen. Among cadmium compounds, cadmium sulfate, cadmium nitrate, etc. are soluble, while cadmium sulfide is a yellow precipitate and is often used as a pigment.
Arsenic is non-metallic, but its properties are similar to metals. When arsenic is heated in air, it will burn to form arsenic trioxide (arsenic, As O 🥰), which is highly toxic. Arsenic can react with oxidizing acids such as nitric acid to form corresponding arsenic acids. Arsenic compounds are diverse in form, arsenite and arsenate exist in nature, and some organic arsenic compounds are used in medicine and agriculture, but most arsenic compounds are toxic.
These numbers have different chemical properties, but they are often toxic. They accumulate in the environment and living organisms, causing many hazards. Therefore, their use and discharge must be strictly controlled.

As recorded in "Tiangong Kaiwu", the method is mostly to put calamine (zinc carbonate) and charcoal in a sealed mud tank, and heat it to refine it. The method is as follows:
Choose calamine first, and it is better to have pure and non-heterogeneous whiskers. Crush it like powder and mix it with charcoal powder in a certain proportion. Charcoal needs to be made of good materials to ensure firepower and reduction effect.
Prepare a mud tank. The material of the mud tank needs to be resistant to high temperature and has good sealing. Put the mixed calamine powder and charcoal powder into the mud tank and seal the mouth of the tank to prevent air from entering.
Heat in the furnace, the heat is extremely critical. At first, it is dried slowly over a low fire to make the mud can and the materials in it gradually warm and drive away moisture. Then increase the firepower and use strong heat to decompose and reduce calamine. The melting point of zinc is low, and it is heated into a liquid. After cooling, zinc blocks can be obtained.
The book also says that during operation, beware of oxidation of zinc liquid in contact with air. If the seal of the mud can is not good and air penetrates, zinc is easy to oxidize, which affects the purity and yield of zinc smelting.
The process of zinc smelting also requires craftsmen to master the heat and time. If the heat is insufficient, zinc cannot be fully restored; if the heat is too high, zinc or volatilization and dissipation are not suitable.
So, using calamine as raw material, according to the above ancient method, through the steps of material selection, mixing, sealing, heating, etc., zinc can be obtained.

When storing and transporting heavy metals such as mercury, lead, and cadmium, pay careful attention to many key matters.
Mercury is a liquid metal that is highly volatile and can evaporate into mercury vapor at room temperature, which is highly toxic. When storing mercury, the first heavy seal should be used in thick-walled glass containers, and water seals should be used to prevent mercury from evaporating and escaping. The storage place should be cool and well ventilated, away from heat and fire sources, because high temperature will promote mercury evaporation. When transporting mercury, the packaging must be solid and tight, mostly in metal cans or special plastic containers, with an appropriate amount of absorbent built in to absorb mercury vapor that may evaporate. Transportation vehicles must also ensure good ventilation and avoid violent vibration and collision to prevent mercury leakage due to damage to the container.
The storage of lead should be in a dry and non-corrosive environment. Because lead is easily oxidized in humid air to form a lead oxide film, although it can prevent further oxidation to a certain extent, it will still be corroded in a humid or corrosive environment such as acid and alkali for a long time. When storing lead products, avoid mixing with other metals to prevent electrochemical reactions from accelerating corrosion. When transporting lead, protective measures should be taken to ensure that the lead products are stable and will not be damaged by collisions during transportation. If transporting lead compounds, because of their toxicity, it is necessary to strictly follow the regulations on the transportation of hazardous chemicals and do a good job of marking and protection.
Cadmium is also very toxic. When storing cadmium, ensure that the storage environment is dry and cool, and away from oxidants and acids, because contact with acids can produce flammable and toxic hydrogen. Cadmium is usually stored in bulk, granular or powdery form, and must be well sealed to prevent environmental pollution and human inhalation hazards caused by dust flying. When transporting cadmium, the packaging must meet relevant safety standards to prevent cadmium leakage. Avoid mixing with other chemicals during transportation to prevent dangerous reactions. In the event of cadmium leakage, emergency measures should be taken quickly, such as covering with inert materials such as sand, and proper disposal after collection to prevent cadmium from spreading and polluting soil and water sources.