The main uses of 1% mercury - 3% arsenic - 2% pyridine can be described as follows in the scope of "Tiangong Kaiwu":
Mercury, commonly known as mercury, was widely used in ancient times. First, in the field of alchemy, mercury is an important raw material for alchemy. The alchemists believed that through complex refining methods, mercury could interact with other drugs to refine the so-called elixir that could prolong life and even immortality. Many emperors and generals flocked to it, hoping to realize the dream of longevity. Second, in the gilding process, mercury is indispensable. Craftsmen first make gold and mercury into gold amalgam, and then apply it to the surface of the utensils. After heating, the mercury evaporates, and the gold firmly adheres to the utensils, so that the surface of the utensils appears bright golden and enhances its beauty and value. Third, in medicine, although mercury is highly toxic, some ancient physicians would cautiously use it for the treatment of certain special diseases, such as scabies and other skin diseases, using poison to fight poison, but the dosage and usage are very elegant.
Arsenic, in the form of realgar, orpiment and other forms, is common. In the field of ancient pigments, orpiment has significant uses. Because of its bright yellow and stable color, it is often used for painting and writing. When scholars and writers make mistakes in writing, they can use orpiment to apply and modify it, so there is the idiom "talk about it". Realgar plays an important role in traditional festival customs, such as the Dragon Boat Festival. People often add realgar to wine and drink it or apply it to the body, believing that it can ward off evil spirits and insects, and ensure safety and health. In addition, in traditional Chinese medicine, arsenic compounds are also used to treat some diseases, such as malaria, after being specially processed, but they are highly toxic and need to be used with extreme caution.
Pyridine, although it was not as clearly defined and recognized in ancient times as it is today, during the fermentation process of some natural products, substances containing pyridine ingredients may be produced. In the brewing industry, these ingredients may have subtle effects on the fermentation process and the flavor of the products. At the same time, in some traditional dyeing processes, after some plant or mineral raw materials are specially treated, the pyridine-containing substances may participate in the dyeing process, assisting the dye to better adhere to the fabric and improve the dyeing effect and color stability.

1. Mercury: Mercury is the only metal that is liquid at room temperature. It is silver-white in color, heavy in quality and good in fluidity. It has good electrical and thermal conductivity. However, it is highly toxic. If the human body accidentally inhales mercury vapor or accidentally eats mercury-containing substances, it will endanger health and cause damage to the nervous system, kidneys and other organs. In ancient times, mercury was often used to refine pills for longevity, but I did not know its harm, and many people who took pills caused illness or even death.
2. ** Bromine **: Bromine is a liquid non-metal, reddish-brown, with a strong pungent odor. Its volatility is very strong, and it can evaporate reddish-brown toxic fumes. Bromine has active chemical properties and is often used as an oxidizing agent. It is widely used in organic synthesis, pharmaceuticals and other fields. Although the understanding of bromine in ancient times was not as detailed as it is today, it may have been accidentally involved in some special chemical reactions and preparation of substances.
3. ** Cyanopyridine **: cyanopyridine, this compound is composed of a pyridine ring and a cyano group. Pyridine rings are aromatic, giving them certain stability and unique chemical activity. Cyanyl groups are active and can participate in a variety of chemical reactions, such as hydrolysis to form carboxyl groups and reactions with nucleophiles. Due to its special structure, it is of great significance in the field of pharmaceutical synthesis and can be used as a key intermediate for a variety of drugs, helping to develop new drugs to treat various diseases. In chemical production, it is often prepared with specific raw materials and reaction conditions.

To prepare 1-ether-3-ene-2-carbonyl indoles, there are many ways to synthesize them, which can be done in the following ways.
First, indole derivatives are used as starting materials and carbonyl groups are introduced through acylation reaction. First, indoles are reacted with acylating reagents, such as acyl halides or acid anhydrides, in a suitable catalyst, such as Lewis acid (anhydrous aluminum trichloride, etc.), in a suitable solvent (such as dichloromethane, etc.), to obtain indole intermediates containing carbonyl groups. Then, the intermediates are alkylated. In the presence of a base (potassium carbonate, etc.) and a palladium catalyst (tetra (triphenylphosphine) palladium, etc.), a coupling reaction occurs in an organic solvent (N, N-dimethylformamide, etc.), and alkenyl groups can be introduced. Finally, ether bonds are constructed by etherification reaction. Using halogenated hydrocarbons or sulfonate esters as etherification reagents, under basic conditions (strong bases such as sodium hydride) and reacting with the above products, the target product 1-ether-3-ene-2-carbonyl indole can be prepared.
Second, the alkenylation raw material can be started from. First, a suitable alkenyl compound is reacted with a halogenated indole in a palladium-catalyzed coupling system to achieve indole 3-enylation. Subsequently, a carbonylation reaction is carried out, using carbon monoxide and a suitable nucleophilic reagent (such as alcohol, etc.), under the catalysis of a transition metal catalyst (such as cobalt or rhodium complexes), a carbonyl group is introduced. Finally, through the etherification step, a suitable etherification reagent and a base are selected to achieve the construction of ether bonds, so as to obtain the target product.
Third, an ether bond and an alkenyl group can also be considered first. Select a suitable compound fragment containing alkenyl and ether bonds and react with indole derivatives. For example, by nucleophilic substitution or addition reaction, the fragment is first attached to the indole, and then the carbonylation reaction is carried out. With carbon monoxide and suitable nucleophilic reagents, under the action of specific catalysts and under appropriate reaction conditions, 1-ether-3-ene-2-carbonyl indoles are generated.
This is a feasible path for the synthesis of 1-ether-3-ene-2-carbonyl indoles. In actual operation, it is necessary to comprehensively weigh many factors such as the availability of raw materials, the difficulty of reaction conditions and the yield, and choose the optimal method.

Saltpeter, sulfur, and charcoal are the three most important substances used in gunpowder. Among them, saltpeter and sulfur must be handled with caution during storage and transportation.
Saltpeter is cold in nature and can purge fire and detoxify, but it has strong oxidizing properties. In case of flammable things, it is easy to cause disasters. When storing, it is necessary to choose a dry, cool and well-ventilated place to prevent it from being damp and deteriorating. And it must be kept away from fire sources, heat sources and flammable materials, and cannot be mixed with reducing substances such as charcoal, otherwise there will be a slight carelessness, or a violent reaction will cause the danger of explosion. During transportation, it should also be unloaded lightly, so as not to make bumps and collisions, causing damage to its packaging and the risk of leakage.
Sulfur, although relatively stable at room temperature, is flammable, and is very easy to burn in case of open flames and hot topics. Storage should avoid fires, keep the environment clean and tidy, and no debris should accumulate to avoid the spread of fire when it catches fire. During transportation, the packaging must be tight to prevent sulfur from being scattered. And the means of transportation also need to take fire prevention measures. Drivers and passengers should be familiar with its characteristics and emergency disposal methods to prevent accidents.
As for charcoal, although it is a common fuel, it is also flammable. When storing, it should be kept away from water sources to avoid moisture affecting the combustion performance, and it should be stored separately from saltpeter, sulfur, etc., to avoid danger caused by improper contact. During transportation, pay attention to covering, windproof and rainproof to prevent its quality from being damaged.
In the storage and transportation of these three, a slight mistake will cause disaster. The operator must be careful and strictly abide by the regulations to ensure safety.

1. ** Hazards of mercury **: Mercury is the most toxic thing. In the environment, it can be transported and transformed by the atmosphere, water, and soil. If water is contaminated with mercury, aquatic organisms will accumulate mercury. For example, fish in rivers, lakes and seas, if people eat them, mercury is easy to accumulate in the human body, damage the nervous system, cause numbness of limbs, tremor, and even life-threatening. And mercury can evaporate in the atmosphere and diffuse in the surroundings. After people inhale it, the viscera are damaged by it, especially the brain, which makes the mind dizzy.
2. ** Hazards of arsenic **: Arsenic is also highly toxic. If the soil contains high levels of arsenic, the growth of crops will be inhibited by it, and arsenic will be absorbed in the body. Humans eat such crops. Arsenic enters the human body. Chronic poisoning results in dark complexion and keratinized skin. Long-term exposure can cause serious diseases such as skin cancer and lung cancer. In the environment, arsenic contaminates water sources, and drinkers are prone to various diseases, such as cardiovascular diseases, diabetes, etc., which seriously affect the health of the population and harm future generations.
3. ** Hazards of lead **: Lead poisoning should not be underestimated. Lead can be stored in dust, wastewater, etc. Children are particularly sensitive. If exposed to lead-containing dust or ingested lead-contaminated food, lead is easy to accumulate in the body. Lead damage and children's nervous system development, resulting in mental retardation, learning disabilities, and behavioral abnormalities. In adults, lead can affect the hematopoietic system, cause anemia, and also affect the cardiovascular system, increasing blood pressure and heart disease risk. And lead contaminates soil, causes poor plant growth, and destroys ecological balance.
These three, mercury, arsenic, and lead, are all environmental disasters, and cause great damage to human health and ecological balance. We should make every effort to prevent and control, protect our environment, and ensure people's well-being.