4-bromothiophene-2-carbaldehyde

Lead and mercury, the genus of hardware. Lead is heavy and heavy in quality, blue and black in color, and its shape is soft and malleable. At room temperature, it is relatively stable, but when heated, it is easy to melt. When melted, the smoke rises and has a pungent smell. Mercury, commonly known as mercury, is a liquid metal, silver-white in color, with a metallic luster, flowing like beads, rolling on the utensils, difficult to capture. It is active, volatile, and toxic to steam.
Both lead and mercury have their unique physical properties. Lead has good electrical and thermal conductivity, so it is useful in the production of many utensils. And its corrosion resistance is good, and it can be used to protect the outer layer, such as the ancient pipe wrap, to prevent erosion. Mercury has a great density and often plays a role in gravity-related experiments and equipment. Because of its liquid state of flow, it is also a key thing in pressure measuring instruments.
Although lead and mercury are useful, their toxicity should not be underestimated. Lead enters the human body, and it is difficult to excrete for a long time. It can cause poor qi and blood, damage people's internal organs, especially the liver and kidneys, which makes people tired and weak, and their complexion is yellow. If the mercury vapor is inhaled by people, it can disturb people's nervous system, causing headaches, insomnia, tremors and other diseases. The ancients often involved lead and mercury in alchemy and other techniques, and they did not know the harm, and many of them caused diseases because of it. Therefore, when using lead and mercury, you should know its nature, handle it with caution, and do not forget its harm because of its benefits.

Lead and mercury are the genus of hardware. Lead is heavy in nature and heavy in quality, black as black jade. Its shape is soft and malleable, and at room temperature, it seems to have a lazy state. When it is calcined by fire, it turns into a flowing liquid, like smart water, which can be cast into a dish.
Mercury, commonly known as mercury, is the only liquid metal. Its color is silvery white, its luster is dazzling, and it is very smart and elusive. Touch it and disperse, gather it and form beads, like a spirit. Lively and volatile, when heated it rises into gas, ethereal and invisible.
The chemical properties of lead have a certain stability and can react with acids and bases. It interacts with dilute sulfuric acid and hydrochloric acid to slowly generate hydrogen gas and gradually erode the surface. In case of strong oxidizing acids, such as nitric acid, the reaction is violent and the corresponding lead salt is formed. Lead can also combine with oxygen and remain in the air for a long time, and a lead oxide film is formed on the surface, which can slow down its further oxidation.
The chemical activity of mercury is also not weak. It can form amalgam with a variety of metals. This property has been used in ancient times, such as in the extraction of gold and silver in metallurgy. Mercury is mixed and ground with sulfur powder to synthesize mercury sulfide, which is often used to deal with mercury pollution. And under heating conditions, mercury can combine with oxidation to form mercury oxide. This process is reversible and has been an important reaction for Lavoisier's study of air composition.
Both are toxic. Lead enters the human body and accumulates in the organs and bones, damaging the nervous system and hematopoietic system, causing mental retardation and anemia. Mercury vapor inhalation, or mercury compounds enter the body through the mouth and skin, injuring the liver and kidneys, causing neurological disorders, tremors in the limbs, and mental abnormalities. Therefore, when using it, be careful to prevent its harm from being invisible.

Mercury is a highly toxic thing, and everyone should be careful. Today, it is related, especially the preparation of mercury.
The preparation of mercury has been done in ancient times. First, burn it with Dan sand. For Dan sand, mercury sulfide is also. "Baopuzi" says: "Dan sand burns into mercury, and the accumulation changes into Dan sand." This is the manifestation of the wisdom of the ancients. Put Dan sand in an airtight container, calcined with fire, Dan sand is decomposed by heat, sulfur and mercury are separated, mercury is turned into a gas, and condensed into liquid mercury. Second, the cinnabar sand is co-heated with iron filings. The cinnabar sand is also mercury sulfide, and iron is more active than mercury. The two are co-heated. Iron and sulfide combine, and mercury is released free, which can also obtain mercury.
However, the preparation of mercury must be done with caution. Mercury is volatile, and its vapor is highly toxic. It is inhaled into the human body, damaging the organs and nerves, and causing great harm. Therefore, when preparing, it must be in a well-ventilated place, well-protected, and safe.
The use of mercury was often involved in alchemy and medicine in ancient times. Alchemists wanted to use mercury to refine the medicine of longevity, but mercury poisoning caused many deaths. It is a false move. In medicine, although mercury has the effect of sterilization, it is also highly toxic, and it has been used with caution today. In this world, mercury is still used in chemical, instrumentation and other fields. However, due to its toxicity, the dosage is decreasing day by day, and they are also trying to find alternatives.
The production of mercury is related to safety and the environment. When using it, consider the pros and cons, and use scientific methods to protect people's health and ensure the safety of nature.

"Tiangong Kaiwu" says: Mercury, that is, mercury, flows in its nature, and soars in case of fire. The art of lead and mercury has been used in ancient times, and the use of lead and mercury is also quite extensive.
Mercury is often the key thing in the realm of alchemy. Ancient alchemists, who desire the elixir of immortality, mostly use mercury as raw material. Due to the unique characteristics of mercury, it can be combined with various gold and stone medicinal materials, and in the cauldron of alchemy, it can undergo wonderful changes after being calcined by the heat. At that time, alchemists believed that through specific formulas and refining methods, mercury could be converted into miraculous elixirs, which could prolong life and even become immortals.
In the field of metallurgy, mercury also has its functions. Mercury can form amalgams with certain metals, which makes it useful for extracting precious metals such as gold and silver. For example, in the extraction of placer gold, gold-containing sand is mixed with mercury, which can absorb gold, and then heat and other processes to volatilize the mercury, so as to obtain relatively pure gold. This method played a very important role in the extraction of precious metals in ancient mining.
Furthermore, in the field of medicine, mercury and its compounds have also been used. In ancient medical books, there are occasional records of people who use mercury-containing drugs to treat diseases. However, mercury is toxic, and improper use can easily lead to poisoning, so extreme caution is required when using it. It may be used to treat skin diseases such as scabies. It is coated with mercury agent to take advantage of its sterilization and disinfection properties in order to cure the disease. However, with the deepening of the understanding of mercury toxicity, its application in medicine has become more cautious.
As for lead, it is widely used in the foundry industry. Lead is soft, has a low melting point, and is easy to cast and form. In ancient bronze casting, an appropriate amount of lead was often added to improve the properties of the alloy, making the casting more durable, and has good fluidity, which is conducive to the casting of complex shapes. Lead is also used to make type, which plays an important role in the printing field and contributes to the dissemination and inheritance of culture.

In today's world, business conditions are ever-changing, and there are also traces to follow if you want to push the market price of nail crabs. Nail crabs are delicious in meat and rich in nutrients. They are treasures in food, and the market demand is quite strong.
The price depends on the season. When crabs are fat in autumn, the production of nail crabs is abundant, the market supply is sufficient, and the price may be flat. As the old saying goes: "When the autumn wind rises, the crab's feet are itchy, and the navel is round in September and the navel is sharp in October." At this time, crabs are expensive, and ordinary people can also eat them. The price per catty may be around tens to hundreds of dollars.
Furthermore, the origin and quality are related to the price. If it comes from a place with famous products, such as Yangcheng Lake, the water quality is clear, and the nail crab paste produced is full of yellow fertilizer, the reputation is far-reaching, and the price is not cheap. Such a good product, or a few gold catties, cannot be compared elsewhere. There are also wild nail crabs, whose growth environment is natural, strong vitality, and tight meat is also preferred by diners. Compared with breeders, the price is often several percent higher.
In addition, changes in market supply and demand are also key. On festive days, people compete to buy nail crabs for relatives and friends, and the demand increases greatly. If the supply does not make great progress, the price will rise. On the contrary, if the market is sluggish and the demand is sluggish, the price will drop.
Overall, the market price of nail crabs varies according to the season, origin, quality, and supply and demand. The usual price of cultured products may be around a hundred dollars per catty, and the price of famous products or wild products may be several gold. The market changes, and it is difficult to determine the above factors.