4-Pyridinecarboxylic acid, 2-chloro-5-fluoro-

Heavy metals such as mercury, lead, and arsenic and their compounds were mostly used in alchemy, medicine, and some special processes in ancient times.
In the field of alchemy, the ancients believed that immortality could be achieved by refining pills, and mercury, lead, etc. were often used as raw materials for alchemy. Scholars believed that mercury had magical changing properties. Heating could generate red mercury oxide, which cooled down and turned back into mercury. This change was regarded as a magical symbol of "longevity", so it appeared frequently in alchemy formulas. Due to its special physical and chemical properties, such as low melting point and strong plasticity, lead was also included in alchemy raw materials, hoping to refine medicinal pills with magical effects.
In terms of medical treatment, although the understanding is limited, the ancients found that certain compounds containing heavy metals have special effects on some diseases. For example, lead dan (lead trioxide) has the functions of detoxification, myogenesis, and phlegm falling, and will be used to treat sores, swollen sores, and ulcers that do not close their mouths for a long time. Arsenic compounds are also used to treat some skin diseases or parasitic diseases after specific processing. However, the ancients did not fully realize that long-term or excessive use of these heavy metal drugs will bring serious toxic and side effects.
In terms of process production, the amalgam process uses the property that mercury can dissolve a variety of metals to form alloys, which is used in processes such as gilt. First, mercury and gold form amalgam, which is applied to the surface of the utensil, heated to evaporate the mercury, and the gold is firmly attached to the utensil, which can make the surface of the utensil beautiful and wear-resistant. Lead was also used in ancient coinage and the production of ceramic glazes. The hardness and melting point of alloys can be adjusted in coinage, and the melting point of glazes can be reduced in ceramic glazes, making the glaze brighter.
However, it needs to be made clear that although these heavy metals and their compounds had certain uses in ancient times, they also brought many potential hazards to the health of the ancients. For example, long-term use of mercury and lead pills caused chronic poisoning, causing mental disorders, organ damage and other problems. With the development of the times, people's awareness of its hazards has deepened, and modern society has tried to avoid contact and use of these harmful substances to the human body.

The water of Fuhai, rivers, and rivers has different properties, and it involves a lot in the chemical industry. The sea, which is in the sea, contains a lot of water, mainly chlorinated, such as water, water, water, etc. Its color may be white or slightly gray, and the taste is mostly crystalline. The nature of the sea, in the context of tides, is easy to absorb moisture and deliquescence, because of the water it contains.
The water of rivers and rivers originates from mountains, rivers and streams, and is formed by aggregation. It is clear, contains less water, and is more soluble in carbonate, sulfuric acid, etc. The color of river water is often the land and vegetation in the basin, or clear or clear. The taste of river water is light and close to the taste of water, but if it is polluted, the taste of water breeds.
As for its carboxylic acid, this material is very special. Carboxylic acid is acidic, and it can cause the opposite of neutralization, and the water is in the raw phase. Its acidity is weak, depending on its molecule, such as the property of the carboxyl group. If there is a absorber group, the acidity is increased.
The melting of carboxylic acids is special, because the molecule can form alcohol, so it is high in alcohol with carbon. Its solubility is also high, and the carboxylic acid of low carbon can be miscible with water, because the carboxylic group can form water; and the high carbon group, because the proportion of the carboxylic group increases, the solubility decreases.
And the chemical activity of carboxylic acids, such as esterification reaction, alcohol under acid catalysis, ester production water, this reaction is very important in the fields of fragrance, chemical synthesis, etc. It can also generate original reactions, specific reactions, and can be used to synthesize alcohols. Its general properties are widely used in chemical industry, chemical industry, food industry, etc.

The chemical properties of halogen elements such as mercury, bromine, and astatine are quite stable.
Halogen elements are in the seventh main group of the periodic table of elements, and the outermost layer of their atoms has seven electrons. In addition, the electron configuration of the layer makes halogen elements have a strong tendency to electrons, so they are usually highly oxidizing. Take chlorine as an example, it meets sodium metal, that is, reacts rapidly to form sodium chloride, which is a common salt component.
Mercury is liquid at room temperature and pressure, with a silver-white metallic luster, and its chemical properties are relatively stable. It is not easy to react quickly with common substances such as oxygen at room temperature. Mercury can dissolve many metals and form amalgam, which is often used in ancient alchemy and metallurgy.
Bromine is the only non-metallic element that is liquid at room temperature, with a dark reddish-brown and pungent odor. Bromine is chemically active and can react with many metals and non-metals, but its activity is slightly less than that of chlorine.
Astatine is a radioactive element and is extremely rare. Due to its radioactivity, the study of the chemical properties of astatine is quite difficult. However, according to the periodic law of elements, the chemical properties of astatine should be similar to other halogen elements, but due to the influence of radioactivity, its stability may be worse than that of other halogen elements.
Overall, although halogen elements are chemically active, they are still stable under certain conditions. The stability of mercury comes from its electronic configuration, which makes the interaction between mercury atoms unique, and it is difficult to react with common substances under normal conditions. Although halogen elements such as bromine and astatine are active, they can form stable compounds in the presence of strong reducing agents or in specific environments, showing certain stability.

Mercury bromide red, also known as red mercury, is an organic mercury disinfectant preservative. The preparation method is as follows:
1. ** Preparation of raw materials **: It is necessary to prepare phthalic anhydride, resorcinol, mercury and other raw materials. Phthalic anhydride and resorcinol are mixed in a specific ratio. This is the key material for the initiation of the reaction, which lays the foundation for the subsequent generation of mercury bromide.
2. ** Condensation reaction **: After mixing phthalic anhydride and resorcinol, a condensation reaction occurs at an appropriate temperature and catalyst. This process requires precise control of temperature and reaction time. Generally, the temperature is controlled within a certain range, and the duration also has corresponding requirements, so that the two can be condensed to form a fluorescent yellow matrix structure. This step is an important stage in the construction of the molecular skeleton of mercury bromide red.
3. ** Mercurization reaction **: The condensation product is then mercurized with mercury. Mercury and the condensation product interact under specific reaction conditions, and mercury atoms are integrated into the molecular structure. This reaction has strict environmental requirements, such as pH and purity of the reaction system, which must be strictly controlled, otherwise the purity and yield of the product will be affected.
4. ** Bromination reaction **: After the mercury is completed, the bromination reaction is carried out. Through a specific bromination reagent, bromine atoms are introduced into the molecule at a specific location to generate mercury bromide red. The bromination reaction also requires precise control of the reaction parameters to ensure that bromine atoms are accurately integrated into the target location and ensure the quality of the product.
5. ** Purification and refining **: After the reaction, the resulting product contains impurities and needs to be purified and refined. Recrystallization, extraction and other methods are often used to remove impurities and improve the purity of mercury bromide red. After this step, the finished product of mercury bromide red that meets Quality Standards can be obtained.
Preparation of mercury bromide red requires strict follow of the process, precise control of the reaction conditions to ensure product quality and yield.

I look at your question, but I am inquiring about the price of mercury and mercury salts in the market. Mercury, also known as mercury, is a liquid metal with unique properties. Mercury salts are salt compounds formed from mercury.
However, mercury and mercury salts are both toxic and harmful to the environment and human health. In today's world, the production, trade and use of mercury and mercury salts are strictly regulated in all countries. It is common in the market, and it is rare to see free trade in mercury and mercury salts.
In the past, the price of mercury may have changed depending on the time, the place of origin, and the purity. However, the use of mercury is limited, and it is mostly used in specific industries, scientific research, and other fields, and strict regulations need to be followed.
The same is true of mercury salts. Due to their toxicity, they cannot be traded at will without permission. If they are obtained through specific channels of legal compliance, their price is also complex and changeable, depending on their type, purity, and market supply and demand.
Although you want to know their price, they are dangerous and should not be involved lightly. Everyone should abide by the law and do not touch forbidden areas for the sake of asking for a price, so as to protect their own safety and the environment.