Pyridine 4 Bromo 2 Iodo

4-2. Those who are rational in nature have special characteristics of the earth. The earth is as solid as gold and stone, and the sound is clear and clear, such as the ring, and its shape is straight, and the four corners are clear, just like the utensils carved by heaven.
As far as its density is concerned, it is thick and heavy, and placed in the palm of the hand. It feels heavy, and the things that are normal are not good enough. This is due to the density of the parts. Its color is either ancient, with the mulberry taste of history, or the white light, like the frost and snow, the light is beautiful, and the uncommon things can be compared.
Its performance is also unique, and it is not like other things are suddenly cold and sudden. This characteristic makes it able to maintain the degree of stability in a specific environment. In addition, its performance is good. If it is used, it will circulate well, just like the water of a river, and it will be blocked.
Even in terms of its qualitative quality, it is also excellent. It is not perishable, and it is not invaded by acid. It stands tall like the walls of a city. This is why it can survive in the world for a long time. In short, 4-2% of the material reason is rational, which integrates the characteristics of solidity, thickness, color, quality, and transformation. It is also a wonder of heaven.

Mercury is cold and heavy in nature. Its shape is like water like silver, which flows and is easy to move. It is a highly toxic substance.
Mercury has a metallic luster. At room temperature, it is a liquid state, smooth in texture, and highly volatile. This is its physical characteristic. As for chemical properties, it is particularly unique.
Mercury is less active, but it can also react when it encounters strong oxidants, such as concentrated nitric acid and concentrated sulfuric acid. Mercury is mixed with concentrated nitric acid to synthesize mercury nitrate, and reddish-brown nitrogen dioxide gas escapes. Its shape is like a red cloud rising, which is terrifying to watch. When heated with concentrated sulfuric acid, mercury sulfate is produced, and sulfur dioxide gas escapes at the same time, which smells pungent.
Mercury in the air is stable at room temperature, but when heated to more than 300 degrees, it combines with oxygen and turns into mercury oxide. The color of this mercury oxide is bright red, like the color of Dansha.
Mercury meets sulfur powder, and the two quickly combine to produce mercury sulfide. This reaction is very wonderful, even at room temperature, it can proceed spontaneously. Mercury sulfide is stable in nature and dark in color. After sublimation, it can turn into vermilion color, which is the common cinnabar.
Mercury interacts with metals to form amalgams. Many metals can form amalgams with mercury, such as gold, silver, zinc, etc. The formation of amalgams may change the original properties of metals, or be a method for extracting metals.
The toxicity of mercury cannot be ignored. Mercury and its compounds are all highly toxic. If the human body inhales mercury vapor or accidentally ingests mercury-containing substances, mercury toxicity can easily invade the nervous, digestive and urinary systems, causing serious diseases and even life-threatening. Ancient alchemists used mercury in alchemy, and many people died from pill poisoning, all of which were caused by unknown mercury toxicity.

4-2 The most common methods of synthesis are water quenching, fire quenching, and melting.
The method of water quenching has been known in ancient times. Take the stone and place it in the fire, calcined until it is transparent, and the surface of the stone is damaged due to its high temperature. Immediately, cold water is added, and the stone is cracked and broken due to the cold. In this case, the required material is initially divided into the stone, and then processed, washed and other processes can be improved. As in ancient times, this method of water quenching is often used to make the stone initially decompose and obtain rough billets.
The method of fire is especially important for heat control. Stones are placed in crucibles, fueled by charcoal, coal and other fuels, and then added. Different rocks require different temperatures, such as stoneware, and need to be heated at a medium temperature to make the stoneware melt one by one. The stoneware either floats on the surface, or sinks to the bottom, which can be skimmed or removed. When the stoneware is completely melted and condensed, the pure gold can be obtained. This fire method is used for metallurgical multi-metal stoneware.
The method of melting is to help the power of the stoneware. Take a suitable stoneware, and the stoneware is co-placed in a container. The biochemical reaction of the stoneware makes the required materials dissolve in the liquid, but insoluble. It can be separated. It can be extracted from the liquid by means of precipitation, steaming, etc. In ancient times, some rare gold was often extracted by this method, using the characteristics of gold.
Of these three, water quenching is mainly based on physical transformation, fire is mainly based on high melting, and melting is essential. Each has its own use of stone, and each has its own exquisite method. It is an important synthesis method for ancient smelting, lifting and other processes.

"Tiangong Kaiwu" says: "Tetrabromodiphenyl ether has a wide range of uses and is used in various fields.
In the field of electronic appliances, it is often used as a flame retardant. In electrical appliances, the wiring is complicated and flammable. Adding tetrabromodiphenyl ether to plastics and other materials can prevent the spread of fire and ensure the safety of electrical appliances. Its flame retardant ability allows electrical appliances to delay combustion when an accidental fire starts, providing an opportunity for rescue and personnel evacuation, and reducing fire damage.
In the textile industry, it is also used. Fabrics treated with tetrabromodiphenyl ether can obtain flame retardant properties. This is of great significance for fabrics used in public places, such as cinema seat covers, hotel curtains, etc. Where people are densely packed, fire prevention is essential. The treated fabric can ensure that in the event of fire danger, the fire will not quickly start a prairie fire and protect the safety of everyone.
In the field of chemical materials, tetrabromodiphenyl ether is an important intermediate. Based on it, a variety of chemicals can be prepared. Through chemical methods, by virtue of its molecular structure properties, various materials with different functions have been derived, which has the power to promote the development of the chemical industry.
However, although it has a wide range of uses, its potential impact on the environment and health should also be considered. When using it, it is necessary to weigh the pros and cons, follow the scientific method, and minimize the benefits and drawbacks to achieve the purpose of sustainable development.

Today, there are 40% paint erdou. How is the market price?
The price of paint in Guanfu City is often measured by quality and quantity. In ancient times, paint was a precious thing, mostly taken from sumac trees. It was not easy to harvest, and it was also complex to make, so its price was high.
If you want to know the exact price of this 40% paint erdou, you need to know the market conditions at that time. If it is a good year, everything is going well, the output of paint is quite abundant, and the demand of users has not increased sharply, the price may be slightly flat. On the contrary, if in a disaster year, the lacquer tree is damaged, the production of lacquer is greatly reduced, and there are many places where the world uses lacquer, such as painters, decorative wood, etc., the demand does not decrease but increases, and the price will rise.
Furthermore, the 40% lacquer is the content of impurities in the lacquer. 40% lacquer, compared with pure lacquer, is slightly inferior in quality, but it is also useful. If we take the usual practice of the city at that time, the price of pure lacquer is geometric, and the 40% lacquer is reduced according to the quality. Let a bucket of pure lacquer be worth ten taels, and the price of this 40% lacquer, or because of its quality, is 70-80% of pure lacquer, that is, a bucket is worth about six or seven taels of gold.
However, the market is not constant, the price is not fixed, or due to differences in regions, the supply and demand of the north and the south are different, and the price is also different. Or due to the conspiracy of merchants, the hoarding of goods is strange, and the price can also fluctuate. Therefore, in order to know the exact market price of this 40% paint Erdou, it is necessary to carefully examine the local merchants' market and supply and demand status at that time to obtain an accurate number.