Pyrazine, 2-bromo-

Mercury is a highly toxic liquid metal, and its physical properties are very unique.
The color of mercury is as shiny as silver, and it is often in a flowing state. It is like smart mercury and has a dazzling luster. Its melting point is very low, only -38.87 ° C. At this temperature, it solidifies into a solid state. The boiling point is 356.6 ° C. Most of the normal environment is liquid. This property makes mercury at different temperatures, and its shape is variable, which is quite wonderful.
The density of mercury is extremely high, about 13.59 grams per cubic centimeter, far exceeding that of common liquids. If placed on mercury, due to the disparity in density, many objects can float on the surface of mercury, which is quite unique.
Mercury has excellent fluidity. Due to its strong cohesion, it can flow easily in the liquid state, resembling smart and invisible water, and can penetrate into tiny gaps, making it difficult to be bound.
In addition, mercury has good electrical and thermal conductivity. In circuits, it can conduct current; in heat transfer scenarios, it can also quickly transfer heat, and has applications in many fields.
The surface tension of mercury is also large. On a plane, mercury droplets often aggregate into round beads, which are not easy to spread out. It is like a natural ball, which is also one of its remarkable physical properties.
However, it is necessary to keep in mind that although mercury has unique physical properties, it is highly toxic, and exposure to or inhalation of mercury vapor can cause serious damage to human health. When using it, it is necessary to exercise caution.

Mercury is a highly toxic metal with unique and complex chemical properties, which are recorded in many ancient books and traditional knowledge.
Mercury is liquid at room temperature, which is one of its remarkable characteristics. Its melting point is very low, only -38.87 ° C, and its boiling point is not high, 356.6 ° C. This unique physical state has attracted everyone's attention in ancient times. In "Huainan Zi · Topographic Training", there are "nine fields in the sky, nine states in the earth, nine mountains in the soil, nine plugs in the mountains, nine abyss in the swamp, eight levels in the wind, and six grades in water... Eight catties of red copper, seven catties of tin, nine catties of lead, and three catties of mercury. This medicine of Taiyi is also a record." It speaks of the use of mercury in alchemy and other alchemy techniques, and also reflects the ancient people's understanding of its physical properties.
The chemical activity of mercury is in a specific range. It can react with oxygen under heating conditions to generate mercury oxide. "Baopuzi · Jindan" cloud: "Dan sand burns into mercury, and accumulates into Dan sand." The "mercury burned in Dansha" refers to the thermal decomposition of mercury sulfide into mercury and sulfur, and the "accumulation and transformation into Dansha" refers to the reaction of mercury and sulfur to form mercury sulfide, which shows that the ancients have observed and utilized this chemical property of mercury. Mercury can also form amalgams with many metals, which was also applied in ancient times. For example, the ancients used amalgamation to extract metals such as gold and silver.
Mercury compounds are of various kinds and have different properties. For example, mercury chloride is highly toxic, and the ancients or used it for medicine, but the dosage should be extremely cautious; mercury sulfide, that is, Dansha, has a bright color and is not only used for alchemy, but also for pigments.
Although ancient people had some understanding and utilization of the chemical properties of mercury, due to limited understanding, they often ignored its toxic hazards. Today, we are well aware that mercury is extremely harmful to the human body and the environment. When using and handling mercury and its compounds, it is necessary to follow strict scientific regulations to ensure safety.

The method of melting and moulding has been known in ancient times. There are many methods, and the method is often used.
First, the method of mud moulding. First, use the mud mould to engrave the flower and shape, and then seek refinement. Wait for the mould to dry, and then wrap it in mud to form an outer model. The outer model dries, and the mould is left with a gap. This is the cavity of the moulding. The molten gold liquid is injected into the cavity, cold and solidified. Break the outer model, take out the moulding, and trim it a little to get the finished product. This method is used for the shaping of moulding utensils, such as tripods, jue, etc. The green tools of Shang and Zhou are mostly made by this method.
Second, the method of losing the moulding. To form a mold, one mold and one mold of the desired utensils are engraved. Then, the refractory material is applied outside the mold, and it is reused many times to form a hard mold. Add a layer to bake, so that the mold melts and flows out, leaving a hollow cavity. The high-quality molten gold liquid is injected into the cavity and cold-formed. This method can create its fine and high-quality utensils, such as Zeng Hou Yizun, which are exquisite and exquisite, and can be used without loss.
Third, the gold mold manufacturing method. Using gold as the mold, its durability is high, and it can be used many times. The mold needs to be added first, so that the gold liquid can be injected easily, and the amount of gold can be improved. This method is used for a large number of raw-shaped utensils, and the efficiency is high. However, the cost of manufacturing is high, and the requirements for manufacturing are strict.

The general method of manufacturing, each has its own shortcomings. The craftsman weighs the advantages and disadvantages according to the shape, use, quantity and other factors of the utensils, and is good and good. Only then can we achieve exquisite utensils and inherit the delicacy of manufacturing techniques.

Mercury is used in a wide range of fields. In the field of medicine, there were many applications in the past. Ancient healers used mercury to refine medicine, hoping that it could achieve miraculous effects. The cover mercury has special properties, and after refining, it may be able to make medicine have different effects. However, the toxicity of mercury was not known at that time, so there were many people who were harmed by the use of mercury.
In the realm of craftsmanship, mercury also has its uses. When casting a weapon, use mercury to prepare an alloy, or it can make the material of the weapon better. Such as swordsmiths, or use mercury to change its steel to make the sword tougher and sharper. And in the process of glass firing and other processes, mercury can help it to prepare colors and make the color of the glass colorful.
Furthermore, in the process of alchemy, mercury can be said to be very important. The alchemists wanted the medicine of longevity, and they used mercury to refine medicinal pills. They believed that mercury could be refined into a miraculous pill, which could prolong life and even become immortals. Therefore, in the room of alchemy, mercury was often placed in a prominent place, used day and night for alchemy. However, as a result, many medicinal pills not only failed to make people live forever, but because of the toxicity of mercury, the body of those who took the pill was damaged, and even their lives were endangered.
As for folk life, there may also be the shadow of mercury. For example, the technique of making mirrors may be assisted by mercury to make the mirror surface brighter and brighter. Although its application seems to be convenient for life, the potential harm of mercury is also hidden in it, and it has become apparent for a long time.

In today's market, the price of weights varies according to the supply and demand of the market, the quality of materials, and the fineness of workmanship.
The supply and demand of the city is the most important. If there are many people who ask for weights at times, and there are many who use them, the price will increase; if there are few who need them, the goods will be stored in the market, and the price will be suppressed. If the demand for weights increases greatly when the weighing apparatus is repaired and used more often, merchants will see an opportunity, or raise the price.
The quality of the material is also related to the price. The quality of the first-class material is firm and durable, and the price will be higher than that of ordinary materials. If the metal is made of fine iron, it will be of high quality and expensive than that made of miscellaneous copper or inferior stone. Moreover, the craftsmanship of the mound can make the weight accurate, and the price of such Seiko products is not cheap. Shoddily made, although the cost is low, but the accuracy is insufficient, and the price cannot be compared with that of the Seiko.
There are regional differences, and the prices of the four cities are different. In prosperous places, the goods and goods are convergent, and the materials are easy to obtain, but the price may be slightly higher due to taxes and rents; in remote places, the materials are rare and the work is scarce, and the price may be expensive because of it.
The market is impermanent, and the price is also uncertain. Or due to natural disasters and man-made disasters, the source of materials is blocked, and the price of the weight also changes accordingly. Therefore, if you want to know the market price of the scale, you should judge the situation, observe supply and demand, identify materials, and measure the region in order to know its approximate price.