This compound is called "mercury bromide red", commonly known as "red potion". In ancient prescription books, it may be given another name for its properties, ingredients or uses. The following is explained in the classical form of "Tiangong Kaiwu":
Mercury bromide red is also a medical disinfectant today. Its color is red, its nature is mild, and it has a good effect on skin trauma.
The ancient Fang family, or because of its red color, it is called "red medicine". Gaidan sand was a precious thing in ancient times. It is red in color and has medicinal uses. This agent is also red in color and has healing power, so it is named "red medicine".
And because it is common in trauma disinfection, and the skin is used, the color is red and obvious, just like the red color added to the bloodstain, and there are also people who call it "blood covering pill". "Blood" means that it is used in the place where the trauma blood comes out, "covering" shows the state of smearing and covering, and "Dan" should be its red color, which is the image and its use.
In addition, mercury bromide red contains mercury, which was commonly used in alchemy in ancient times, also known as "mercury", plus its red color, or it is called "mercury red spirit". The word "spirit" indicates the efficacy of its disinfection and healing, and this name not only contains the essence of the ingredients, but also shows its strange effect.
Although today's science is clear, the name of the ancient times also shows the wisdom of the predecessors in observing and observing objects, which can be passed on to future generations, and can also be used as a medicine and culture for archaeologists.

The chemical properties of a substance are also related to its characteristics and changes in chemical reactions. In the description of "Tiangong Kaiwu", although the writing is simple, it also contains many wonderful solutions to the chemical properties of substances.
Take gold as an example, it has excellent stability. "Where the gold is the heaviest, each copper square inch weighs one or two, silver according to the rules, the inch weighs three coins; silver square inch weighs one or two, gold according to the rules, the inch weighs two coins." The density of gold also shows that its chemical properties are stable from the side, and it is not easy to react with ordinary substances, so it can be stored for a long time without decay. In the natural environment, over time, gold often exists in a elemental state, rarely oxidized or combined with other substances, due to its strong chemical stability.
Looking at iron, its chemical properties are more active than gold. "Where iron is meristem and ripe, it is raw when it is not fried when it is baked, and ripe when it is fried. When it is raw and ripe, it is made into steel." Iron is prone to react with oxygen and water in the air and rust, which is a common chemical change. However, the ancients also knew to use its characteristics to change its carbon content by stir-frying and refining, so as to obtain iron products with different properties. Pig iron has high carbon content and is brittle; wrought iron has low carbon content and is more flexible; while steel is the sum of raw wrought iron phase, and its properties are between the two. This is due to the active chemical properties of iron, which can combine or decompose with elements such as carbon under specific conditions.
On sulfur again, although its chemical properties are not detailed in the book, in the production of gunpowder, "where gunpowder, sulfur is pure yang, and nitrate is pure yin", it can be seen that sulfur is oxidizing. Gunpowder is mixed in proportion with saltpeter, sulfur, and charcoal. When ignited, sulfur reacts violently with saltpeter and charcoal, releasing a large amount of heat and gas. This all depends on the chemical properties of sulfur.
All of these, although "Tiangong Kaiwu" does not analyze the chemical properties of substances in detail in today's chemical terms, it uses the description of various processes and phenomena to enable future generations to glimpse the cognition and application of the chemical properties of substances by the ancients.

This compound has a wide range of uses and is useful in many fields.
In the field of medicine, this compound is often used as a raw material for pharmaceuticals. It can help doctors make good medicines for symptoms and treat people's diseases. For certain diseases, it is necessary to use this compound as a base and through exquisite craftsmanship, it can become a special medicine, which can relieve the suffering of patients and save them from pain. According to its characteristics, doctors skillfully prepare drugs to give full play to the best effect and protect the health of the world.
In the chemical industry, this compound is also an important material. It can be used to synthesize various fine chemicals to make the quality and performance of chemical products better. Or participate in the preparation of special materials, and through complex reactions, generate materials with unique properties to meet the needs of industrial production and scientific and technological research and development. Such as manufacturing tough and durable new materials, which can be used in machinery manufacturing, aerospace and other important places to improve the performance and lifespan of equipment.
In agriculture, this compound also has its functions. It can be made into fertilizers and pesticides to help crops thrive and resist pests and diseases. Rational application of fertilizers containing this compound can provide crops with the nutrients they need, make plants lush and fruits fruitful; when made into pesticides, it can remove pests, kill pathogens, ensure the harvest of crops, and contribute to the stable foundation of people's lives.
In the path of scientific research and exploration, this compound is even more helpful. Scientists use their unique characteristics to carry out various experiments and research to explore the unknown and open up new fields of science. Or in the research and development of new materials and the exploration of new reactions, this compound is a key factor, leading scientific research to a new height and contributing to human cognition and transformation of the world.

The physical properties of a certain utensil are related to its shape, quality and properties. According to the "Tiangong Kaiwu", each utensil has its own state, and the physical properties are also different. Try to say it.
First describe its shape. Everything is tangible, square or round, long or short, flat or thick. Metals such as gold, silver, copper, and iron, after forging and casting, can be formed into knives, swords, kettles, tripods, etc. For knives, the blade is thin and the body is narrow, which is conducive to cutting; for tripods, the belly is round and standing on its feet, which is used for cooking. The difference in shape is related to its use, and it also shows the difference in physical properties.
Second on its quality. Quality, the body of things. Such as earth and stone, heavy and strong, can build walls and houses; the genus of wood and bamboo, light and tough, can make utensils and weave things. In metal terms, the metal is soft, yellow and luster, good ductility, can be made of gold foil, jewelry; iron is hard, gray-black, high strength, and is mostly used for equipment and agricultural implements. Different qualities determine the physical properties of utensils such as strength and conduction.
Then talk about its properties. Sex, the characteristics of things are also. Such as saltpeter, which is dry and explodes in case of fire, is the key to gunpowder; mercury, which is liquid at room temperature, flows easily and is toxic. Another example is water, which can carry or capsize a boat. It is a liquid, with fluidity and solubility, and can transfer heat and sound. This is the physical property of the characteristics of the utensils.
And the physical properties of the utensils also change in different environments. If iron is in a dry place, it is not easy to rust; if it is in a humid place, it is prone to rust, its quality is gradually damaged, and its strength is also reduced. Another example is wood, which burns in case of fire and turns into ashes; if soaked in water for a long time, it will also decay.
The physical properties of utensils are diverse, and the shape, quality, properties and environmental effects. As recorded in "Tiangong Kaiwu", although it is described in ancient law, the wonders of the physical properties of utensils can still be explored and comprehended, providing many enlightenments for the way of making and using utensils in later generations.

Now there are those who ask what the method of synthesis is, and this is a delicate question. Looking at "Tiangong Kaiwu", it is detailed and meticulous in the description of various skills, which can be used to find the way of synthesis.
The synthesis of all things, the first heavy raw material. Such as metallurgy, must choose good ore. When iron is formed, iron ore is first taken. This stone is bred between mountains and rivers and is rich in iron. After it is mined, it is put into the furnace. The furnace is built with fire-resistant materials and can withstand high temperatures. In the furnace, add coke. Coke is made from coal, which is strong and can generate high temperatures. Iron ore and coke are placed in the furnace together, and the blast is used to support combustion. When the iron ore is heated, the quality of the iron melts gradually, and the impurities float up, removing its dross, and the molten iron can be obtained. When the molten iron cools, it becomes iron.
It is also like the method of making porcelain. Choose the soil first, and the soil must be delicate and pure, such as kaolin. After taking the soil, knead it with water to make mud. The craftsman shapes the mud by hand or with the help of utensils, which can be in the shape of bowls, plates, bottles, etc. After shaping, it is fired in the kiln. The kiln is also particular about using firewood as fuel, and the heat must be accurately controlled. At first, it is baked slowly over a low fire, so that the moisture of the utensils is gradually lost, and then the fire burns fiercely. When it reaches a certain temperature, the porcelain clay changes qualitatively, and the surface forms enamel, which is smooth and bright. After this process, the porcelain is formed.
Then it is like the art of papermaking. Take green sandalwood skin, bamboo, etc. as raw materials. First soak the raw materials in lime water, which is the retting material. The lime water can decompose the raw materials and separate the fibers. After a period of time, remove the raw materials, wash them, and then pounded them in the stone mortar to make the fibers finer. After that, put the fibers in a sink, add water and stir them into pulp. Gently scoop the bamboo curtain in the pulp, so that the fibers are evenly attached to the bamboo curtain. This is papermaking. Copy it, squeeze out the water, then remove the paper, stick it in the "alley" and dry it. After drying, the paper is finished.
All these synthetic methods require craftsmen to be attentive, follow their path, and follow their rules to get a good product. The choice of raw materials, the sequence of processes, and the control of heat are all related to the advantages and disadvantages of the synthetic product.