In "Tiangong Kaiwu", there are many kinds of alum, and the alum related to halogenated salts is mainly "bile alum", which is widely used.
Bile alum, also known as blue alum, is a key material in the field of metallurgy. Take the smelting of copper as an example, bile alum plays an indispensable role. Because of the copper element in bile alum, ancient people can extract copper from bile alum through ingenious chemical methods. This process usually dissolves bile alum in water first, and then puts it into the solution with active metals such as iron. Due to the difference in metal activity, iron can replace copper from the bile alum solution to obtain metallic copper. This method was widely used in the smelting of ancient copper, which greatly promoted the production of copper alloy products such as bronze and brass, and was of great significance in the casting of various utensils and weapons.
Furthermore, bile alum also has its uses in medicine. It has certain medicinal value and can be used as medicine to treat diseases. However, bile alum is toxic and should be used with extreme caution. In traditional Chinese medicine prescriptions, bile alum is sometimes used in small amounts to treat diseases such as wind and phlegm congestion, laryngeal paralysis, and epilepsy. Its principle may be based on the special chemical properties of bile alum to produce regulation and treatment effects on human diseases.
In addition, in the printing and dyeing industry, bile alum also contributes. It can be used as a mordant. In the process of fabric dyeing, bile alum can make the dye better adhere to the fabric, improve the dyeing effect, make the dyed color more vivid and lasting, and help the printing and dyeing industry improve product quality, enrich the variety of fabric colors, and meet the needs of people for the beauty of clothing and other fabrics.

Mercury and chlorine are all chemical substances, and their physical properties are different.
Mercury, which is often a liquid under normal conditions, is the only liquid gold. Its color is white, with golden light, excellent fluidity, and high density, 13.59 g/cm ³, so it can be burned on the surface of objects, and it is easy to form small mercury beads. The melting temperature of mercury is -38.87 ° C, and the boiling temperature is 356.6 ° C. The melting phase of mercury is narrow. In addition, mercury has good performance and is very good, and it is useful in fields such as transportation. In addition, mercury has certain properties, and it often evaporates slowly. This evaporation is toxic and poses a great health hazard to humans.
As for mercury chloride and calomel, it is often deposited in white crystals or powders. Its density is 7.15 g/cm ³, which is slightly smaller than that of mercury. Mercury chloride melts at 400 ° C, decomposes under pressure, and has a low solubility in water. It is insoluble, inert, and highly qualitative. It is not easy to react to most chemical substances. Because of its low toxicity, it was used in the past in the field of chemical production, such as in the field, but it has been used less now because of its deep understanding. The outer layer of mercury chloride is white, and the outer layer of the white liquid of mercury is clear.

Mercury is very cold and toxic. It is a liquid at room temperature, and the silver light flows, like a snake swimming. It is volatile and can gradually accumulate in the air. If inhaled, it is often harmful to health, brain and viscera.
Chloroethane is a colorless gas, and it can also be stored as a liquid in a specific container. Its properties are more active and flammable. The smell is slightly sweet and pungent. The boiling point is quite low, and it is highly volatile. When it evaporates, it can cause the surrounding temperature to drop sharply. This property is often used in medical cryopathy.
Mercury is relatively stable in chemical properties due to its unique liquid metal properties. However, it will also react with strong oxidants to form mercury salts and other compounds. And mercury can dissolve many metals to form amalgam, which is occasionally used in ancient metallurgy and alchemy.
In chloroethane, carbon is connected to chlorine and hydrogen. Due to the strong electronegativity of chlorine atoms, the electron cloud in the molecule is unevenly distributed. It can undergo a substitution reaction, such as co-heating with an aqueous solution of sodium hydroxide, the chlorine atom can be replaced by a hydroxyl group to form ethanol; if it is co-heated with an alcohol solution of sodium hydroxide, an elimination reaction occurs to form ethylene. In the field of organic synthesis, ethyl is often introduced as an alkylation agent.
The chemical properties of the two are significantly different. Mercury is a metal element, with its liquid state and toxicity, and the formation of amalgam with metals. Chloroethane is an organic compound, active in organic reactions, and its low boiling point, volatile and reactive characteristics in organic synthesis make it play a role in different fields.

Mercury, a highly toxic metal, is liquid at room temperature and volatile. There are various methods for the synthesis of mercury haloethane, which are described in detail below.
One is the reaction between haloethane and mercury salts. Take an appropriate amount of haloethane, place it in a clean reactor, inject a mercury salt solution, such as a mercury nitrate solution, and stir the reaction at a specific temperature and pressure. Because the halogen atom of haloethane is active and can be substituted with mercury ions, the alkyl group of haloethane is then connected to mercury to form mercury haloethane. This process requires precise temperature control. If the temperature is too high, side reactions will occur frequently, resulting in impure products; if the temperature is too low, the reaction will be slow and take a long time.
The second is to use Grignard's reagent as a medium. The Grignard's reagent for halogenated ethane is first prepared. The halogenated ethane and magnesium chips are co-placed in anhydrous ether to initiate a reaction to obtain alkyl magnesium halide. After that, mercury-containing compounds are slowly added, such as mercury chloride. Alkyl magnesium halide has strong alkyl nucleophilicity, which attacks mercury atoms, and the halogen ions leave to form mercury halide. This path requires strict reaction environment and requires absolute anhydrous and oxygen-free, otherwise the Grignard's reagent is easy to decompose and cause the reaction to fail.
Third, it can be indirectly synthesized by the reaction of alcohol and mercury halide. Alcohol is properly treated, such as reacting with halogenating agents to form halogenated hydrocarbons, and then the hal The presence of alkali can accelerate the dissociation of the halogen atoms of halogenated hydrocarbons, making it easier to combine with the mercury atoms of mercury halide to form mercury halide. This process step is slightly complicated, but the raw materials are easy to obtain and the operation is relatively simple.
All synthesis methods have their own advantages and disadvantages. In practice, the choice should be made carefully according to the availability of raw materials, the conditions of equipment, and the purity requirements of the product.

Mercury cyanide needs to be strictly observed in both storage and storage, so as to prevent accidental production and ensure human safety and environment from pollution.
Mercury is the most toxic gold, and the first time it is stored, it is sealed. Special containers, such as thick-walled glass or gold materials, need to be used, and have good corrosion resistance. Containers must be sealed to prevent mercury evaporation and exposure. In terms of storage environment, it is appropriate to keep low evaporation, dryness and good ventilation. The evaporation density of mercury is higher than that of air, and it is easy to accumulate at low levels, so it is especially important to pass. At the same time, the storage of sources of fire, pollution and oxidation, because it encounters specific problems or causes dangerous reactions. In addition, there are clear warnings to prevent people from approaching.
Cyanide is a drug, and the storage requirements are very high. It needs to be stored in the waste drug, and the room is solid and has the functions of fire prevention, explosion-proof and anti-explosion. The department needs to have a perfect degree and degree control system to maintain the environment. Cyanide cannot be combined with acid, oxidation, etc., because it is easy to produce toxic cyanide when it encounters. And the manager is well-versed in the characteristics of cyanide and emergency measures.
Mercury should be used according to the phase method, and the combined tools should be used. If the road needs to use a tank, and do a good job of preventing leakage and shock. On the way to the road, the whole process should not be delayed without authorization. The same product for cyanidation should follow the standard process, and it is necessary to apply to the Ministry of Public Security for approval. The product should be used in real time, and other items should not be mixed. The road should be shipped in advance to avoid densely populated areas and sensitive areas. Once there is a leak in the process, it will immediately report an emergency case, evacuate the crowd, seal it, and deal with it by the staff.