2 Iodo 5 Bromopyridine

As mentioned in "Tiangong Kaiwu", the main use of the sink covers many aspects.
First, it is used for irrigation of farmland. Ancient farming relied on water for nourishment, and the fields were vast, and the distribution of water needed to be even. The sink can lead the water of rivers and streams to the fields, meandering to the fields, so that the rice, wheat and millet can be moistened. In times of drought, the sink is the key to saving the crops, which can lead the water source from the distance to the dry fields, avoid the worries of farmers, and ensure the abundance of the five grains.
Second, it is also indispensable for the operation of the workshop. Like a smelting and casting place, the metal melt needs to be condensed and formed, and the tank can hold cold water, so that the caster can be quickly cooled to determine its shape and quality. In the dyeing workshop, after the fabric is dyed, it needs to be washed with water to clear the color. The sink stores water, which is convenient for raccoon washing, so that the color is fresh and lasting.
Third, in the water supply of daily life, the sink also contributes. In the market, it is not easy for the people to get water, and the sink can store water for backup, for cooking, washing, sprinkling, etc. Even if the waterways in the city are occasionally blocked, or the water is exhausted due to drought, the water storage in the sink can also solve the emergency and maintain the normal order of people's livelihood.
Fourth, in the construction of buildings, the sink is also useful. To build houses, wet mud is needed as a bonding material, and the sink stores water, which is combined with the soil to form mud to lay bricks and stones, making the house strong. In addition to fire prevention, the sink is often placed in the house to store water for safety. In case of disaster, water can be used to put out the fire and reduce the spread of the fire.
All these, it can be seen that the use of the sink is related to agriculture, industry, people's livelihood, and construction. It is actually an indispensable tool for the life and production of the ancients. It has made outstanding achievements in the survival and development of society.

Mercury is one of the hardware, and its synthesis method has been explored a lot in ancient times. In "Tiangong", there is also a related method.
One of them is the mercury sublimation method of dansha. For dansha, mercury sulfide is also. The dansha is placed in a dense container and added. The dansha is decomposed, the sulfur and mercury are separated, and the mercury is dissolved. When cooled, it condenses in the upper part of the container, and mercury can be collected to obtain mercury. This process is controlled by the heat, and the mercury in the fire is easy to dissipate, and the fire is not enough to decompose. As the saying goes: "Where the mercury is raised, stop using the original cinnabar, and use one catty of mercury per liter, use 14." That is, the approximate ratio of mercury in dansha is indicated.
The second is to synthesize mercury from mercury and other gold, and then obtain mercury. Mercury has special properties and can form mercury from more gold, such as gold, gold, etc. First, the mercury gold is formed into mercury, which is dispersed in the gold, forming an alloy-like thing. In addition, mercury is added, and the mercury boiling phase is low. First, it melts and escapes, and then condenses and collects, and then mercury can be obtained again. This method is often used to extract gold from stone, use mercury gold and other gold to form mercury, separate gold, and then recover mercury.
In addition, there are also other mercury-containing raw materials, which can be processed in a series to make them into the shape of mercury, and then mercury can be obtained by the above-mentioned methods of raising and dividing. Therefore, the method of synthesizing mercury requires careful operation, either according to the characteristics of the raw materials, or controlled by the heat, or by the chemical process, to obtain this special thing.

Mercury is strong and poisonous, and its characteristics are obvious in various things.
Its shape and quality are liquid metals under normal circumstances. It is bright like silver and flows indefinitely. Although it has the luster of metal, it is not like the solid state of other gold. It is smooth to the touch, can be aggregated or dispersed, and cannot be separated.
In terms of its chemical properties, mercury is active and has a unique reaction. It can quickly combine with sulfur to synthesize mercury sulfide, which is a common change in ancient alchemy, and it is also a method for removing mercury poisoning. It can also form amalgam with many metals. If it encounters gold, gold can dissolve in mercury. This property is widely used in gold panning and ancient gilting processes.
The toxicity of mercury, especially need to be warned. Its poison can penetrate into the body through breathing, skin seepage and diet, damaging the organs, brain and nerves. Ancient alchemists, many people fell ill or even died due to mercury poisoning. In the past, the emperor of Qin prayed for longevity, so that alchemists refined alchemies, and the pills often contained mercury, or caused their bodies to gradually decline.
Mercury is found in nature and often exists in minerals such as cinnabar. The ancients picked it and refined it, seeing its wonderful changes, or used it for medicine, but due to unknown toxicity, it was also wrong.
Looking at the nature of mercury, although it has strange uses, it is highly toxic. When using it, you should be cautious and not forget its risks because of its wonders. You must use scientific methods to avoid harm and seek profit.

Mercury is a highly toxic substance with unique chemical properties. Mercury is liquid at room temperature, and its color is silvery white, shining like a mirror, so the ancients often called it "mercury".
Mercury is relatively weak in chemical activity, but it can be fused with a variety of metals to form amalgam. The formation of this amalgam is mostly a process of physical mixing, not chemical changes. For example, when gold and mercury meet, they can form gold amalgam, and the ancients used this property to refine gold.
Mercury is volatile and can form mercury vapor in the air, which is highly toxic. If inhaled, mercury will accumulate in the body, seriously damaging the nervous system, digestive system and urinary system. Many ancient alchemists suffered from serious illness or even death due to long-term exposure to mercury.
Mercury can react with oxygen. Under heating conditions, mercury can combine with oxygen to form mercury oxide. In this reaction, mercury increases from zero to positive divalent, reflecting its reductivity. Mercury oxide can be decomposed when heated to regenerate mercury and oxygen, a reversible process.
Mercury can also react with some acids. For example, mercury can react with nitric acid to form mercury nitrate and corresponding reduction products. When reacted with concentrated nitric acid, the products are mercury nitrate, nitrogen dioxide and water; when reacted with dilute nitric acid, mercury nitrate, nitric oxide and water are formed. These reactions indicate that mercury can be oxidized by nitric acid under certain conditions.
Although mercury is a metal, it is difficult to react with alkalis, which is different from the chemical properties of most metals. Due to the relatively weak metal activity of mercury, it is difficult to replace and other reactions in alkaline solutions.
In short, the chemical properties of mercury are unique and complex. Although ancient people knew and used it, its toxicity also caused many hazards to humans, which needs to be treated with caution.

In today's market, the quality of two to five percent of oil is different, and it is generally caused by the quality.
The first words are material, if it is high-quality, its surface is clean and bright, and it can also prevent corrosion. Such oils, or high, are also often found in about five percent. And clay is durable, but compared with the quality of the utensils, the price is high, or it is above and below.
Furthermore, the quality of the workmanship is also poor. Those who have been carefully carved by skillful craftsmen, their bodies may be engraved with auspicious oils, or with flowers and tender oils. Such workmanship adds a lot of color to the oil, and the price is not cheap, or four or five. If it is rough and rough, it is only necessary to use it, and it is not beautiful to study, or not to use it in two or three sizes.
Also, the size and shape of the product also affect the size. The large product has a lot of oil capacity, long-lasting lighting, and if the shape is out of the mind, such as the shape and sound of the product, it can attract people from the green, and it is also high, often ranking in the four or five. And ordinary small products, the shape is ordinary, and it is very strange. It is mostly in two or three sizes.
And the supply and demand of the market also affects the price. If the demand for oil in a certain section increases greatly, and the craftsman's production is limited, the price must be high; on the contrary, if the supply is limited, the craftsman can sell it quickly, or reduce the price in order to obtain it, and the oil of the second section can also be obtained. Moreover, the oil price in the market is high, and the general factors such as material quality, workmanship, size and supply and demand are affected, so the height is high and low.