What is the difference between nitrogen and argon protection in chemical reactions?

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Both nitrogen and argon are inert gases. It’s just that nitrogen is not as inert as argon; I wonder what the differences are between using nitrogen and argon for protection in chemical reactions? Let’s take a look together. Physical properties of nitrogen: Elemental nitrogen is a colorless and odorless gas under normal conditions. Its density at standard conditions is 1.25 g·dm-3. At standard atmospheric pressure, nitrogen turns into a colorless liquid when cooled to -195.8°C, and it becomes a snow-like solid when cooled further to -209.86°C. Nitrogen has very low solubility in water; at normal temperature and pressure, about 0.02 volumes of nitrogen dissolve in 1 volume of water. It is a gas that is difficult to liquefy. Its solubility in water is very low; at 283 K, one volume of water can dissolve approximately 0.02 volumes of N2. At extremely low temperatures, nitrogen liquefies into a white liquid; further reduction in temperature results in the formation of a white crystalline solid. Nitrogen available on the market is usually stored in black gas cylinders. Chemical properties: The molecular orbital diagram of a nitrogen molecule is such that it is the three pairs of electrons that contribute to bonding, resulting in the formation of two π bonds and one σ bond. They contribute nothing to bonding; the bonding and antibonding energies roughly cancel each other out, and they are equivalent to lone electron pairs. Due to the triple bond N≡N present in the N2 molecule, it possesses high stability; breaking it down into atoms requires 941.69 kJ/mol of energy. The N2 molecule is the most stable among known diatomic molecules. Uses of nitrogen: Nitrogen is primarily used in the production of ammonia, from which fertilizers, nitric acid, and other substances are manufactured. Ammonia is also an important raw material for synthetic fibers such as nylon and acrylic fiber, as well as for synthetic resins and synthetic rubbers. Due to its chemical inertness, nitrogen is commonly used as a shielding gas. To prevent certain materials from being oxidized by oxygen when exposed to air, filling grain silos with nitrogen helps keep the grain from molding or sprouting, allowing it to be stored for a long time. Liquid ammonia can also be used as a cryogenic agent. Argon Chemical properties: Argon is a monatomic, chemically inert gas. It does not react with other elements or compounds. Although there are reports that a few compounds of red and other noble gases have been prepared, it can be considered that such research has only scientific significance. For all practical applications, every attempt to combine complexes into common types of compounds has failed. These efforts include treating argon with oxidants and reductants. Argon is stable because all of its electrons are fully paired, and there are no bonding orbitals. Uses of argon: Argon is a rare gas that is widely used in industry today. It is highly unreactive; it cannot burn nor does it support combustion. In the aircraft manufacturing, shipbuilding, nuclear energy industry, and machinery industry sectors, argon is often used as a welding shielding gas when welding special metals such as aluminum, magnesium, copper and their alloys, as well as stainless steel, in order to prevent the welded parts from being oxidized or nitrided by air. In metal smelting, oxygen and argon blowing are important methods for producing high-quality steel; the amount of argon consumed per ton of steel produced is 1–3 m3. Furthermore, argon is also used as a shielding gas in the smelting of special metals such as titanium, zirconium, and germanium, as well as in the electronics industry. Argon, which makes up 0.932% of the air, has a boiling point between that of oxygen and nitrogen. Its concentration is highest in the middle section of the tower in air separation units, and this fraction is known as the argon fraction. By separating oxygen and nitrogen while extracting the argon fraction for further separation and purification, an argon by-product can also be obtained. For full-low-pressure air separation units, generally 30% to 35% of the argon in the processed air can be obtained as a product (modern processes have enabled the argon extraction rate to be increased to over 80%) ； For medium-pressure air separation units, since the expanded air enters the lower column, it does not affect the distillation process in the upper column, allowing an argon recovery rate of around 60%. However, small air separation units have a low total amount of air processed, which limits the amount of argon that can be produced; whether it is necessary to install an argon extraction unit depends on the specific circumstances. Argon is an inert gas and poses no direct harm to the human body. However, if waste gas is generated after industrial use, it is highly harmful to the human body and can cause conditions such as silicosis and eye damage. Although it is an inert gas, it is also a asphyxiating gas; inhaling large amounts of it can cause asphyxiation. The production area must be well-ventilated, and technicians working with argon should undergo regular annual health checks to ensure their good physical condition. Argon is non-toxic in itself, but it can cause asphyxiation at high concentrations. There is a risk of asphyxiation when the argon concentration in the air exceeds 33%. When the argon concentration exceeds 50%, severe symptoms occur; at concentrations of over 75%, death can occur within a few minutes. Liquid argon can damage the skin, and contact with the eyes can cause inflammation. In chemistry, certainly not limited to organic chemistry, an inert gas atmosphere such as nitrogen or argon is required for certain purposes, such as to isolate oxygen or water vapor. Those with better conditions can use a glove box; those with less favorable conditions can use a three-way system as a substitute. The simplest option is to use a balloon attached to a three-way fitting, which can also work directly. There is also a choice as to whether nitrogen or argon should be used in the reaction; apart from the fact that argon is more expensive than nitrogen, there are also chemical reasons for this choice. High-purity argon is more inert than high-purity nitrogen. Common metal-organic reactions such as Suzuki coupling can be carried out without problems under high-purity nitrogen. When metals or metal-organic compounds react with nitrogen, high-purity argon is required; for example, reactions involving lithium metal must take place under high-purity argon, as nitrogen reacts with lithium. As long as your reactants or products do not react with nitrogen, it’s fine to use nitrogen even if the literature uses argon.