Element 56: Barium

1、 Elemental Introduction Barium,
The alkaline earth metal element, with the chemical symbol Ba, is located in Group IIA of the sixth period of the periodic table. It is a soft, silver white luster alkaline earth metal and the most active element in alkaline earth metals. The element name comes from the Greek word beta alpha ρύς (barys), which means “heavy”.

2、 Discovering a Brief History
Sulfides of alkaline earth metals exhibit phosphorescence, meaning they continue to emit light for a period of time in the dark after being exposed to light. Barium compounds began to attract people’s attention precisely because of this characteristic. In 1602, a shoemaker named Casio Lauro in the city of Bologna, Italy, roasted a barite containing barium sulfate together with flammable substances and discovered that it could emit light in the dark, which aroused the interest of scholars at that time. Later, this type of stone was called polonite and aroused the interest of European chemists in analytical research. In 1774, Swedish chemist C.W. Scheele discovered that barium oxide was a relatively heavy new soil, which he called “Baryta” (heavy soil). In 1774, Scheler believed that this stone was a combination of new soil (oxide) and sulfuric acid. In 1776, he heated the nitrate in this new soil to obtain pure soil (oxide). In 1808, British chemist H. Davy used mercury as the cathode and platinum as the anode to electrolyze barite (BaSO4) to produce barium amalgam. After distillation to remove mercury, a low purity metal was obtained and named after the Greek word barys (heavy). The element symbol is set as Ba, which is called barium.

3、 Physical properties
Barium is a silver white metal with a melting point of 725 ° C, boiling point of 1846 ° C, density of 3.51g/cm3, and ductility. The main ores of barium are barite and arsenopyrite.

4、 Barium is a chemical element with chemical properties.
The chemical symbol Ba, atomic number 56, belongs to the periodic system IIA group and is a member of alkaline earth metals. Barium has great chemical activity and is the most active among alkaline earth metals. From the potential and ionization energy, it can be seen that barium has strong reducibility. In fact, if only considering the loss of the first electron, barium has the strongest reducibility in water. However, it is relatively difficult for barium to lose the second electron. Therefore, considering all factors, the reducibility of barium will decrease significantly. Nevertheless, it is also one of the most reactive metals in acidic solutions, second only to lithium, cesium, rubidium, and potassium.

5.Main compounds
1). Barium oxide slowly oxidizes in air to form barium oxide, which is a colorless cubic crystal. Soluble in acid, insoluble in acetone and ammonia water. Reacts with water to form barium hydroxide, which is toxic. When burned, it emits a green flame and generates barium peroxide.
2). Barium peroxide reacts with sulfuric acid to produce hydrogen peroxide. This reaction is based on the principle of preparing hydrogen peroxide in the laboratory.
3). Barium hydroxide reacts with water to produce barium hydroxide and hydrogen gas. Due to the low solubility of barium hydroxide and its high sublimation energy, the reaction is not as intense as that of alkali metals, and the resulting barium hydroxide will obscure the view. A small amount of carbon dioxide is introduced into the solution to form a barium carbonate precipitate, and excess carbon dioxide is further introduced to dissolve the barium carbonate precipitate and generate soluble barium bicarbonate.
4). Amino barium can dissolve in liquid ammonia, generating a blue solution with paramagnetism and conductivity, which essentially forms ammonia electrons. After a long period of storage, the hydrogen in ammonia will be reduced to hydrogen gas by ammonia electrons, and the total reaction is barium reacting with liquid ammonia to produce amino barium and hydrogen gas.
5). Barium sulfite is a white crystal or powder, toxic, slightly soluble in water, and gradually oxidized into barium sulfate when placed in air. Dissolve in non oxidizing strong acids such as hydrochloric acid to generate sulfur dioxide gas with a pungent odor. When encountering oxidizing acids such as dilute nitric acid, it can be converted into barium sulfate.
6). Barium sulfate has stable chemical properties, and the portion of barium sulfate dissolved in water is completely ionized, making it a strong electrolyte. Barium sulfate is insoluble in dilute nitric acid. Mainly used as a gastrointestinal contrast agent.
Barium carbonate is toxic and almost insoluble in cold water., Slightly soluble in water containing carbon dioxide and soluble in dilute hydrochloric acid. It reacts with sodium sulfate to produce a more insoluble white precipitate of barium sulfate – the conversion trend between precipitates in aqueous solution: it is easy to convert towards a more insoluble direction.

6、 Application Fields
1. It is used for industrial purposes in the production of barium salts, alloys, fireworks, nuclear reactors, etc. It is also an excellent deoxidizer for refining copper. Widely used in alloys, including lead, calcium, magnesium, sodium, lithium, aluminum, and nickel alloys. Barium metal can be used as a degassing agent to remove trace gases from vacuum tubes and cathode ray tubes, as well as a degassing agent for refining metals. Barium nitrate mixed with potassium chlorate, magnesium powder, and rosin can be used to manufacture signal flares and fireworks. Soluble barium compounds are commonly used as insecticides, such as barium chloride, to control various plant pests. It can also be used for refining brine and boiler water for electrolytic caustic soda production. Also used for preparing pigments. The textile and leather industries use it as a mordant and a matting agent for artificial silk.
2. Barium sulfate for medical use is an auxiliary medication for X-ray examination. Odorless and tasteless white powder, a substance that can provide positive contrast in the body during X-ray examination. Medical barium sulfate is not absorbed in the gastrointestinal tract and does not cause allergic reactions. It does not contain soluble barium compounds such as barium chloride, barium sulfide, and barium carbonate. Mainly used for gastrointestinal imaging, occasionally used for other purposes of examination

7、 Preparation method
The industrial production of metallic barium is divided into two steps: the production of barium oxide and metal thermal reduction (aluminum thermal reduction). At 1000-1200 ℃, metallic barium can be obtained by reducing barium oxide with metallic aluminum, and then purified by vacuum distillation. Aluminum thermal reduction method for producing metallic barium: Due to different ingredient ratios, there may be two reactions for aluminum reduction of barium oxide. The reaction equation is: both reactions can only produce a small amount of barium at 1000-1200 ℃. Therefore, a vacuum pump must be used to continuously transfer barium vapor from the reaction zone to the cold condensation zone in order for the reaction to continue to move to the right. The residue after the reaction is toxic and needs to be treated before disposal