Facts about iodine

Iodine can sublimate into purplish red gas. Iodine is an indispensable element in life. It plays an important role in the production of thyroid hormones in humans and all vertebrates. Iodine deficiency can lead to serious health problems, including goiter, mental disability and cretinism.

As a pure element, iodine is a purple-black nonmetal with solid luster under standard conditions. It is easy to sublimate (from solid to gas while bypassing liquid) and release purple vapor. Although technically it is non-metallic, it has certain metallic properties. "kdspe" and "kdsps" iodine are classified as halogens, which are a subset of chemically active elements (group 17 in the periodic table), and they exist in the environment, not pure elements. Other halogens include fluorine (f), chlorine (cl), bromine (br) and statins (at). The word halogen means "producing salt". When these elements react with metals, they will produce various salts, such as calcium fluoride, sodium chloride (table salt), silver bromide and potassium iodide.

Iodine is the most inactive and electrically charged halogen, which means that it is easy to lose electrons and form positive ions in chemical reactions. It is also the heaviest and least abundant stable halogen. There are 30 known iodine isotopes, but only one is naturally occurring (I- 127).

Iodine has many commercial uses and can be found in various drugs, disinfectants, inks and dyes, catalysts, photographic chemicals and animal feed additives. It plays a particularly prominent role in medicine. For example, iodine compounds are commonly used as disinfection and wound cleaning solutions, and as internal contrast agents in imaging techniques such as computed tomography (CT), radiography and fluoroscopy. The radioisotope iodine-13 1 is also used to treat thyroid cancer.

Iodine is a blue-black shiny solid. According to the data of the World Iodine Association (WIA), trace elements account for about 99.6% of the earth's mass and are a mixture of 32 chemical elements. The remaining 0.4% is divided into 64 elements, all of which are trace. Iodine is one of the most abundant nonmetallic elements on the earth and one of the rarest elements needed for life. Although the content of iodine is not particularly rich, trace amounts of iodine can be found in almost all places, such as water, soil, rocks, plants, animals and human bodies. Seawater has the largest iodine reserves, about 34.5 million tons. However, the concentration is very low, averaging 50 to 60 parts per billion, so direct extraction is not feasible. According to the water treatment scheme of LeNTECH in Denmark, the iodine in the river is less, about 5 ppb. KDSP Most industrial iodine in the world is obtained from natural gas wells in Japan and karic mine in Atacama desert in northern Chile. In the United States, iodine is extracted from deep well brine in northern Oklahoma.

Electronic configuration and elemental properties of iodine. (Greg Robson/Creative Commons， Andrei Marinkas Fauststock) Atomic number (number of protons in the nucleus): 53 atomic symbols (on the periodic table of elements): I atomic weight (average mass of atoms): 126.90447 Density: 4.93g per cubic centimeter at room temperature: solid melting point: 236.7F (165438). Kloc-0/27) In the history, French chemist Bernard Courtois accidentally discovered that iodine Kotova was helping his father to make saltpeter, which was an important component of gunpowder in great demand at that time. At first, he always used wood ash as the source of potassium nitrate needed to make saltpeter. But because of the shortage of wood ash, he began to use seaweed instead. In order to separate sodium and potassium extracts from seaweed, courtois will burn seaweed and wash the ashes with water. Then, sulfuric acid is added to eliminate the remaining waste. After adding too much sulfuric acid at one time, Kutova noticed a purple gas. Later, he found that steam would condense into deep purple crystals on cold surfaces.

At that time, Kutova didn't realize that he had found iodine, but he suspected that it might be a new element. He gave some samples to other scientists to continue their research, and finally proved that this is indeed a new element. The French chemist Joseph Louis Guy Wojciech Luczak named it iode (ioeidē ? comes from Greece and means "Violet"). Although courtois was not the person who named iodine, he was still considered as the first person to separate iodine. 183 1 year, he won the Montion Prize of the Royal Academy of Sciences for his work, but unfortunately, he never benefited from this discovery? 1924, Michigan sold the first batch of iodized salt. Before that, most people living in coastal areas could get a lot of iodine as long as they were close to the ocean and coastal soil. However, people living in inland areas often lack iodine, which leads to a high incidence of goiter. Once the link between iodine deficiency and goiter was established, public health officials began to look for ways to alleviate the problem-eventually leading to the production of iodized salt. Iodine is a good test method for starch, because it turns dark blue when it comes into contact with starch. Photography is the first commercial use of iodine. 1839, louis Daguerre invented a method of making images on metal plates, which is called Daguerre style. Even animals suffer from goiter due to iodine deficiency. It is not uncommon to find goiter in dogs, cows, goats, birds and fish. Iodine is a component of nuclear dust, which is the residual radioactive material falling from the sky after a nuclear explosion. People in radioactive areas are at risk of inhaling or ingesting iodine, which is highly toxic in large doses. Thyroid hormone "KDSPs" iodine is necessary for the synthesis of thyroid hormones thyroxine (T4) and triiodothyronine (T3). T4 and T3 each contain four and three iodine atoms. These hormones are vital to human health, because they control the production and utilization of whole body energy. Iodine deficiency will reduce the production of these hormones, and may lead to goiter and/or mild to severe mental disability. In the case of very serious iodine deficiency in pregnant women, babies may be born with congenital hypothyroidism (or cretinism, now considered as a derogatory term), which is a disease that seriously hinders physical and mental development.

Generally speaking, iodine deficiency affects about 2 billion people around the world and is the main preventable cause. According to Synapse, an Australian brain injury organization, mental disabilities in developing regions of the world. India has the highest prevalence of iodine, with 500 million iodine deficiency, 54 million goiter and 2 million hypothyroidism. According to Cynsey, Kdspe "kdsps", the recommended daily iodine intake of adults in the United States is 150 micrograms (MCG), which is about twice that of pregnant women and lactating women. Marine vegetables and animals, especially seaweed (kelp and kelp), scallop, shrimp and cod, have the highest iodine concentration, but iodine also comes from land food sources, such as plants grown in iodine-rich soil or plants extracted from dairy products and eggs. As long as the diet of cattle and chickens contains enough iodine, cerium and iodine only need trace amounts, and excessive intake will also lead to health problems. People who eat a lot of iodine-rich foods every day, especially kelp and kelp, should ensure that their total daily intake does not exceed the allowable upper limit (UL) of 1 100 micrograms per day (adults 19 years old and above) stipulated by the National Academy of Sciences. According to the report of the world's healthiest food (WHF),

Weak iodine solution is used to treat wounds. (Helga Chirk/Shutterstock) American pathologist David Marine attributed the function of iodized salt to the addition of iodine to salt. From 65438 to 0905, on the first day when Marin became a new doctor in Cleveland, how many people, even dogs, had swollen necks everywhere, which indicated that he had extensive goiter. In fact, this situation is already very common. From the Rocky Mountains to the Great Lakes, and then to the western part of New York, a large area of land is called "goiter area".

After exploring some hypotheses, Marine came empty-handed and began to experiment with iodine supplements. He conducted the first large-scale human experiment on 2000 healthy (goiter-free) students in Akron, Ohio, and gave them a small amount of iodine. A control group of 2000 healthy students did not take any iodine, but they were still closely monitored.

The result is shocking. Of the 2,000 people who received iodine treatment, only 5 eventually developed thyroid diseases, while 475 people in the control group were "KDSP" and "KDSP". Although there were some previous studies on the relationship between iodine and thyroid, Marine finally determined that iodine is indeed an essential element in life, and iodine deficiency can lead to serious health problems. This important discovery of Marine led to the sale of the first iodized salt in the United States in 1924. Shortly after salt iodization, the widespread goiter deficiency has been basically eliminated.

Additional resources

Los Alamos National Laboratory: Iodine Jefferson Laboratory: Royal Chemical Society of Elemental Iodine: Iodine