(2B) 2NaOH + 2H2O → 2NaBO2 + 3H2O), and then slowly inject water. With the dissolution and analysis of oxygen oxidation, the solution begins to appear fine bubbles.

Boron will become extremely active at high temperatures. For example, it can be used as a reducing agent to produce a boron thermal reaction similar to the aluminothermic reaction, especially the reaction with copper oxide. Even if the reactant amount is about two grams, the exothermic reaction will be generated. It is still catastrophic. It will not only melt the glass test tube, but also sputter copper vapor everywhere, so almost no one dares to do this in industrial production. A violent reaction will bring terrible consequences if you are not careful.
   Boron can react with almost half of the elements of the periodic table to produce various borides, and the composition of these borides is a nightmare for chemical theoretical research. Taking chromium as an example, the known borides of chromium have Cr4B, Cr2B, Cr3B2, CrB, Cr5B3, Cr3B4, CrB6, CrB2, CrB4, the valence theory becomes elusive when encountering boron.
  If the chemical formula of a substance like molybdenum boride is at least acceptable, then the following compounds are somewhat incomprehensible.

First of all, let's take a look at hexaboride, such as calcium hexaboride. After carefully mixing small particles of calcium metal with boron powder, put them in a quartz tube to evacuate and start heating. At about 1000 degrees Celsius, the two begin to violently The exothermic reaction produces brown-black calcium hexaboride. This compound not only has high hardness, but also has extremely stable chemical properties. First of all, it has super high heat resistance. Put it in the air and bake it with a flame spray gun at high temperature. Roasting, except that the surface layer is slightly whitish due to oxidation, the inside will hardly change. Secondly, calcium hexaboride is not afraid of water and ordinary acids. It is boiled with dilute hydrochloric acid for half a day, except for the iron inside and so on. The impurities are boiled out and the color of the solution turns yellow, but the calcium hexaboride itself remains unchanged. In addition, calcium hexaboride can also absorb neutrons, has a low density and is cheap, so it is also widely used in the nuclear industry. If you have to find something that can react with it, like boron, it is also afraid of nitric acid, but there is basically no reaction when concentrated nitric acid is added to calcium hexaboride at room temperature, and the reaction must be heated before the reaction can proceed, but this is it In terms of , it has surpassed boron.

In fact, not only calcium, boron and rare earth elements such as lanthanum are also hexaborides, and the color of this compound is much brighter, showing a beautiful purple. This purple powder is an excellent material for manufacturing high-temperature cathodes, and traditional Compared with traditional tungsten electrodes, it has low density and long life.
   Next is diboride. If you want to choose a representative from it, it must be titanium diboride. Sponge titanium and amorphous boron are reacted in a vacuum quartz tube, and the combination of the two can be completed after heating to high temperature (Ti +2B→TiB2), although 4 borons are missing, diborides are much higher than hexaborides in terms of melting point and hardness. This is its advantage, but also its disadvantage, because it is hard and has a high melting point, and it is too troublesome to process. Another disadvantage of titanium diboride is that its corrosion resistance is not strong, not to mention strong acids such as nitric acid. Dilute sulfuric acid can also react with it at room temperature, and even titanium diboride can be dissolved in a slightly thicker sodium hydroxide solution, so it is generally used as a tool or coating material.

In fact, there are quite a few diborides, such as zirconium diboride, hafnium diboride, and chromium diboride. They all have common characteristics, such as high hardness, high melting point, and wear resistance, especially chromium diboride. Super corrosion resistance, even strong acids such as nitric acid cannot react with it, and are widely used in turbine blades, rocket nozzles and other industries.
   Although boron is a non-metallic element, it is superior in capturing electrons and can react with many inert substances, such as oxygen group elements and halogens, such as sulfur in the oxygen group, after mixing it with amorphous boron powder, put Heating is carried out in a closed test tube which is evacuated, and the steam formed by heating reacts with boron to form boron sulfide. Also in a vacuumized test tube, iodine, which is the most stable among the halogen elements, can also react with boron in the vapor state, and the purple color fades to form pink boron iodide. Although these reactions are easy to carry out, the generated boron compounds are easily hydrolyzed, which limits their applications.

The really useful borides usually come from ordinary non-metals such as hydrogen, because boron is on the wall of carbon in the periodic table of elements, boron can also form a series of borohydride compounds with hydrogen, these compounds are collectively called boranes, People used to be very eager to get borane, because they are one of the most ideal rocket fuels. However, all boranes are highly toxic, difficult to store, highly corrosive, unstable and bad smell. Know how to use them perfectly.
  However, some complexes of borane, such as borane ammonium complexes, are relatively stable and can be stored in the refrigerator, so they are excellent hydrogen storage substances. After heating, the hydrogen in them can be completely released. Another important compound that can generate boron, boron nitride (2BH NH3+3O2→2BN+6H2O)

There is another simple way to prepare boron nitride in the laboratory, which is to put some boron oxide in the quartz tube, then pass ammonia gas into it and heat it. After the reaction is completed, the glassy boron oxide is washed away, and the test tube White powder can be seen on the wall, which is boron nitride. Boron nitride has many structures, the most famous being hexagonal boron nitride. This white powder has a name called "white graphite" because its structure looks very close to graphite. In addition to being used as a high-temperature lubricant, some high-end cosmetics For example, in liquid foundation or lipstick, it is also used as a filler. In contrast, boron and carbon compounds, the appearance of boron carbide is much worse than that of boron nitride. Like many borides, boron carbide is also a compound with extremely high hardness, which is second only to diamond and cubic in natural substances. Boron Nitride comes in third and is used to make everything from low-end sharpening stones to high-end bulletproof vests