What Is Boron Oxide?

Boron oxide, chemical formula: B ₂ O ₃ , also known as boron trioxide, is the main oxide of boron. It is a white waxy solid, which generally exists in an amorphous state, and it is difficult to form crystals, but it can also crystallize after high intensity annealing. It is one of the most difficult substances to crystallize. When melted, it can dissolve many alkaline metal oxides to produce glassy borate and metaborate (glass) with characteristic colors, which are used to prepare elemental boron and fine boron compounds. It can also be combined with various oxides to make boron glass, optical glass, heat-resistant glass, instrument glass, glass fiber, and light protection materials with characteristic colors. It can also be used as a refractory olefinic additive and desiccant for paint.

1. Properties: Colorless glass crystal or powder.

2. Density (g / mL, 25/4 ): 1.812 (amorphous), 2.46 (crystalline)

3. Melting point (ºC): 450 ° C (crystallization)

4. Boiling point (ºC, normal pressure): 1860

5. Solubility: soluble in water to become boric acid. Soluble in acid and alkali solution

1. Molar refractive index: None available

2. Molar volume (cm ³ / mol): No available

3. Isometric Zhang Rong (90.2K): No available

4. Surface tension (dyne / cm): None available

5. Dielectric Constant: None available

6. Polarizability (10-24cm ³ ): None available

7. Mass of single isotope: 70.003356 Da

8. Nominal mass: 70 Da

9. Average quality: 69.6202 Da

1. Number of hydrogen-bonded donors: 0

2. Number of hydrogen bond acceptors: 3

3. Number of rotatable chemical bonds: 0

4. Topological molecular polar surface area (TPSA): 43.4

5. Number of heavy atoms: 5

6. Surface charge: 0

7. Complexity: 34.2

8. Number of isotope atoms: 0

9. Determine the number of atomic stereocenters: 0

10. Uncertain number of atomic stereocenters: 0

11, determine the number of chemical bond stereocenters: 0

12. Uncertain number of chemical bond stereocenters: 0

13. Number of covalent bond units: 1 ^[1]

Glassy boron oxide (gB ₂ O ₃ ) is likely to be a network structure formed by the orderly connection of many triangular BO ₃ units through a common oxygen atom. The six-membered ring B ₃ O ₃ is dominant . In this six-membered ring, the boron atom is three coordinated,

1. If used and stored in accordance with the specifications, it will not decompose, and there is no known dangerous reaction. Avoid moisture and humidity.

2. The surface is smooth and tasteless. Soluble in acid, ethanol, hot water, slightly soluble in cold water. It is stable to heat and will not be reduced by carbon when it is white hot, but it can be reduced to elemental boron by alkali metals as well as magnesium and aluminum. When heated to 600 , it can become very viscous liquid. It can strongly absorb water in the air and generate boric acid. It can be combined with several kinds of metal oxides to form boron glass with characteristic colors, which can be completely miscible with the oxides of alkali metals, copper, silver, aluminum, arsenic, antimony and bismuth. poisonous!

3. Boron trioxide produced by crystalline boric acid is a white, porous, slightly sintered substance. It can be easily crushed, but moisture must be removed from the atmosphere during operation. The boron trioxide has high reactivity, and when it comes into contact with water vapor, it will emit heat and make a snoring sound.

It is slightly hazardous to water. Do not allow undiluted or large quantities of products to contact groundwater, waterways or sewage systems. Do not discharge materials into the surrounding environment without government permission.

1. Acute toxicity: The mouse introduced peritoneal LD50: 1868mg / kg, mouse oral LD50: 3163mg / kg, mouse oral LD50: 3163mg / kg.

2, can stimulate the nose, eyes and skin, causing conjunctivitis and rash.

1. Keep the container sealed and stored in a cool, dry place, and ensure that there is good ventilation or exhaust in the work room, and keep away from fire and heat sources.

2. It should be stored separately from acids and must not be mixed. Workers should be protected, and if they accidentally touch the skin and eyes, they should immediately rinse with plenty of water ^[2]

1, atmospheric pressure method

The boric acid is sent into a heating kettle, and the temperature is raised, and the boric acid is slowly dehydrated. When the temperature rises to 107.5 ° C, it becomes metaboric acid (HBO ₂ ), and when it rises to 150 to 160 ° C, it turns into tetraborate (H ₂ B ₄ O ₇ ). Above 650 ° C, a large amount of foam is generated in the melt, and the temperature is finally maintained At 800 1000 , it is dehydrated by burning until the material is red and no more bubbling. The relative density of the melt is 1.52. At this time, the wire drawing machine was started to perform wire drawing, and the temperature was controlled at 700 to 900 ° C. Then, the boron oxide wire on the wire drawing machine is cut with a cutting machine and packed to obtain a boron oxide finished product. The reaction equation is as follows:

1. Determination of silica and alkali in silicate analysis, blowing tube analysis, flux to decompose silicate.

2. Used as a flux when silicate is decomposed, as a dopant for semiconductor materials, heat-resistant glassware and paint refractory additives. It is a raw material for preparing elemental boron and various boron compounds.

3. Used in the production of alloy steel in the metallurgical industry.

4, can be used as a catalyst for organic synthesis, additives for high temperature lubricants and chemical reagents.

5. Used as an analytical reagent, such as a flux to decompose samples, for the preparation of boron. It is also used as a doping source for semiconductor silicon. High-purity reagent for epitaxial and diffusion processes in semiconductor production.