The aluminum oxide (A the 2 O 3 of chemical formula), also called alumina, alumina, corundum or aluminum trioxide, is a metal oxide produced from the reaction between a metal and oxygen (O). It is also known as a basic oxide, due to the ease of forming hydroxides when they react with water.
This is so because the aluminum found in the IIIA family of the periodic table has a tendency to give up the electrons of the last energy level. This tendency is due to its metallic character and its low electronegativity (1.61 on the Pauling scale), which give it electropositive properties and make it a cation.
In contrast, oxygen is a nonmetal and is more electronegative due to its high electronegativity (3.44 on the Pauling scale). For this reason it tends to stabilize the electronic energy of its last level by accepting electrons, which makes it an anion.
The bonds formed are strong bonds, which gives the aluminum oxide great resistance. In nature, aluminum is not found natively like gold, silver, copper, sulfur, and carbon (diamond).
This means that aluminum is not combined with any other element; This metal is mixed with oxygen, forming compounds such as corundum or emery, which are highly resistant and abrasive compounds.
Chemical formula and structure
Molecular Formula: Al 2 O 3
It also shows acidic properties when reacting with bases:
Although water is not formed in this reaction, it is considered acid-base because Al 2 O 3 neutralizes NaOH. Therefore, Al 2 O 3 is classified as an amphoteric oxide because it exhibits both acidic and basic properties.
In the formation of alkenes and cycloalkenes, one of the most used forms in the industrial and laboratory field is through the dehydration of alcohols.
For this, alcohol vapor is circulated over a hot alumina or aluminum oxide (Al 2 O 3) catalyst; in this case it is considered a Lewis acid.
Applications
- Alumina is used in industry to obtain aluminum.
- It is used as a ceramic material due to its high resistance to corrosion at high temperatures and wear.
- It is used as a thermal insulator, especially in electrolytic cells.
- It has the ability to absorb water, which makes it suitable for use as a drying agent.
- Used as a catalytic agent in chemical reactions
- Due to its high thermal stability, it is used as an oxidant in chemical reactions carried out at high temperatures.
- Prevents the oxidation of the cathode and anode terminals in an electrolytic cell.
- Due to its great hardness and resistance, it is used in dentistry for the manufacture of teeth.
- It is a good electrical insulator in the spark plugs of vehicles that work with gasoline.
- It is widely used in ball mills for the preparation of ceramics and enamels.
- Due to its light weight, in engineering processes it is used to make airplanes.
- Due to its high boiling point, it is used to make kitchen implements such as pans and refractory.
- It is used in the instrumentation of thermal testing machines.
- In the electronics industry it is used in the manufacture of passive components for electrical interconnection and in the manufacture of resistors and capacitors.
- It is used in the manufacture of fillers for welding.
- Aluminum oxide is used for coating titanium oxide (pigment used for paints and plastic papers). This prevents reactions between the environment and this type of pigment, which prevents it from decomposing or oxidizing.
- It is used as an abrasive in toothpastes.
- It is used in hemodialysis.
- As an additive in the food industry, as it is used as a dispersing agent.
- It is an antiperspirant agent in deodorants.
- Aluminum oxide has been used as an orthopedic material. Because it is an inert and porous material, it is suitable for use in this type of implant. These implants allow fibrovascular growth, so fibroblasts and osteoblasts proliferate rapidly in this material.
- The bioceramic implant is made with alumina. It is lightweight and has a very well interconnected uniform pore structure. The microcrystalline structure is smoother than the rough surface. It has less flammability after a postoperative period compared to other materials used for implants.
- Aluminum oxide flakes produce reflective effects inside used car paints.
- In some refineries, aluminum oxide is used to convert the toxic gases of hydrogen sulfide into elemental sulfur.
- The form of alumina called activated alumina has great benefits in the treatment of wastewater such as that of aquifers due to its ability to adsorb many pollutants harmful to the environment, as well as to filter residual material that is dissolved in the water and that is larger than the pore size of alumina sheets.
References
- Chang, R; Chemistry, 1992, (fourth edition), Mexico. McGraw-Hill Interamericana de México.
- Pine.S; Hendrickson, J; Cram, D; Hammond, G (1980), Organic Chemistry, (fourth edition), Mexico, McGraw-Hill de México
- Kinjanjui, L., (sf) Properties & Uses of Aluminum Oxide, It Still Work, Recovered, itstillworks.com
- Panjian L., Chikara, O., Tadashi, K., Kazuki, N., Naohiro, S., "and" Klaas de G., (1994). The role of hydrated silica, titania, and alumina in inducing apatite on implants. Journal of Biomedicals materials Research. Volume 18, pp. 7-15. DOI: 10.1002 / jbm.820280103.
- Complete Information Guide to Rocks, Minerals, & Gemstones., Mineral.net., Recovered, minerals.net
- LaNore, S., (2017), Physical Characteristics of Aluminum Oxide, Sciencing, Recovered, sciencing.com