Difference between revisions of "Aluminium oxide"
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{{Chembox | {{Chembox | ||
| − | | Name =Aluminium oxide | + | | Name = Aluminium oxide |
| Reference = | | Reference = | ||
| − | | IUPACName = | + | | IUPACName = Aluminium(III) oxide |
| PIN = | | PIN = | ||
| SystematicName =Aluminium oxide | | SystematicName =Aluminium oxide | ||
| − | | OtherNames = | + | | OtherNames = Aloxide<br>Aloxite<br>Alumina<br>Alundum<br>Corundum<br>Ruby<br>Saphire |
| − | + | ||
| − | + | ||
| − | + | ||
| − | + | ||
| − | + | ||
<!-- Images --> | <!-- Images --> | ||
| − | | ImageFile = | + | | ImageFile = rubies.jpg |
| + | | ImageCaption = Samples of ruby, a red variant of corundum. | ||
| ImageSize = | | ImageSize = | ||
| ImageAlt = | | ImageAlt = | ||
| Line 49: | Line 44: | ||
| 3DMet = | | 3DMet = | ||
| Abbreviations = | | Abbreviations = | ||
| − | | SMILES = | + | | SMILES = [Al+3].[Al+3].[O-2].[O-2].[O-2] |
}} | }} | ||
| Section2 = {{Chembox Properties | | Section2 = {{Chembox Properties | ||
| AtmosphericOHRateConstant = | | AtmosphericOHRateConstant = | ||
| − | | Appearance = | + | | Appearance = White solid |
| − | | BoilingPt = | + | | BoilingPt = |
| − | | BoilingPtC = | + | | BoilingPtC = 2977 |
| BoilingPt_ref = | | BoilingPt_ref = | ||
| BoilingPt_notes = | | BoilingPt_notes = | ||
| Line 62: | Line 57: | ||
| HenryConstant = | | HenryConstant = | ||
| LogP = | | LogP = | ||
| − | | MolarMass = | + | | MolarMass = 101.96 g/mol |
| − | | MeltingPt = | + | | MeltingPt = |
| − | | MeltingPtC = | + | | MeltingPtC = 2072 |
| MeltingPt_ref = | | MeltingPt_ref = | ||
| MeltingPt_notes = | | MeltingPt_notes = | ||
| + | | Odor = Odorless | ||
| pKa = | | pKa = | ||
| pKb = | | pKb = | ||
| − | | Solubility = | + | | Solubility = Insoluble |
| − | | SolubleOther = | + | | SolubleOther = Reacts with halogenic acids and alkali<br>Insoluble in organic solvents |
| Solvent = | | Solvent = | ||
| − | | VaporPressure = | + | | VaporPressure = ~0 mmHg |
}} | }} | ||
| Section3 = {{Chembox Structure | | Section3 = {{Chembox Structure | ||
| − | | Coordination = | + | | Coordination = Octahedral |
| − | | CrystalStruct = | + | | CrystalStruct = Trigonal, hR30, space group = R3c, No. 167 |
| MolShape = | | MolShape = | ||
}} | }} | ||
| Line 82: | Line 78: | ||
| DeltaGf = | | DeltaGf = | ||
| DeltaHc = | | DeltaHc = | ||
| − | | DeltaHf = | + | | DeltaHf = −1675.7 kJ/mol |
| − | | Entropy = | + | | Entropy = 50.92 J·mol<sup>−1</sup>·K<sup>−1</sup> |
| HeatCapacity = | | HeatCapacity = | ||
}} | }} | ||
| Line 93: | Line 89: | ||
}} | }} | ||
| Section6 = {{Chembox Hazards | | Section6 = {{Chembox Hazards | ||
| − | | AutoignitionPt = | + | | AutoignitionPt = Non-flammable |
| − | | ExploLimits = | + | | ExploLimits = Non-explosive |
| − | | ExternalMSDS = | + | | ExternalMSDS = [https://www.docdroid.net/xD4eXUw/aluminium-oxide-sa.pdf.html Sigma-Aldrich] |
| − | | FlashPt = | + | | FlashPt = Non-flammable |
| LD50 = | | LD50 = | ||
| LC50 = | | LC50 = | ||
| − | | MainHazards = | + | | MainHazards = Irritant |
| NFPA-F = | | NFPA-F = | ||
| NFPA-H = | | NFPA-H = | ||
| Line 110: | Line 106: | ||
| OtherFunction = | | OtherFunction = | ||
| OtherFunction_label = | | OtherFunction_label = | ||
| − | | OtherCompounds = | + | | OtherCompounds = [[Boron trioxide]] |
}} | }} | ||
}} | }} | ||
| − | Aluminium oxide is chemical compound of [[ | + | '''Aluminium oxide''' or '''alumina''' is the chemical compound of [[aluminium]] and [[oxygen]], with chemical formula '''Al<sub>2</sub>O<sub>3</sub>'''. It's the most common and stable form of the aluminium oxides. Aluminium oxide occurs naturally in it's crystalline alpha phase as mineral '''corundum'''. |
| − | Aluminium oxide occurs naturally in it's crystalline alpha phase as mineral '''corundum'''. | + | |
==Properties== | ==Properties== | ||
===Chemical=== | ===Chemical=== | ||
| + | Aluminium oxide will react with sodium hydroxide to form sodium aluminate. | ||
===Physical=== | ===Physical=== | ||
| − | Aluminium oxide is very hard | + | Aluminium oxide is a white solid compound, insoluble in water and solvent, but will dissolve in non-oxidizing acids. It is odorless and it's very hard (9 Mohs scale). It's an electrical insulator. |
| − | It's electrical insulator. | + | |
==Availability== | ==Availability== | ||
| − | Aluminium oxide is often present in sandpapers, you can also buy it from mineral collectors as | + | Aluminium oxide is often present in sandpapers, you can also buy it from mineral collectors as corundum or gemstones like ruby or sapphire. Certain smartphones have colorless transparent protective sheet of synthetic corundum. |
| + | |||
| + | Heating elements also contain alumina powder which acts as an insulator for the resistance wiring. | ||
==Preparation== | ==Preparation== | ||
Aluminium oxide is a product of [[thermite]] reaction: | Aluminium oxide is a product of [[thermite]] reaction: | ||
| − | |||
| − | + | :M<sub>2</sub>O<sub>3</sub> + 2 Al → Al<sub>2</sub>O<sub>3</sub> + 2 M | |
| + | This reaction also gives various aluminates, and separating the alumina from the slag is complicated and may not worth it. | ||
| − | + | A much better and simpler method involves the dehydration of aluminium hydroxide, which can be obtained by precipitating an aluminium salt with sodium or potassium hydroxide. | |
| + | : Al(NO<sub>3</sub>)<sub>3</sub> + 3 NaOH → Al(OH)<sub>3</sub> + 3 NaNO<sub>3</sub> | ||
| + | |||
| + | Another route involves adding an acid to sodium aluminate, forming sodium salt of said acid and aluminium oxide/hydroxide. Excess NaOH can be added after the addition of the acid to prevent the formation of aluminium salts. Sodium aluminate itself is obtained from the reaction of sodium hydroxide and aluminium metal. | ||
| + | |||
| + | : NaOH + Al → NaAlO<sub>2</sub> + H<sub>2</sub>O + H<sub>2</sub> | ||
| + | : NaAlO<sub>2</sub> + H<sup>+</sup> + NaOH → Na<sup>+</sup> + Al(OH)<sub>3</sub> | ||
| + | |||
| + | Aluminium oxide can be obtained by calcinating aluminium hydroxide between 500-850 ºC: | ||
| + | |||
| + | : 2 Al(OH)<sub>3</sub> → Al<sub>2</sub>O<sub>3</sub> + 3 H<sub>2</sub>O | ||
| + | |||
| + | ==Projects== | ||
| + | *Make aluminium salts | ||
| + | |||
| + | ==Handling== | ||
===Safety=== | ===Safety=== | ||
| + | No special handling is necessary, though it's recommonded to avoid inhaling in in powdered form. Aluminium oxide isn't flamable or explosive. | ||
===Storage=== | ===Storage=== | ||
| + | Storage in closed bottles is adequate. | ||
===Disposal=== | ===Disposal=== | ||
| + | Aluminium oxide could be safely dumped with normal trash or spilled out in a soil. | ||
==References== | ==References== | ||
<references/> | <references/> | ||
===Relevant Sciencemadness threads=== | ===Relevant Sciencemadness threads=== | ||
| − | [[Category: | + | *[http://www.sciencemadness.org/talk/viewthread.php?tid=61897 Making Relatively Pure Alumina] |
| + | |||
| + | [[Category:Chemical compounds]] | ||
| + | [[Category:Inorganic compounds]] | ||
[[Category:Aluminium compounds]] | [[Category:Aluminium compounds]] | ||
| + | [[Category:Oxides]] | ||
| + | [[Category:Materials unstable in acidic solution]] | ||
| + | [[Category:Materials unstable in basic solution]] | ||
[[Category:Solids]] | [[Category:Solids]] | ||
[[Category:Minerals]] | [[Category:Minerals]] | ||
| + | [[Category:Ceramic materials]] | ||
Latest revision as of 23:30, 20 March 2020
 Samples of ruby, a red variant of corundum.
| |
| Names | |
|---|---|
| IUPAC name
Aluminium(III) oxide
| |
| Systematic IUPAC name
Aluminium oxide | |
| Other names
Aloxide
Aloxite Alumina Alundum Corundum Ruby Saphire | |
| Identifiers | |
| Jmol-3D images | Image |
| |
| Properties | |
| Al2O3 | |
| Molar mass | 101.96 g/mol |
| Appearance | White solid |
| Odor | Odorless |
| Density | 3.95–4.1 g/cm3 |
| Melting point | 2,072 °C (3,762 °F; 2,345 K) |
| Boiling point | 2,977 °C (5,391 °F; 3,250 K) |
| Insoluble | |
| Solubility | Reacts with halogenic acids and alkali Insoluble in organic solvents |
| Vapor pressure | ~0 mmHg |
| Thermochemistry | |
| Std molar
entropy (S |
50.92 J·mol−1·K−1 |
| Std enthalpy of
formation (ΔfH |
−1675.7 kJ/mol |
| Hazards | |
| Safety data sheet | Sigma-Aldrich |
| Flash point | Non-flammable |
| Related compounds | |
| Related compounds
|
Boron trioxide |
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
| Infobox references | |
Aluminium oxide or alumina is the chemical compound of aluminium and oxygen, with chemical formula Al2O3. It's the most common and stable form of the aluminium oxides. Aluminium oxide occurs naturally in it's crystalline alpha phase as mineral corundum.
Contents
Properties
Chemical
Aluminium oxide will react with sodium hydroxide to form sodium aluminate.
Physical
Aluminium oxide is a white solid compound, insoluble in water and solvent, but will dissolve in non-oxidizing acids. It is odorless and it's very hard (9 Mohs scale). It's an electrical insulator.
Availability
Aluminium oxide is often present in sandpapers, you can also buy it from mineral collectors as corundum or gemstones like ruby or sapphire. Certain smartphones have colorless transparent protective sheet of synthetic corundum.
Heating elements also contain alumina powder which acts as an insulator for the resistance wiring.
Preparation
Aluminium oxide is a product of thermite reaction:
- M2O3 + 2 Al → Al2O3 + 2 M
This reaction also gives various aluminates, and separating the alumina from the slag is complicated and may not worth it.
A much better and simpler method involves the dehydration of aluminium hydroxide, which can be obtained by precipitating an aluminium salt with sodium or potassium hydroxide.
- Al(NO3)3 + 3 NaOH → Al(OH)3 + 3 NaNO3
Another route involves adding an acid to sodium aluminate, forming sodium salt of said acid and aluminium oxide/hydroxide. Excess NaOH can be added after the addition of the acid to prevent the formation of aluminium salts. Sodium aluminate itself is obtained from the reaction of sodium hydroxide and aluminium metal.
- NaOH + Al → NaAlO2 + H2O + H2
- NaAlO2 + H+ + NaOH → Na+ + Al(OH)3
Aluminium oxide can be obtained by calcinating aluminium hydroxide between 500-850 ºC:
- 2 Al(OH)3 → Al2O3 + 3 H2O
Projects
- Make aluminium salts
Handling
Safety
No special handling is necessary, though it's recommonded to avoid inhaling in in powdered form. Aluminium oxide isn't flamable or explosive.
Storage
Storage in closed bottles is adequate.
Disposal
Aluminium oxide could be safely dumped with normal trash or spilled out in a soil.
References
Relevant Sciencemadness threads
Categories:
- Chemical pages without CAS Registry Number
- Articles without EBI source
- Chemical pages without ChemSpiderID
- Chemical pages without DrugBank identifier
- Articles without KEGG source
- Articles without InChI source
- Articles without UNII source
- Articles containing unverified chemical infoboxes
- Chemical compounds
- Inorganic compounds
- Aluminium compounds
- Oxides
- Materials unstable in acidic solution
- Materials unstable in basic solution
- Solids
- Minerals
- Ceramic materials
