Products Description of Aluminum Hydroxide CAS# 21645-51-2
Aluminum Hydroxide, also known as aluminium trihydrate (ATH), is an amphoteric inorganic compound with molecular formula Al(OH)₃ and molecular weight 78.00. It appears as white fine amorphous powder and is nearly odorless. It is practically insoluble in water and ethanol, but soluble in strong mineral acids and strong alkaline solutions. Its density is 2.42 g/cm³ at 20°C. It decomposes upon heating above 300℃, releasing water and forming alumina.
This material features non-toxicity, good flame-retardant and smoke-suppressing performance. It is widely used as halogen-free flame retardant for plastics, rubber and composite materials. Different particle size grades are available to meet diverse industrial and pharmaceutical requirements.
Aluminum Hydroxide Chemical Properties
| Product Name: | Aluminum hydroxide |
| Synonyms: | alcoac30bf;alcoac330;alcoac333;alugel;alumigel;aluminahydrated;aluminicacid;Aluminiumhydrate |
| CAS: | 21645-51-2 |
| MF: | AlH3O3 |
| MW: | 78 |
| EINECS: | 244-492-7 |
| Product Categories: | INORGANIC & ORGANIC CHEMICALS;PHARMACEUTICALS;Inorganics;Essential Chemicals;Reagent Grade;Routine Reagents;metal hydroxide |
| Melting point | 300℃ |
| Boiling point | 2980℃[at 101 325 Pa] |
| density | 2.42 g/cm3 at 20 °C |
| bulk density | ~90g/100 mL |
| vapor pressure | <0.1 hPa (20 °C) |
| refractive index | Average refractive index: 1.57-1.59 |
| storage temp. | Store at +5°C to +30°C. |
| solubility | 0.0015g/l |
| form | colloidal suspension |
| color | White |
| Specific Gravity | 2.42 |
| Odor | Odorless |
| PH Range | >7 |
| PH | 8-9 (100g/l, H2O, 20℃)(slurry) |
| Water Solubility | insoluble |
| Crystal Structure | Monoclinic |
| Merck | 14342 |
| Solubility Product Constant (Ksp) | pKsp: 32.89 |
| Exposure limits | ACGIH: TWA 1 mg/m3 |
| Dielectric constant | 2.2（Ambient） |
| Stability: | Stable. Incompatible with strong bases. |
| LogP | -1.380 (est) |
| EPA Substance Registry System | Aluminum hydroxide (21645-51-2) |
Product Application of Aluminum Hydroxide CAS# 21645-51-2
Flame-Retardant Field：Aluminum hydroxide is a commonly adopted inorganic flame retardant incorporated into plastics, rubber, textiles and other materials. Upon thermal decomposition, it absorbs heat and releases water vapor to deliver flame-retardant and smoke-suppressant performance, hence improving the fire resistance of host materials.
Pharmaceuticals Sector：It acts as an antacid for gastric-acid neutralization. It is utilized to treat hyperacidity and gastric ulcers and helps alleviate gastric discomfort.
Chemical Raw Material：It functions as a critical precursor for manufacturing aluminum oxide, aluminum sulfate, polyaluminum chloride and other aluminum-containing compounds.
Other Uses：It works as a gentle abrasive in toothpaste for dental cleaning. Within the paper industry, it improves water resistance and printability. In cosmetic formulations, it serves as an additive featuring oil-absorbing and pH-adjusting capabilities.
