In chemistry, a silicate is a compound containing an anion in which one or more central silicon atoms are surrounded by electronegative ligands. This definition is broad enough to include species such as hexafluorosilicate ("fluorosilicate"), [SiF6]2-, but the silicate species that are encountered most often consist of silicon with oxygen as the ligand. Silicate anions, with a negative net electrical charge, must have that charge balanced by other cations to make an electrically neutral compound.
Silica, or silicon dioxide, SiO2, is sometimes considered a silicate, although it is the special case with no negative charge and no need for counter-ions. Silica is found in nature as the mineral quartz, and its polymorphs.
Sodium silicate is a white solid that is soluble in water, producing an alkaline solution. There are many kinds of this compound, including sodium orthosilicate, Na4SiO4; sodium meta silicate, Na2SiO3; sodium poly silicate, (Na2SiO3)n; sodium pyrosilicate, Na6Si2O7, and others. All are glassy, colorless and dissolve in water.
Sodium silicate is stable in neutral and alkaline solutions. In acidic solutions, the silicate ion reacts with hydrogen ions to form silicic acid, which when heated and roasted forms silica gel, a hard, glassy substance.
| Fire: | Explosion: | Fire Extinguishing Media: | Special Information: |
| Not considered to be a fire hazard. | Not considered to be an explosion hazard. | Use any means suitable for extinguishing surrounding fire. | In the event of a fire, wear full protective clothing and NIOSH-approved self-contained breathing apparatus with full facepiece operated in the pressure demand or other positive pressure mode. |
| Inhalation: | Ingestion: | Skin Contact: | Eye Contact: |
| Remove to fresh air. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Get medical attention immediately. | If swallowed, DO NOT INDUCE VOMITING. Give large quantities of water. Never give anything by mouth to an unconscious person. Get medical attention immediately. | Immediately flush skin with plenty of water for at least 15 minutes while removing contaminated clothing and shoes. Get medical attention immediately. Wash clothing before reuse. Thoroughly clean shoes before reuse. | Immediately flush eyes with plenty of water for at least 15 minutes, lifting lower and upper eyelids occasionally. Get medical attention immediately. |
Potassium silicate is a water-soluble silicate salt that is commonly used as an adhesive in welding rods.
this compound has been in use for at least a century. It is mentioned in the book handy farm devices and how to make them by Rolfe Cobleigh, associate editor American agriculturist.
