Sodium silicate(Na2SiO3), commonly known as “waterglass”, is one of several chemicals that are composed of sodium, silica, and oxygen. This type products are manufactured as solids or thick liquids, depending on intended use. For instance, waterglass functions as a sealant in metal components. Lastly, although its production is a mature industry, there is ongoing research for new applications given its heat conductive properties.
A sodium silicate compound contains sodium oxide, Na2O, and silica, Si2O, or a mixture of these compounds. The chemical is a silicon-oxygen polymer containing ionic sodium (Na+) components. Such a molecular arrangement is different from typical ionic materials such as salt, which is based on formula units united by electrical attraction. By contrast, this compound is similar to carbon-based plastics since silicon-oxygen-silicon bonds between each monomer are covalent. The polymer-like nature of the matrix as well as the polar character of oxygen and sodium atoms allows for bonding of water molecules within the polymer matrix. Therefore, they often exist in hydrous allotropes. (Wells, “Structural Inorganic Chemistry”).
A method for the synthesis of this substance involves a combination of sodium carbonate (Na2CO3) and silicon dioxide (SiO2) under conditions sufficient to melt both reactants. Sodium silicate is produced by this method with sufficient efficiency to be of commercial use.
Its water solutions bind solids well, forming insulation boards that tolerate high temperatures. This property enables them to be used to as a refractory—retaining strength at high temperatures. Due to this, they can be used as linings in kilns and glass-making equipment. If water-proofed, sodium silicate(CAS number is 1344-09-8) can be used as passive fire protection, such as being incorporated into the structure for plastic pipes, to form firestop devices.
The combination of being liquid and being resistant to high heat makes these compounds useful for automobile repair. A sodium silicate solution is circulated from the radiator to seal leaks in the head gasket. This solution can also be used instead of motor oil to permanently disable a car engine prior to the auto’s destruction. Liquid sodium silicate is also useful to treat concrete to make it more water repellent.