Silicon. Silicon-28 . Silicon 28 . A trace element that constitutes about 27.6% of the earth's crust in the form of SILICON DIOXIDE. It does not occur free in nature. Silicon has the atomic symbol Si, atomic number 14, and atomic weight [28.084; 28.086]. . 0.68
Silicones. Silicone . A broad family of synthetic organosiloxane polymers containing a repeating silicon-oxygen backbone with organic side groups attached via carbon-silicon bonds. Depending on their structure, they are classified as liquids, gels, and elastomers. (From Merck Index, 12th ed) . 0.65
Silicosis. Silicoses . A form of pneumoconiosis resulting from inhalation of dust containing crystalline form of SILICON DIOXIDE, usually in the form of quartz. Amorphous silica is relatively nontoxic. . 0.57
Sulfur Dioxide. Sulfurous Anhydride . Anhydride, Sulfurous . Dioxide, Sulfur . A highly toxic, colorless, nonflammable gas. It is used as a pharmaceutical aid and antioxidant. It is also an environmental air pollutant. . 0.56
Dioxins. A family of compounds that contain the 1,4-dioxin structure. Many specific dioxin derivatives are listed as CARCINOGENS; TERATOGENS; or MUTAGENS. . 0.56
