Sulfur is a yellow mineral known from antiquity. It is also a necessary nutrient for plants. Its other name, brimstone, and its association with the Christian hell probably come from sulfur being found around volcanoes.
Although elemental sulfur is not toxic, its various gases are. These include sulfur dioxide from burning and hydrogen sulfide, the distinctive odor of rotten eggs. The poet Homer writes of sulfur used for fumigation, and early doctors used it to treat infections and parasites.
Sulfur was notable in medieval alchemy, representing life. Sulfur would be critical to creating the philosopher's stone that granted immortality. Its yellow color suggested gold, and so sulfur might be a key ingredient in the transformation of other substances to the yellow metal.
In the 18th century, the basic concept of chemical elements was being sorted out. French chemist Antoine Lavoisier promoted the idea that sulfur was an element. Meanwhile, the expanding Industrial Revolution found uses for sulfur, especially in the form of sulfuric acid.
Sulfur was once mined and, in fact, simply picked off the ground. It is forced up from the Earth's interior at geologic vents, hot springs, and volcanoes. Sulfur can also be found under salt domes. The volcanic island of Sicily supplied sulfur to much of Europe from underground mines that were worked in horrible conditions.
Mining, however, is no longer a significant source of sulfur. Sulfur is found and unwanted in petroleum and natural gas. Extracted as hydrogen sulfide, it can be sold as sulfuric acid or as other substances. Most commercial sulfur products now come from purifying fossil fuels.
Properties and Uses
Sulfur is a reactive yellow solid found under oxygen in the period table and sharing some of the same behavior. Sulfur is most familiar as a yellow powder or soft stone, but it has several other forms (much like carbon). The hard amorphous "plastic sulfur" is familiar to chemistry students.
Sulfur forms many compounds, and so its uses in industry are immense. Sulfuric acid is the most fundamental of industrial acids. It has been used since ancient times to transform one substance into another. For example, sulfuric acid is used in turning phosphate rocks into phosphate fertilizer.
In agriculture, sulfur is a major plant nutrient. It is supplied in fertilizer in the form of low-concentration sulfates (calcium sulfate, gypsum) or the simple element.