sulph

Sulph, the traditional British spelling of sulfur, denotes the chemical element with symbol S and atomic number 16. It is a nonmetal that occurs widely in the Earth's crust and in biological systems, both as elemental sulfur and in a variety of sulfur-containing compounds.

Elemental sulph is a bright yellow, crystalline solid at room temperature. It is relatively brittle, a poor conductor of electricity, and exists in several allotropes, notably rhombic and monoclinic forms that are stable at different temperatures.

In nature, sulph is found near volcanic vents and hot springs, and in minerals such as sulfide ores (for example pyrite) and sulfate minerals (like gypsum). Industrially, most sulph is obtained from sulfur-containing ores and as a byproduct of refining fossil fuels; the element is central to the production of sulfuric acid via the Contact Process.

Chemically, sulph forms compounds in multiple oxidation states, from -2 in sulfides (S2−) to +6 in sulfates (SO4^2−). The most important compound is sulfuric acid (H2SO4), used in fertilizers, chemical manufacturing, and petroleum processing. Elemental sulph can burn in air to yield sulfur dioxide (SO2).

Biologically, sulfur is essential for all living organisms. It is a component of the amino acids cysteine and methionine and of several vitamins and cofactors. It also plays a key role in the global sulfur cycle, moving among minerals, soils, atmosphere, and biomass.

Safety: sulfur compounds can be irritants or toxic in certain forms. Sulfur dioxide released by burning sulfur is a respiratory hazard; proper handling and ventilation are important in industrial settings.