Before revision: The IUPAC adopted the spelling sulfur in 1990 or 1971, depending on the source cited, as did the Nomenclature Committee of the Royal Society of Chemistry in 1992, restoring the spelling sulfur to Britain.
After revision: The IUPAC adopted the spelling sulfur in 1990 as did the Nomenclature Committee of the Royal Society of Chemistry in 1992, restoring the spelling sulfur to Britain.