From The School of Biomedical Sciences Wikiperiodic table and has an atomic number of 16 and a standard relative atomic mass of 32.065. The name may have been derived from the Arabic ‘sufra’ meaning yellow, or the Sanskrit ‘shulbari’ meaning enemy (ari) of copper (shulba). It is a naturally occuring element which is frequently found and regarded as an essential element for life. It is found in the amino acids methionine and cysteine. In cysteine the - SH group reacts with another -SH group on a different cysteine forming a disulphide bond 
- ↑ NIST. Sulfur. 2016 [cited 03/12/16]; Available from: http://webbook.nist.gov/cgi/cbook.cgi?ID=C7704349&amp;amp;amp;Mask=40
- ↑ G. Eggert, M. Weichert, H. Euler, B. Barbier, Some news about Black Spots., 2004, Proceedings of Metal, p142 (pdf download).
- ↑ Berg J.,Tymoczko J. and Stryer L. (2012) Biochemistry. 7th edition, Basinstoke: Freeman.