Scandium(iii) triflate-promoted serine/threonine-selective peptide bond cleavage.

See more Scandium products. Scandium (atomic symbol: Sc, atomic number: 21) is a Block D, Group 3, Period 4 element with an atomic weight of 44.955912. The number of electrons in each of Scandium's shells is [2, 8, 9, 2] and its electron configuration is [Ar] 3d¹ 4s². The scandium atom has a radius of 162 pm and a Van der Waals radius of 216 pm.Scandium was predicted by Dmitri Mendeleev in 1871 and actually discovered and isolated by Lars Nilson in 1879. One of the transition metals, scandium has a silvery-white appearance in its elemental form which oxidizes to yellow or pinkish upon contact with air. It is occasionally included in the classification of the rare earth elements. Scandium is found in concentrated amounts in the minerals euxenite, gadolinite and thortveitite however, due to the difficulties in the preparation of metallic scandium, global trade of the pure metal is very limited. The origin of the name scandium comes from the Latin word 'scandia' meaning Scandinavia.

Fluorine is a Block P, Group 17, Period 2 element. Its electron configuration is [He]2s²2p⁵. The fluorine atom has a covalent radius of 64 pm and its Van der Waals radius is 135 pm. In its elemental form, CAS 7782-41-4, fluorine gas has a pale yellow appearance. Fluorine was discovered by André-Marie Ampère in 1810. It was first isolated by Henri Moissan in 1886.

See more Sulfur products. Sulfur (or Sulphur) (atomic symbol: S, atomic number: 16) is a Block P, Group 16, Period 3 element with an atomic radius of 32.066. The number of electrons in each of Sulfur's shells is 2, 8, 6 and its electron configuration is [Ne] 3s² 3p⁴. In its elemental form, sulfur has a light yellow appearance. The sulfur atom has a covalent radius of 105 pm and a Van der Waals radius of 180 pm. In nature, sulfur can be found in hot springs, meteorites, volcanoes, and as galena, gypsum, and epsom salts. Sulfur has been known since ancient times but was not accepted as an element until 1777, when Antoine Lavoisier helped to convince the scientific community that it was an element and not a compound.