Silver/Scandium-Cocatalyzed Bicyclization of ?-Alkynyl Ketones Leading to Benzo[c]xanthenes and Naphtho[1,2-b]benzofurans.

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.

See more Silver products. Silver (atomic symbol: Ag, atomic number: 47) is a Block D, Group 11, Period 5 element with an atomic weight of 107.8682. The number of electrons in each of Silver's shells is 2, 8, 18, 18, 1 and its electron configuration is [Kr]4d¹⁰ 5s¹. The silver atom has a radius of 144 pm and a Van der Waals radius of 203 pm. Silver was first discovered by Early Man prior to 5000 BC. In its elemental form, silver has a brilliant white metallic luster. It is a little harder than gold and is very ductile and malleable, being exceeded only by gold and perhaps palladium. Pure silver has the highest electrical and thermal conductivity of all metals and possesses the lowest contact resistance. It is stable in pure air and water, but tarnishes when exposed to ozone, hydrogen sulfide, or air containing sulfur. It is found in copper, copper-nickel, lead, and lead-zinc ores, among others. Silver was named after the Anglo-Saxon word "seolfor" or "siolfur," meaning 'silver'.