Ag@Fe3O4 Core-Shell Surface-Enhanced Raman Scattering Probe for Trace Arsenate Detection.

See more Iron products. Iron (atomic symbol: Fe, atomic number: 26) is a Block D, Group 8, Period 4 element with an atomic weight of 55.845. The number of electrons in each of Iron's shells is 2, 8, 14, 2 and its electron configuration is [Ar] 3d⁶ 4s². The iron atom has a radius of 126 pm and a Van der Waals radius of 194 pm. Iron was discovered by humans before 5000 BC. In its elemental form, iron has a lustrous grayish metallic appearance. Iron is the fourth most common element in the Earth's crust and the most common element by mass forming the earth as a whole. Iron is rarely found as a free element, since it tends to oxidize easily; it is usually found in minerals such as magnetite, hematite, goethite, limonite, or siderite. Though pure iron is typically soft, the addition of carbon creates the alloy known as steel, which is significantly stronger.

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'.