Period 5 element in South Africa, the Stillwater Complex in Montana, United States, the Thunder Bay District of Ontario, Canada, and the Norilsk Complex in Russia. Recycling is also a source of palladium, mostly from scrapped catalytic converters. The numerous applications and limited supply sources of palladium result in the metal attracting considerable investment interest. Silver is a metallic chemical element with the chemical symbol Ag (, from the Indo-European root "*arg-" for "grey" or "shining") and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal.
Thermal conductivity is reduced, with this behaviour governed by the Knudsen number, defined as formula_27, where formula_28 is the mean free path of gas molecules and formula_29 is the typical gap size of the space filled by the gas. In a granular material formula_29 corresponds to the characteristic size of the gaseous phase in the pores or intergranular spaces. Isotopically pure diamond can have a significantly higher thermal conductivity, increasing from 2,200 W·m·K (for pure natural diamond, 98.9% C) to 3,320 (for 99.9% enriched), possibly 41,000; with 200,000 "predicted" for 99.999% C.) At the atomic level, there are no simple, correct expressions