Chromium metal is an essential trace element, but hexavalent chromium Cr (VI) is very toxic and carcinogenic. Chromium is a silver, lustrous, very hard metal that can take a high mirror polish. It is also odorless, tasteless, and malleable. The metal forms a thin protective oxide coating in air.
Sep 09, 2020 · The ratio of the rate of heat flow per unit area to the negative of the temperature gradient is called the thermal conductivity of the material: () d Q d t = − K A d T d x. I am using the symbol K for thermal conductivity. Other symbols often seen are k or λ. Its SI unit is W m −1 K −1.