English Cobalt Cited by user GRALISTAIR on 15 May 2021 Cobalt is a chemical element; it has symbol Co and atomic number 27. As with nickel, cobalt is found in the Earth's crust only in a chemically combined form, save for…
English Polyester resin Cited by user GRALISTAIR on 15 May 2021 Polyester resins are synthetic resins formed by the reaction of dibasic organic acids and polyhydric alcohols.