Argon A chemical element, Ar, atomic number 18, and atomic weight 39.948. Argon is the third member of group 18 in the periodic table. The gaseous elements in this group are called the noble, inert, or rare gases, although argon is not actually rare. The Earth’s atmosphere is the only natural argon source; however, traces

Ammine One of a group of complex compounds formed by the coordination of ammonia molecules with metal ions and, in a few instances, such as calcium, strontium, and barium, with metal atoms. Although ammines are formally analogous to many salt hydrates, the general characteristics of the group of ammines differ considerably from those of the

Organic compounds possessing one or more basic amino groups and one or more acidic carboxyl groups. Of the more than 80 amino acids which have been found in living organisms, about 20 serve as the building blocks for the proteins. All the amino acids of proteins, and most of the others which occur naturally, are