Lewis acids and bases studied chemical bonding. In 1923, Lewis wrote "An acid substance is one which can employ an electron lone pair from another molecule in completing the stable group of one of its own atoms." The Brønsted–Lowry acid–base theory was published in the same year. The two theories are distinct but complementary. A Lewis base is also a Brønsted–Lowry base, but a Lewis acid doesn't need to be a Brønsted–Lowry acid. The classification into hard and soft acids and bases (HSAB theory) followed in 1963. The strength of Lewis acid-base interactions, as measured by the standard enthalpy of formation of an adduct
Blossom, Bubbles and Buttercup mysterious substance called "Chemical X" into the mixture, creating, instead of the "perfect little girl", three girls (each possessing one of the above elements dominating her personality), and granting all three superpowers including flight, superhuman strength, super speed, near invulnerability, x-ray vision, super senses, heat vision, energy projection, invisibility, and control over lightning. In the original pilot, the accidental substance was a can of "Whoopass", which was replaced by "Chemical X" in the aired version. The three girls all have oval-shaped heads, abnormally large eyes (inspired by Margaret Keane's art), stubby arms and legs, and lack noses, ears, fingers, necks,