GALLIUM

n. Ga21(ga3l)'i! -u3m(u4m). A metallic element discovered in 1875 by Lecoq de Boishaudran. It is a tough, bluish-white substance of the sp. gr. of 5'9. It melts at 30 C. to form a silvery liquid which if undisturbed does not solidify, even when cooled to C. If the molten metal is brought into contact with the solid metal, it solidifies in the crystalline form. In compounds, g. acts as a trivalent radicle, forming salts analogous to those of aluminium. Symbol, Ga; atomic weight, 69'8. [B, 3.] Ammonium g.-alum. Ger., G'ammoniakalann. A crystalline substance, Ga2(SO4)3 + (NH4)2SO4 + 24H2O, soluble in water, having the composition of too; U, blue; U, lull; U4, full; U, urn; U, like u (German). [s. 135]