Solid Amorphous Bi, Fe, and Ga as Examples of Liquid-Like Amorphous Substances

Abstract

Solid amorphous Bi, Fe, and Ga are liquid-like, i.e., they have the same structure as the respective melt. However, the degree of order is higher than in the liquid state. A detailed analysis of the structure of liquid-like solid amorphous Bi and Fe (8-coordination) is given. Their atomic distribution curves are compared with those of molten Bi and Na (8-coordination). By discussion of the electron diffraction patterns of solid amorphous and of molten Bi one finds a layer lattice structure (IInd structure) which is derived from the appertaining lattice. The Fourier analysis of the intensity curves, however, demands the spherical close packing in the form of a straight atomic chain (Ist structure). Fujime’s electron diffraction patterns of solid amorphous Fe also show that there exist two structures simultaneously: a layer lattice structure of the appertaining lattice (IInd structure) and the spherical close packing, this time as a plane zigzag chain (Ist structure) as in molten Na. This double structure is also obtained in solid amorphous and in molten Ga. The noncrystalline Ga has an especially simple structure as found immediately by discussion of the intensity curve. In solid amorphous and in molten Bi, Fe, and Ga the simultaneous occurrence of two structures stabilizes the noncrystalline state.