Liquid the distances between the molecules become smaller. When the liquid reaches its freezing point the molecules will usually lock into a very specific order, called crystallizing, and the bonds between them become more rigid, changing the liquid into its solid state (unless supercooling occurs). Only two elements are liquid at standard conditions for temperature and pressure: mercury and bromine. Four more elements have melting points slightly above room temperature: francium, caesium, gallium and rubidium. Metal alloys that are liquid at room temperature include NaK, a sodium-potassium metal alloy, galinstan, a fusible alloy liquid, and some amalgams (alloys involving mercury). Pure
Liquid crystal Rod-shaped molecules have an elongated, anisotropic geometry which allows for preferential alignment along one spatial direction. • The molecular shape should be relatively thin, flat or bowl-like, especially within rigid molecular frameworks. • The molecular length should be at least 1.3 nm, consistent with the presence of long alkyl group on many room-temperature liquid crystals. • The structure should not be branched or angular, except for the bowlics. • A low melting point is preferable in order to avoid metastable, monotropic liquid crystalline phases. Low-temperature mesomorphic behavior in general is technologically more useful, and alkyl terminal groups promote this. An