Transition metal prevent d–d bonding, which again tends to differentiate them from the accepted transition metals. Mercury has a melting point of and is a liquid at room temperature. Transition metal In chemistry, the term transition metal (or transition element) has three possible meanings: English chemist Charles Bury (1890–1968) first used the word "transition" in this context in 1921, when he referred to a "transition series of elements" during the change of an inner layer of electrons (for example n=3 in the 4th row of the periodic table) from a stable group of 8 to one of 18, or from 18 to
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