Glass-to-metal seal absorb the stresses from thermal expansion mismatches. Due to its very low vapor pressure, indium finds use in glass-metal seals used in vacuum technology. Gallium is a soft metal with melting point at 30 °C. It readily wets glasses and most metals and can be used for seals that can be assembled/disassembled by just slight heating. It can be used as a liquid seal up to high temperatures or even at lower temperatures when alloyed with other metals (e.g. as galinstan). Mercury is a metal liquid at normal temperature. It was used as the earliest glass-to-metal seal and is still
Chlorine perchlorate Chlorine perchlorate Chlorine perchlorate is the chemical compound with the formula ClO. This chlorine oxide is an asymmetric oxide, with one chlorine atom in oxidation state +1 and the other +7, with proper formula ClOClO. It is produced by the photolysis of chlorine dioxide at room temperature with 436 nm ultraviolet light: Chlorine perchlorate can also be made the following reactions at −45 °C. Chlorine perchlorate is a pale greenish liquid which decomposes at room temperature. It is less stable than ClO and decomposes to O, Cl and ClO at room temperature. Chlorine perchlorate reacts with metal chlorides forming anhydrous