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Solid hydrogen is the solid state of the element hydrogen, achieved by decreasing the temperature below hydrogen's melting point of 14.01 K (−259.14 °C; −434.45 °F). It was collected for the first time by James Dewar in 1899 and published with the title "Sur la solidification de l'hydrogène" (English: On the freezing of hydrogen) in the ...
Liquid hydrogen ( H2(l)) is the liquid state of the element hydrogen. Hydrogen is found naturally in the molecular H 2 form. [ 4] To exist as a liquid, H 2 must be cooled below its critical point of 33 K. However, for it to be in a fully liquid state at atmospheric pressure, H 2 needs to be cooled to 20.28 K (−252.87 °C; −423.17 °F). [ 5]
The Gmelin rare earths handbook lists 1522 °C and 1550 °C as two melting points given in the literature, the most recent reference [ Handbook on the chemistry and physics of rare earths, vol.12 (1989)] is given with 1529 °C. The World Book encyclopedia from 2002 lists 1529 °C. 89 Ac actinium (Ac-227 ?)
In aqueous solutions, hydrogen peroxide forms a eutectic mixture, exhibiting freezing-point depression down as low as -56 °C; pure water has a freezing point of 0 °C and pure hydrogen peroxide of -0.43 °C. The boiling point of the same mixtures is also depressed in relation with the mean of both boiling points (125.1 °C).
Hydrogen is a chemical element; it has symbol H and atomic number 1. It is the lightest element and, at standard conditions, is a gas of diatomic molecules with the formula H2, sometimes called dihydrogen, [ 11] but more commonly called hydrogen gas, molecular hydrogen or simply hydrogen. It is colorless, odorless, tasteless, [ 12] non-toxic ...
Heavy water ( deuterium oxide, 2. H. 2O, D. 2O) is a form of water whose hydrogen atoms are all deuterium ( 2. H or D, also known as heavy hydrogen) rather than the common hydrogen-1 isotope ( 1. H, also called protium) that makes up most of the hydrogen in normal water. [ 3]
Melting point. The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state from solid to liquid. At the melting point the solid and liquid phase exist in equilibrium. The melting point of a substance depends on pressure and is usually specified at a standard pressure such as 1 atmosphere or 100 ...
Hydrogen safety. The Hindenburg disaster is an example of a large hydrogen explosion. Hydrogen safety covers the safe production, handling and use of hydrogen, particularly hydrogen gas fuel and liquid hydrogen. Hydrogen possesses the NFPA 704 's highest rating of four on the flammability scale because it is flammable when mixed even in small ...