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Alanine was first synthesized in 1850 when Adolph Strecker combined acetaldehyde and ammonia with hydrogen cyanide. [8] [9] [10] The amino acid was named Alanin in German, in reference to aldehyde, with the interfix-an-for ease of pronunciation, [11] the German ending -in used in chemical compounds being analogous to English -ine.
Though often placed at the top of the alkali metal column in the periodic table, hydrogen does not, under ordinary conditions, exhibit the properties of an alkali metal. Instead, it forms diatomic H 2 molecules, similar to halogens and some nonmetals in the second period of the periodic table, such as nitrogen and oxygen .
[63] [64] Boyle did not note that the gas was inflammable, but hydrogen would play a key role in overturning the phlogiston theory of combustion. [65] In 1766, Henry Cavendish was the first to recognize hydrogen gas as a discrete substance, by naming the gas from a metal-acid reaction "inflammable air".
Gas properties. Hazard properties: MSDS. N/A. Main hazards: ... Pharmacological properties ... ^a EINECS for L-alanine ^a CID 602 from PubChem ^a CID 5950 from PubChem
Hydrogen in an electrical discharge tube. Hydrogen is a colourless, odourless, and comparatively unreactive diatomic gas with a density of 8.988 × 10 −5 g/cm 3 and is about 14 times lighter than air. It condenses to a colourless liquid −252.879 °C and freezes into an ice- or snow-like solid at −259.16 °C.
The metal reacts with the water first, breaking the hydrogen bonds in the water and producing hydrogen gas; this takes place faster for the more reactive heavier alkali metals. Second, the heat generated by the first part of the reaction often ignites the hydrogen gas, causing it to burn explosively into the surrounding air.
Various metals, together with oxygen, can form very complex and thermally stable structures rivaling those of organic compounds; [citation needed] the heteropoly acids are one such family. Some metal oxides are also similar to carbon in their ability to form both nanotube structures and diamond-like crystals (such as cubic zirconia).
The 1:1 complex is tetrahedral in the gas phase, [26] but in the solid phase it is dimeric with bridging hydrogen centres, [(CH 3) 3 NAlH 2 (μ-H)] 2. [27] The 1:2 complex adopts a trigonal bipyramidal structure. [26] Some adducts (e.g. dimethylethylamine alane, (CH 3 CH 2)(CH 3) 2 N·AlH 3) thermally decompose to give aluminium and may have ...