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A substance is pyrophoric (from Ancient Greek: πυροφόρος, pyrophoros, 'fire-bearing') if it ignites spontaneously in air at or below 54 °C (129 °F) (for gases) or within 5 minutes after coming into contact with air (for liquids and solids). [1] Examples are organolithium compounds and triethylborane.
Water-reactive substances [1] are those that spontaneously undergo a chemical reaction with water, often noted as generating flammable gas. [2] Some are highly reducing in nature. [ 3 ] Notable examples include alkali metals , lithium through caesium , and alkaline earth metals , magnesium through barium .
A pyrotechnic composition is a substance or mixture of substances designed to produce an effect by heat, light, sound, gas/smoke or a combination of these, as a result of non-detonative self-sustaining exothermic chemical reactions. Pyrotechnic substances do not rely on oxygen from external sources to sustain the reaction.
Iron is by far the most reactive element in its group; it is pyrophoric when finely divided and dissolves easily in dilute acids, giving Fe 2+. However, it does not react with concentrated nitric acid and other oxidizing acids due to the formation of an impervious oxide layer, which can nevertheless react with hydrochloric acid. [10]
A steel bottle containing MgCp 2 (magnesium bis-cyclopentadienyl), which, like several other organometallic compounds, is pyrophoric in air.. Organometallic compounds are distinguished by the prefix "organo-" (e.g., organopalladium compounds), and include all compounds which contain a bond between a metal atom and a carbon atom of an organyl group. [2]
tert-butyllithium is a pyrophoric substance, meaning that it spontaneously ignites on exposure to air. Air-free techniques are important so as to prevent this compound from reacting violently with oxygen and moisture: t-BuLi + O 2 → t-BuOOLi t-BuLi + H 2 O → t-BuH + LiOH. The solvents used in common commercial preparations are themselves ...
Despite its highly pyrophoric nature, diethylzinc is an important chemical reagent. It is used in organic synthesis as a source of the ethyl carbanion in addition reactions to carbonyl groups. For example, the asymmetric addition of an ethyl group to benzaldehyde [ 8 ] and imines . [ 9 ]
As a pyrophoric substance, diborane reacts exothermically with oxygen to form boron trioxide and water: 2 B 2 H 6 + 6 O 2 → 2 B 2 O 3 + 6 H 2 O (ΔH r = −2035 kJ/mol = −73.47 kJ/g) Diborane reacts violently with water to form hydrogen and boric acid: B 2 H 6 + 6 H 2 O → 2 B(OH) 3 + 6 H 2 (ΔH r = −466 kJ/mol = −16.82 kJ/g) Diborane ...