Fr.: nombre d'oxydation
The total number of electrons that an atom either gains or loses in order to form a chemical bond with another atom. In other words, the charge that atom would have if the compound was composed of ions. The oxidation number of an atom is zero in a neutral substance that contains atoms of only one element. Same as → oxidation state.
Fr.: état d'oxydation
Same as → oxidation number.
Past participle of → oxidize.
Agent noun from → oxidize.
A gaseous → chemical element; symbol O. Oxygen is the most abundant element in the → Universe not produced in the → Big Bang, and the third most common overall. It is a colorless, tasteless, odorless gas that is the second most abundant constituent of dry air (20.95% by volume). → Atomic number 8; → atomic weight 15.9994; → melting point -218.4°C; → boiling point -182.962°C; → density 1.429 grams per liter at STP. Oxygen was discovered for the first time by a Swedish Chemist, Carl Wilhelm Scheele, in 1772. Joseph Priestley, an English chemist, independently, discovered oxygen in 1774 and published his findings the same year, three years before Scheele published. Antoine Lavoisier, a French chemist, also discovered oxygen in 1775, was the first to recognize it as an element.
From Fr. oxygène, literally "acid former," coined in 1777 by the Fr. chemist Antoine-Laurent Lavoisier (1743-1794), from Gk. oxys "sharp, acid" + Fr. -gène "something that produces" from Gk. -genes "formation, creation" (cognate with Pers. zâdan "to bring forth, give birth;" Mid.Pers. zâtan; Av. zan- "to bear, give birth to a child, be born," infinitive zazāite, zāta- "born;" cf. Skt. janati "begets, bears;" L. gignere "to beget," nasci "to be born," as above, PIE base *gen- "to give birth, beget").
Oksižen, loan from Fr., as above.
Fr.: combustion de l'oxygène
A form of oxygen, O3, in which the molecule is made of three atoms instead of the usual two.
From Ger. Ozon, coined in 1840 by Ger. chemist Christian Friedrich Schönbein (1799-1868) from Gk. ozon, neute pr.p. of ozein "to smell." So called for its peculiar odor.
surâx-e ozon (#)
Fr.: trou d'ozone
Not really a "hole," but a region of exceptionally depleted ozone in the stratosphere over the Antarctic that happens at the beginning of Southern Hemisphere spring (August-October). It was first noticed in the 1970s by a research group from the British Antarctic Survey.
lâye-ye ozon (#)
Fr.: couche d'ozone
An atmospheric layer that contains a high proportion of oxygen that exists as ozone. It acts as a filtering mechanism against incoming ultraviolet radiation. It is located between the troposphere and the stratosphere, around 15 to 20 kilometers above the Earth's surface.
separ-e ozon (#)
Fr.: bouclier d'ozone
The ozone layer within the stratosphere that filters out potentially lethal intensities of ultraviolet radiation from the Sun.
→ ozone; shield, from O.E. scield, scild, related to sciell "seashell, eggshell," from P.Gmc. *skeldus (cf. Du. schild, Ger. Schild, Goth. skildus); PIE base *(s)kel- "to cut."
Separ "shield," from Mid.Pers. spar "shield;" cf. Skt. phalaka- "board, lath, leaf, shield," phálati "(he) splits;" Gk. aspalon "skin, hide," spolas "flayed skin," sphalassein "to cleave, to disrupt;" O.H.G. spaltan "to split;" Goth. spilda "board;" PIE base *(s)p(h)el- "to split, to break off;" → ozone.