| 释义 |
sodium Chem.|ˈsəʊdɪəm|
[f. sod-a1 + -ium. Named by Davy (1807).]
1. An elementary alkaline metal (isolated by Davy in 1807), forming the basis of soda, closely resembling potassium in its appearance and properties, and occurring most commonly in the chloride (common salt). Symbol Na (for Natrium).
1807Davy in Phil. Trans. (1808) i. 32 Potassium and Sodium are the names by which I have ventured to call the two new substances. 1812― Chem. Philos. 331, I discovered sodium a few days after I discovered potassium, in the year 1807. 1815J. Smith Panorama Sci. & Art II. 395 Sodium has a much higher point of fusion than potassium. 1856Miller Elem. Chem., Inorg. 743 Sodium has a bluish white colour; in appearance and properties it much resembles potassium, but is somewhat more volatile. 1879Proctor Pleas. Ways Sci. i. 1 A certain double dark line in the solar spectrum is due to the vapour of sodium in the sun's atmosphere.
2. attrib.
a. In the names of chemical compounds or groupings, as sodium-alcohol, sodium-amyl, sodium bicarbonate, sodium bromide, sodium carbonate, etc.; sodium Amytal Pharm., the sodium salt of Amytal, used as a sedative and hypnotic; sodium 5-ethyl-5-isopropylbarbiturate, C11H17N2O3Na; sodium Pentothal (see Pentothal).
1857Miller Elem. Chem., Org. 150 If iodide of amyl be made to act upon the sodium-alcohol. 1862Ibid. (ed. 2) 222 When sodium-ethyl is formed from zinc-ethyl by the action of sodium. Ibid. 225 Sodium-amyl would probably furnish caproate of soda. 1868Fownes' Chem. (ed. 10) 337 Sodium Chloride, when pure, is not deliquescent in moderately-dry air. Ibid., Sodium Hydrate, or Caustic Soda. Ibid. 338 Sodium Carbonates. Ibid. 345 Sodium Hyposulphite..is now used in considerable quantity for photographic purposes. 1873C. H. Ralfe Phys. Chem. 105 The potassium and sodium phosphates form three varieties of salts. 1929Proc. Soc. Exper. Biol. & Med. XXVI. 709 Anesthesia has been produced in human beings by the intravenous injection of solutions of the anhydrous sodium amytal. 1937[see Seconal]. 1938[see Amytal]. 1955A. Huxley Genius & Goddess 9 One escapes into reminiscence as one escapes into gin or sodium amytal.
b. Misc., as sodium-compound, sodium-flame, sodium vapour (freq. attrib.); sodium-amalgam, a compound of mercury and sodium; sodium-cooled a., that employs liquid sodium as a coolant; spec. of (a) an aero-engine exhaust valve, or (b) a nuclear reactor; sodium pump Physiol., a pump (pump n.1 1 e) which operates on sodium ions; sodium soap, soda soap.
1862Miller Elem. Chem., Org. (ed. 2) 219 The potassium and sodium compounds are more energetic than those of zinc. 1866W. Odling Anim. Chem. 138 Uric acid, by deoxidation with sodium-amalgam, yields a mixture of xanthine and hypoxanthine. 1871Tyndall Fragm. Sci. (1879) I. xiv. 391 We send our beam of white light through a sodium flame. 1933Discovery Feb. 50/2 In the construction of sodium vapour lamps this difficulty is overcome by introducing a rare gas into the tube. 1934Jrnl. R. Aeronaut. Soc. XXXVIII. 223 The Americans have attained and even exceeded [500 lbs. per sq. in.]..with a poppet valve (sodium cooled) engine. 1951Jrnl. Physiol. CXIV. 143 An active sodium pump cannot be ruled out on the grounds that it would require more energy than is available from the resting metabolism. 1954Sci. Amer. Dec. 38/3 A sodium-cooled reactor, which can be operated at very high temperatures, has greater thermal efficiency than a water-cooled system. 1956E. Molloy Automobile Engineer's Ref. Bk. iii. 242 In engines where exhaust-valve cooling is a serious problem, the sodium-cooled valve has been adopted. 1964[see pump n.1 1 e]. 1968M. S. Livingston Particle Physics iii. 39 A well-known example [of a multiplet] is the sodium D-line doublet which gives the yellow color to the light from a sodium-vapor lamp. 1971New Scientist 11 Mar. 529/1 Rudzinski was mainly concerned about the immense complexity of the sodium-cooled technology. 1974D. & M. Webster Compar. Vertebr. Morphol. ix. 183 Instead of osmotically equilibrating, this imbalance of cations is maintained by the cell membrane's physical characteristics plus an enzyme system, called the sodium pump, which actively removes sodium from inside the cell. 1977Time 15 Aug. 11/3 What worries them in particular is that Super Phénix will produce energy from a sophisticated sodium-cooled reactor eight times more powerful than smaller, water-cooled plants.
c. Used attrib. and in Comb. with reference to (the intense yellow light emitted from) discharge tubes containing sodium vapour, used esp. for street lighting.
1888Rutley Rock-forming Min. 128 The refractive index of quartz..in sodium-light. 1912Jrnl. Soc. Chem. Industry 31 Oct. 1010/2 (heading) Polarisation; Sodium lamps for. 1933Discovery Oct. 318/2 The electrical impulses corresponding to the television picture signals are converted into the light variations of a specially designed sodium tube. 1956R. Fuller Image of Society viii. 195 The sodium lamps of the bypass. 1959New Statesman 8 Aug. 152/2 Their fight is often associated with the campaign against concrete lamp-posts, sodium lighting and similar ‘outrages’ on our towns and cities. 1967A. J. Marshall in L. Deighton London Dossier 138 Walking in the sodium-lit Kilburn High Road. 1973J. Mann Only Security x. 132 Thea pressed the whole row of light switches and..the sodium strips flickered into brilliance. 1977D. Harsent Dreams of Dead 35 Midnight, bruised insomniacs, alive to the growing silence and opening to the sodium glare like flowers.
d. Objective, as sodium-demanding, sodium-retaining adjs.
1977J. L. Harper Population Biol. Plants xxi. 655 The life cycle strategy is likely in such a case to be influenced by the optimal allocation of sodium between parents and offspring and between the various sodium-demanding activities. 1977Proc. R. Soc. Med. LXX. 692/1 One of the hypotheses..has been that these patients fail to escape normally from the sodium-retaining effect of aldosterone.
▸ sodium nitroprusside n. Chem. the compound Na2[Fe(CN)5NO], which forms a deep-red crystalline dihydrate and is used as an analytical reagent and as an antihypertensive.
1849L. Playfair in Philos. Trans. (Royal Soc.) 139508 It would appear that the barium and *sodium nitroprusside contained a body in which the iron and cyanogen are in the same proportion as in ferrocyanogen. 1906H. J. H. Fenton Notes Qualitative Anal. (new ed.) 27 Sodium nitroprusside, Na2[Fe(CN)5NO], gives a fine purple coloration, probably due to a double salt. 2003European Jrnl. Anaesthesiol. 20 697 We set out to compare the efficacy of clevidipine and sodium nitroprusside infusions in the control of blood pressure and the haemodynamic changes they produce in hypertensive patients. |