| 释义 |
molybdenum Chem.|məˈlɪbdənəm, mɒlɪbˈdiːnəm|
[mod.L., alteration of molybdena.]
a. A metallic element (symbol Mo) occurring in combination, as in molybdenite, wulfenite, etc.
When separated it is a brittle, almost infusible silver-white metal, permanent at ordinary temperatures, but rapidly oxidized by heat. molybdenum oxide = molybdite (Cassell 1885). molybdenum sulphide = molybdenite (Ibid.).
1816J. Smith Panorama Sci. & Art II. 408 The ore containing molybdenum has almost the appearance of plumbago. 1873Watts Fownes' Chem. (ed. 11) 512 Molybdenum occurs in small quantity as sulphide.
b. molybdenum blue, a complex oxide or mixture of oxides of pentavalent or hexavalent molybdenum with a strong blue colour that is produced, usu. as a colloidal solution, when an acidic solution of a molybdate is reduced, and is used in chemical analysis and occas. as a dye; also, the colour of this substance.
1901Jrnl. Chem. Soc. LXXX. ii. 163 Molybdenum blue does not appear to contain the dioxide, MoO2,..but the semipentoxide, Mo2O5. 1920F. A. Mason tr. G. von Georgievics's Text-bk. Dye Chem. 542 Molybdenum blue..was used experimentally for a certain time on silk and cotton materials. 1951Amer. Mineralogist XXXVI. 610 Ilsemannite is soluble in water, first producing a greenish blue solution which later deepens to a typical molybdenum blue. 1952Kirk & Othmer Encycl. Chem. Technol. IX. 203 The present importance of molybdenum blue rests on the fact that several colorimetric methods depend upon it: (1) the determination of trace quantities of phosphorus or phosphates by the preferential reduction of phosphomolybdic acid; and (2) a number of other methods employing phosphomolybdic acid as a reagent (for phenols, tyrosine, tryptophan, etc.) for reducing compounds. 1965D. Abbott Inorg. Chem. xii. 642 Molybdenum ‘blue’ is an oxide formed when an acidified molybdate solution is greatly reduced. It has variable composition, usually about 67–68 per cent Mo. |