molybdenumn.

Brit.

/məˈlɪbdənəm/, U.S.

/məˈlɪbdənəm/

Origin: A borrowing from Latin. Etymon: Latin molybdenum.

Etymology: < scientific Latin molybdenum ( S. Rinman Försök till Järnets Historia (1782) 636), alteration of molybdena molybdena n. after the names of other chemical elements (compare -ium suffix). Compare French molybdène (1782 in this sense: see molybdena n.).Molybdenum was recognized as a constituent of molybdenite by the Swedish chemist C. W. Scheele (1742–86) in 1778 and first isolated by the Swedish chemist P. J. Hjelm (1746–1813) in 1782. N.E.D. (1907) gives the pronunciation as (mǫlibdī·nɒ̆m) /mɒlɪbˈdiːnəm/.

Chemistry.

A brittle, silvery-grey chemical element, atomic no. 42, which is one of the transition metals and occurs as an essential trace element in plants and is added to steel and other alloys to give strength and corrosion resistance. Symbol Mo.

ΘΚΠ

the world > matter > chemistry > elements and compounds > metals > specific elements > molybdenum > [noun]

molybdenum1794

moly1936

1794 G. Pearson tr. L. B. Guyton de Morveau et al. Table Chem. Nomencl. (Table at end) Molybdena. Molybdenum. Regulus of Molybdena, of Hielm, in 1784.

1815 J. Smith Panorama Sci. & Art II. 408 The ore containing molybdenum has almost the appearance of plumbago.

1867 C. L. Bloxam Chemistry 393 Metallic molybdenum is obtained by reducing molybdic acid with charcoal at a white heat.

1873 H. Watts Fownes's Man. Elem. Chem. (ed. 11) 512 Molybdenum occurs in small quantity as sulphide.

1910 Encycl. Brit. I. 708/2 Vanadium, molybdenum and titanium may be expected soon to play an important part in the constitution of steel.

1955 Sci. News Let. 16 Apr. 246/1 Molybdenum, a metal coming more and more into use both alloyed with steel and compounded to form pigments and lubricants.

1986 Sunday Mail Mag. (Brisbane) 21 Dec. 16/3 Cauliflowers are very sensitive to shortage of molybdenum.

Compounds

molybdenum blue n. a complex oxide or mixture of oxides of pentavalent or hexavalent molybdenum with a strong blue colour that is produced, usually as a colloidal solution, when an acidic solution of a molybdate is reduced, and is used in chemical analysis and occasionally as a dye; (also) the colour of this substance.

ΘΚΠ

the world > matter > chemistry > elements and compounds > metals > specific elements > molybdenum > [noun] > compounds

molybdenum blue1901

1901 Jrnl. Chem. Soc. 80 ii. 163 Molybdenum blue does not appear to contain the dioxide, MoO₂,..but the semipentoxide, Mo₂O₅.

1951 Amer. Mineralogist 36 610 Ilsemannite is soluble in water, first producing a greenish blue solution which later deepens to a typical molybdenum blue.

1965 D. 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.

1996 Chem. in Brit. Sept. 20/1 The complex commonly known as molybdenum blue is a cyclic cluster of 154 molybdenum atoms with attendant ligands.

molybdenum dioxide n. a stable blue-brown oxide of molybdenum, MoO₂, which conducts electricity in the solid state.

ΚΠ

1892 H. F. Morley & M. M. P. Muir Watts' Dict. Chem. (rev. ed.) III. 431/2 Molybdenum dioxide.

1911 Encycl. Brit. XVIII. 682/1 Molybdenum dioxide, MoO₂, is formed by heating sodium trimolybdate, Na₂Mo₃O₁₀, to redness in a current of hydrogen.

1983 S. P. Parker McGraw-Hill Encycl. Chem. 631/2 Molybdenum dioxide and trioxide are the most common and most stable [oxides of molybdenum].

molybdenum disulphide n. a sulphide of molybdenum, MoS₂, which occurs naturally as molybdenite and is used as a dry lubricant.

ΚΠ

1869 H. E. Roscoe Lessons Elem. Chem. (new ed.) xxiii. 236 The chief ore of this metal is molybdenum disulphide, a mineral in appearance resembling graphite.

1959 Engineering 23 Jan. 116 Lubricating oils containing chlorine, sulphur compounds, graphite, or molybdenum disulphide, are well known as assisting parts to carry loads without scuffing.

1991 Mech. Engin. Sept. 56/3 The lubricants consist of a binder matrix..and minute particles of solid lubricating and rheological materials (such as molybdenum disulfide, graphite, or fluorocarbons) in a liquid carrier.

molybdenum oxide n. = molybdenum trioxide n.

ΚΠ

1870 N. Story-Maskelyne Catal. Coll. Minerals Brit. Mus. 14 Molybdenum Oxide..case 26.

1984 Jrnl. Microsc. 133 155 Molybdenum enrichment was detected in the anodized alloy surfaces but there was no electron diffraction evidence for a crystalline molybdenum oxide.

1989 Hydrocarbon Processing Nov. 104/1 To produce aqueous formaldehyde (AF) or urea formaldehyde precondensate (UFC) from methanol using Haldor Topsoϕe A/S FK-2 iron/molybdenum-oxide catalyst.

molybdenum sulphide n. = molybdenum disulphide n.

ΚΠ

1877 H. Watts Fownes's Man. Chem. (ed. 12) I. 484 Molybdenum..Trioxide MoO₃.—To obtain this oxide (commonly called Molybdic acid) native molybdenum sulphide is roasted, at a red heat, in an open vessel.

1976 P. Francis Volcanoes ix. 278 Around some fumaroles it is possible to find small crystals of ore minerals such as magnetite and specularite (iron oxides), molybdenite (molybdenum sulphide), [etc.].

molybdenum trioxide n. a stable oxide of molybdenum, MoO₃, which occurs naturally as molybdite, and is used esp. as a raw material in the preparation of other molybdenum compounds.

ΚΠ

1869 H. E. Roscoe Lessons Elem. Chem. (new ed.) xxiii. 236 The metal is a grey substance, which oxidises on heating in air to molybdenum trioxide, MoO₃, a yellow powder which acts as an acid, forming with bases salts called molybdates.

1983 S. P. Parker McGraw-Hill Encycl. Chem. 632/1 Molybdenum trioxide reacts with strong acids..to form complex cations, such as molybdenyl, MoO₂²⁺, and molybdyl, MoO⁴⁺.

This entry has been updated (OED Third Edition, September 2002; most recently modified version published online March 2022).

单词	molybdenum
释义	molybdenumn. Brit. /məˈlɪbdənəm/, U.S. /məˈlɪbdənəm/ Origin: A borrowing from Latin. Etymon: Latin molybdenum. Etymology: < scientific Latin molybdenum ( S. Rinman Försök till Järnets Historia (1782) 636), alteration of molybdena molybdena n. after the names of other chemical elements (compare -ium suffix). Compare French molybdène (1782 in this sense: see molybdena n.).Molybdenum was recognized as a constituent of molybdenite by the Swedish chemist C. W. Scheele (1742–86) in 1778 and first isolated by the Swedish chemist P. J. Hjelm (1746–1813) in 1782. N.E.D. (1907) gives the pronunciation as (mǫlibdī·nɒ̆m) /mɒlɪbˈdiːnəm/. Chemistry. A brittle, silvery-grey chemical element, atomic no. 42, which is one of the transition metals and occurs as an essential trace element in plants and is added to steel and other alloys to give strength and corrosion resistance. Symbol Mo. ΘΚΠ the world > matter > chemistry > elements and compounds > metals > specific elements > molybdenum > [noun] molybdenum1794 moly1936 1794 G. Pearson tr. L. B. Guyton de Morveau et al. Table Chem. Nomencl. (Table at end) Molybdena. Molybdenum. Regulus of Molybdena, of Hielm, in 1784. 1815 J. Smith Panorama Sci. & Art II. 408 The ore containing molybdenum has almost the appearance of plumbago. 1867 C. L. Bloxam Chemistry 393 Metallic molybdenum is obtained by reducing molybdic acid with charcoal at a white heat. 1873 H. Watts Fownes's Man. Elem. Chem. (ed. 11) 512 Molybdenum occurs in small quantity as sulphide. 1910 Encycl. Brit. I. 708/2 Vanadium, molybdenum and titanium may be expected soon to play an important part in the constitution of steel. 1955 Sci. News Let. 16 Apr. 246/1 Molybdenum, a metal coming more and more into use both alloyed with steel and compounded to form pigments and lubricants. 1986 Sunday Mail Mag. (Brisbane) 21 Dec. 16/3 Cauliflowers are very sensitive to shortage of molybdenum. Compounds molybdenum blue n. a complex oxide or mixture of oxides of pentavalent or hexavalent molybdenum with a strong blue colour that is produced, usually as a colloidal solution, when an acidic solution of a molybdate is reduced, and is used in chemical analysis and occasionally as a dye; (also) the colour of this substance. ΘΚΠ the world > matter > chemistry > elements and compounds > metals > specific elements > molybdenum > [noun] > compounds molybdenum blue1901 1901 Jrnl. Chem. Soc. 80 ii. 163 Molybdenum blue does not appear to contain the dioxide, MoO₂,..but the semipentoxide, Mo₂O₅. 1951 Amer. Mineralogist 36 610 Ilsemannite is soluble in water, first producing a greenish blue solution which later deepens to a typical molybdenum blue. 1965 D. 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. 1996 Chem. in Brit. Sept. 20/1 The complex commonly known as molybdenum blue is a cyclic cluster of 154 molybdenum atoms with attendant ligands. molybdenum dioxide n. a stable blue-brown oxide of molybdenum, MoO₂, which conducts electricity in the solid state. ΚΠ 1892 H. F. Morley & M. M. P. Muir Watts' Dict. Chem. (rev. ed.) III. 431/2 Molybdenum dioxide. 1911 Encycl. Brit. XVIII. 682/1 Molybdenum dioxide, MoO₂, is formed by heating sodium trimolybdate, Na₂Mo₃O₁₀, to redness in a current of hydrogen. 1983 S. P. Parker McGraw-Hill Encycl. Chem. 631/2 Molybdenum dioxide and trioxide are the most common and most stable [oxides of molybdenum]. molybdenum disulphide n. a sulphide of molybdenum, MoS₂, which occurs naturally as molybdenite and is used as a dry lubricant. ΚΠ 1869 H. E. Roscoe Lessons Elem. Chem. (new ed.) xxiii. 236 The chief ore of this metal is molybdenum disulphide, a mineral in appearance resembling graphite. 1959 Engineering 23 Jan. 116 Lubricating oils containing chlorine, sulphur compounds, graphite, or molybdenum disulphide, are well known as assisting parts to carry loads without scuffing. 1991 Mech. Engin. Sept. 56/3 The lubricants consist of a binder matrix..and minute particles of solid lubricating and rheological materials (such as molybdenum disulfide, graphite, or fluorocarbons) in a liquid carrier. molybdenum oxide n. = molybdenum trioxide n. ΚΠ 1870 N. Story-Maskelyne Catal. Coll. Minerals Brit. Mus. 14 Molybdenum Oxide..case 26. 1984 Jrnl. Microsc. 133 155 Molybdenum enrichment was detected in the anodized alloy surfaces but there was no electron diffraction evidence for a crystalline molybdenum oxide. 1989 Hydrocarbon Processing Nov. 104/1 To produce aqueous formaldehyde (AF) or urea formaldehyde precondensate (UFC) from methanol using Haldor Topsoϕe A/S FK-2 iron/molybdenum-oxide catalyst. molybdenum sulphide n. = molybdenum disulphide n. ΚΠ 1877 H. Watts Fownes's Man. Chem. (ed. 12) I. 484 Molybdenum..Trioxide MoO₃.—To obtain this oxide (commonly called Molybdic acid) native molybdenum sulphide is roasted, at a red heat, in an open vessel. 1976 P. Francis Volcanoes ix. 278 Around some fumaroles it is possible to find small crystals of ore minerals such as magnetite and specularite (iron oxides), molybdenite (molybdenum sulphide), [etc.]. molybdenum trioxide n. a stable oxide of molybdenum, MoO₃, which occurs naturally as molybdite, and is used esp. as a raw material in the preparation of other molybdenum compounds. ΚΠ 1869 H. E. Roscoe Lessons Elem. Chem. (new ed.) xxiii. 236 The metal is a grey substance, which oxidises on heating in air to molybdenum trioxide, MoO₃, a yellow powder which acts as an acid, forming with bases salts called molybdates. 1983 S. P. Parker McGraw-Hill Encycl. Chem. 632/1 Molybdenum trioxide reacts with strong acids..to form complex cations, such as molybdenyl, MoO₂²⁺, and molybdyl, MoO⁴⁺. This entry has been updated (OED Third Edition, September 2002; most recently modified version published online March 2022). < n.1794
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