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Molybdenum characteristics

What is molybdenum?

1High melting point

High melting point

Molybdenum has the fifth highest melting point among metals. It has a low thermal expansion coefficient and extremely high shape stability even under high temperature environments.

2Large electric resistance

Large electric resistance

Molybdenum has relatively large electric resistance. We offer it as a heater for high-temperature furnaces and electrodes for lighting.

3Easy workability

Easy workability

Molybdenum, which has relatively easy workability among high melting point metals, can be applied for complex shapes such as boxes and meshes.

Hard, silver white molybdenum, named from the ore molybdenite by K. W. Schale of Sweden, is one of the rare metals.

Molybdenum is often used as an additive for steel materials. Using its characteristics – high melting point, excellent mechanical features, relatively easy workability compared to tungsten, etc. – it is an Indispensable metal in various applications: ribbon and wire in the field of lighting; and semiconductor substrates, glass melting electrodes, heaters and reflectors in high-temperature furnaces, and sputtering targets as wiring materials for solar cells and flat panels in the field of power electronics.

Molybdenum physical properties
Atomic number 42
Density
(Mg/cm3
293K 10.28
Melting point(K) 2,890
Boiling point(K) 4,885
Vapor pressure
(Pa)
2000K 3・10-5
Resistivity
(10-8Ωm)
300K 5.2
Specific heat
(J/kg・K)
273K~373K 259
Thermal conductivity(W/m・K) 300K 138
Linear expansion coefficient
(10-6/K)
293
293~2000K
4.8
6.7
Work function
(eV)
Single crystal
Polycrystal
 
4.6
Thermal neutron capture cross section area
(10-28m2
300K 2.60

Chemical properties

  • In the air, oxidation starts at room temperature, proceeding considerably in the dark red temperature.
  • Molybdenum does not react at room temperature with dried oxygen, but it rapidly oxidizes at 500℃ or higher, and it evaporates at 650℃ or higher turning into MoO3 of white mouse color.
  • It reacts with sulfur, carbon or silicon easily at high temperature to produce MoS₂, Mo₂C, MoSi₂, etc.
  • Nitrogen gradually dissolves into molybdenum from 600℃ and reacts extremely at 1,200℃, producing a fragile compound. Nitride is produced at 1,500℃ or higher.
  • The affinity for arsenic is strong.
  • It corrodes little in hydrofluoric acid, hydrochloric acid and sulfuric acid at 20 ℃, but corrodes significantly in nitrate, high concentration sulfate (250 ℃) and aqua regia.
Molybdenum: Reaction with gases
Substance Temperature Reaction
Air 200℃ Oxidizes a little
≧400℃ Produces MoO3
Oxygen 200℃ Oxidizes a little
≧400℃ Produces MoO3
Vapor ≧700℃ Oxidizes
Nitrogen ≧1,500℃ Produces nitrides
Carbon monoxide ≧1,400℃ Produces carbides
Carbon dioxide 1,200℃ Oxidizes
Hydrocarbon 1,100℃ Carbonizes
Chlorine 250℃ Produces chloride
Bromine 250℃ Produces bromide
Iodine 800℃ No reaction
Hydrogen

All temperature

No reaction
Hydrogen sulfide 1,200℃ Produces MoS2
Sulfur dioxide 600℃

Produces MoO2

Nitrous oxide
Nitric oxide

600℃ Produces MoO3
Ammonia   No reaction
Molybdenum : Reaction with solids
Substance Temperature Reaction
Carbon ≧1,100℃ Carbonizes
Magnesia 1,600℃ Reaction
Zirconia 2,200℃ Reaction
Thoria 1,900℃ Reaction
Alumina 1,900℃ No reaction
Sulfur 600℃ Corrodes
Tungsten 2,000℃ Reaction
Beryllia up to 1,900℃ Reaction
Molybdenum: Reaction with molten metals
Substance Temperature Reaction
Aluminum 600℃ Stable
Beryllium   Not stable
Lead up to  1,200℃ Stable
Lead (with oxygen) up to about 500℃ Stable
≧500℃ Not stable
Cesium up to 870℃ Stable
≧870℃ Not stable
Iron   Not stable
Gallium up to 400℃ Stable
Gold   Stable
Potassium up to 1,200℃ Stable
Cobalt   Not stable
Copper up to 1,300℃ Stable
Lithium up to 1,400℃ Stable
Magnesium up to 1,000℃ Stable
Sodium up to 1,030℃ Stable
Sodium (0.5% oxygen) up to 400℃ Stable
≧400℃ Not stable
Nickel   Not stable
Plutonium   Stable
Mercury up to 600℃ Stable
≧600℃ Not stable
Rubidium up to 1,000℃ Stable
Scandium   Not stable
Rare metal up to 1,100℃ Stable
≧1,400℃ Not stable
Silver   Stable
Thallium   Not stable
Uranium   Not stable
Bismuth up to 1,400℃ Stable
Zinc up to 500℃ Stable
≧500℃ Not stable
Tin up to 520℃ Stable
≧520℃ Not stable
Tungsten: Reaction with liquids
Substance Temperature Reaction
Water

Room
temperature

No reaction
Hot liquid No reaction
10% hydrochloric acid Room
temperature
0.0355
Heating 0.2794
Dilute sulfuric acid 110℃ 20.1168
Concentrated sulfuric acid 110℃ 0.3378
10% sulfuric acid Room
temperature
0.0203
Heating 0.1066
Concentrated sulfuric acid 110℃ 0.2870
10% nitric acid Room
temperature
18.5420
Heating 154.94
Hydrofluoric acid Room
temperature
Corrodes
10% phosphoric acid Room
temperature
0.1066
Heating 0.7721
10% acetate Room
temperature
0.0711
Heating 0.2565

Sulfuric acid

+hydrofluoric acid
  Rapidly corrodes

Sulfuric acid

+hydrochloric acid
  Rapidly corrodes

Sulfuric acid

+sulfuric acid
  Rapidly corrodes

Sodium hydroxide
≦50%

up to 100℃ Stable
Sodium hydroxide
≧50%
up to 100℃ Not stable
Ammonium hydroxide   Not stable
Potassium hydroxide
≦50%
up to 100℃ Stable
Potassium hydroxide
≧50%
up to 100℃ Not stable