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Features of molybdenum

What is molybdenum?

1High melting point

High melting point

Molybdenum possesses the fifth highest melting point among all metals. It features a low thermal expansion coefficient and exceptional shape stability, even in high-temperature environments.

2Large electric resistance

Large electric resistance

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

3Easy workability

Easy workability

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

Hard, silver-white molybdenum, named after 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. Utilizing its characteristics – high melting point, excellent mechanical features, and relatively easy workability compared to tungsten – it is an indispensable metal in various applications, including ribbon and wire in the field of lighting, 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 power electronics.

Molybdenum physical properties
Atomic number *1 42
Element symbol Mo
Density
(Mg/m3*2
293K 10.2
Melting point(K)*2 2903±10
Boiling point(K)*2 5100
Electrical Resistance
(10-8Ωm)*2
293K 5.7
Specific heat
(J/kgK)*2
273-373K 251
Thermal conductivity
(W/mK)*2
273-373K 137
Coefficient of Linear Expansion
(10-6/K)*2
293-373K
293-1773K
5.2
6.51
Work function
(eV)*2
4.2
Thermal neutron capture cross section area
(barns/atom)*3
2.4±0.02
*1 Standard Atomic Weights (2017), The Chemical Society of Japan
*2 Fourth Edition of Metal Data Book, The Japan Institute of Metals and Materials
*3 Materials and techniques for electron Tubes,Walter H.Kohl (1960)

Chemical properties

  • In the air, oxidation begins at room temperature and proceeds considerably at dark red temperatures.
  • Molybdenum does not react at room temperature with dry oxygen, but it rapidly oxidizes at 500℃ or higher and evaporates at temperatures of 650℃ or higher, turning into MoO₃ of a white mouse color.
  • It reacts easily with sulfur, carbon, or silicon at high temperatures to produce MoS₂, Mo₂C, MoSi₂, and others.
  • It reacts very little at 1 atm; however, nitride can be synthesized by heating under high pressure (>15 atm).
  • It has a strong affinity for arsenic.
  • It exhibits little corrosion in hydrofluoric acid, hydrochloric acid, and sulfuric acid at 20℃, but shows significant corrosion 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 ≦2,400℃ Hardly to react (1atm)
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
Molybdenum: 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 20℃ Hardly to react
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
* Corrosion rate (mm/year)