Chromium is a chemical element which has the symbol Cr and atomic number 24. It is a steel-gray, lustrous, hard metal that takes a high polish and has a high melting point. It is also odourless, tasteless, and malleable.
Technical Data
Symbol |
Cr |
Ionic radius(6-coordinate)/pm IV |
55 |
Atomic number |
24 |
Density (20°C)/gcm-3 |
7.14 |
No. of naturally occurring isotopes |
4 |
Melting point / °C |
1900 |
Atomic weight |
51.996 |
Boiling point / °C |
2690 |
Electronic configuration |
[Ar]3d54s1 |
ΔHfus/kJmol-1 |
21 (+/-2) |
Ionization energy/kJmol -1 |
653 |
ΔHvap/kJmol-1 |
342 (+/-6) |
II |
1592 |
ΔHf(monoatomic gas)/kJmol-1 |
397 (+/-3) |
III |
2987 |
Electrical resistivity |
|
Metal radius(12-coordinate)/pm |
128 |
(20°C)/ μohm cm |
13 |
Ionic radius(6-coordinate)/pm VI |
44 |
Electronegativity χ |
1.6 |
Ionic radius(6-coordinatc)/pm V |
49 |
|
|
Evaporation Techniques
Temperature (oC) @Vap. Pressure |
Techniques |
Remarks |
10-8 Torr |
10-6 Torr |
10-4 Torr |
Electron Beam |
Crucible |
Coil |
Boat |
837 Sublimes |
977 Sublimes |
1157 Sublimes |
Good |
Vitreous Graphite |
Tungsten |
Cr plated rod or strip |
Films very adherent. High rates possible. Cr plated rods are ideal for depositing Cr. |