Chromium (Cr) – Element Information
Atomic Symbol: Cr
Atomic Number: 24
Position in the Periodic Table:
| Group | Period | Block | Category |
|---|---|---|---|
| 6 | 4 | d-block | Transition Metal |
Occurrence:
- Not found freely in nature; primarily extracted from chromite (FeCr₂O₄).
- 21st most abundant element in Earth’s crust.
- Major producers: South Africa, Kazakhstan, India, and Turkey.
Chromium (Cr) – Occurrence & Ores
Occurrence
Metallic chromium does not occur in the free state in nature. It is always found in combined forms, primarily in minerals.
The most important ores of chromium are:
| Ore Name | Chemical Formula | Alternative Name |
|---|---|---|
| Chromite | FeCr2O4 | Iron chromium oxide |
| Chrome ochre | Cr2O3 | Chromium(III) oxide |
| Crocosite | PbCrO4 | Lead chromate |
Note: Chromite (FeCr2O4) is the most economically important ore, accounting for nearly all chromium production.
Geographical Distribution
Major chromium-producing countries include:
- South Africa (largest producer)
- Kazakhstan
- India
- Turkey
- Finland
Chromium is the 21st most abundant element in Earth’s crust.
Key Properties:
| Property | Value |
|---|---|
| Atomic Mass | 51.996 u |
| Melting Point | 1907°C (3465°F) |
| Boiling Point | 2671°C (4840°F) |
| Electron Configuration | [Ar] 3d5 4s1 |