Category: Transition metal
Atomic Number: 24
Period: 4 | Group: 6
Block: d-block
The element that puts the shine in chrome and the "stainless" in stainless steel.
| Property | Value |
|---|---|
| Phase at STP | Solid |
| Density | N/A |
| Melting Point | 2180.00 K (1906.85 °C) |
| Boiling Point | 2944.00 K (2670.85 °C) |
| Heat Capacity | N/A |
| Property | Value |
|---|---|
| Atomic Mass | 51.9961 u |
| Electronegativity (Pauling) | N/A |
| Oxidation States | -2, -1, 0, +2, +3, +4, +5, +6 |
| Electron Configuration |
| Discovered By | Unknown |
|---|---|
| Discovery Year | 1797 |
| Named After | Greek chroma, "colour" |
The Colorful Discovery
Louis-Nicolas Vauquelin discovered chromium in 1797 while analyzing crocoite mineral (PbCrO₄) from Siberian gold mines. The mineral's brilliant orange-red color intrigued Vauquelin, leading him to isolate a new metallic element he named "chromium" from the Greek word "chroma" meaning color, reflecting the vivid hues of chromium compounds.
Industrial Development
Commercial chromium production began with ferrochrome smelting in the 1890s, enabling stainless steel development. Harry Brearley's 1913 discovery of stainless steel in Sheffield, England, transformed chromium demand and established the foundation for modern chromium metallurgy.
| ISOTOPE | Neutrons | Natural Abundance | Half-life | Decay Mode |
|---|---|---|---|---|
| Cr-50 | 26 | 4.345% | >1.3 × 10¹⁸ yrs | 2ε |
| Cr-51 | 27 | - | 27.704 days | ε |
| Cr-52 | 28 | 83.789% | Stable | - |
| Cr-53 | 29 | 9.501% | Stable | - |
| Cr-54 | 30 | 2.365% | Stable | - |
Data: IAEA Nuclear Data Section, LiveChart of Nuclides, ground-state evaluations, retrieved October 10, 2026. Abundance is the share of atoms in the natural element; a dash means the isotope has no standard natural abundance.
Chromium: The Mirror Maker
Chromium transforms ordinary steel into stainless perfection while creating the brilliant mirrors and decorative finishes that define modern aesthetics. This transition metal's unique properties enable everything from surgical instruments to spacecraft heat shields.
Stainless Steel
Austenitic stainless steels containing 16-26% chromium form protective oxide layers that self-heal when scratched, providing permanent corrosion resistance. Type 316 stainless steel withstands marine environments, chemical processing, and medical applications through chromium's passivation properties. Global stainless steel production consumes 85% of chromium supply, enabling corrosion-resistant infrastructure from kitchen appliances to chemical plants.
Decorative Chrome Plating
Electroplating processes deposit ultra-thin chromium layers (0.25-2.5 μm) that create mirror-bright finishes on automotive trim, plumbing fixtures, and decorative hardware. Hard chrome plating applies thicker deposits (25-250 μm) for industrial applications requiring high wear resistance, including hydraulic cylinders, machine tool ways, and printing rolls.
Refractory Applications
Chromite bricks line steel furnaces and glass melting tanks, withstanding temperatures exceeding 1800°C while resisting slag corrosion. Chrome-magnesite refractories enable cement kiln operation and non-ferrous metal smelting through chromium oxide's exceptional thermal stability and chemical inertness.
Pigment Technology
Chrome oxide green (Cr₂O₃) provides permanent color for ceramics, paints, and plastics with exceptional UV stability and chemical resistance. Lead chromate pigments create brilliant yellows and oranges for industrial coatings, though environmental regulations limit their use to specialized applications.
| Earth's Crust | N/A |
|---|---|
| Universe | N/A |