78
Pt
Platinum
195
Platinum (Pt)
Transition MetalGroup 10Period 6d-block-block
Platinum is a chemical element with symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, gray-white transition metal. Its name is derived from the Spanish term platina, which is literally translated into "little silver".
Latin name: Platinum
Atomic Number
78
Atomic Mass
195 g/mol
Phase (STP)
Solid
Electron Config.
[Xe] 4f¹⁴ 5d⁹ 6s¹
General
SymbolPt
Atomic Number78
Atomic Mass195 g/mol
CategoryTransition Metal
Group10
Period6
Blockd-block
Electron Configuration[Xe] 4f¹⁴ 5d⁹ 6s¹
Valence Electrons10
Coloursilvery-white metallic
Appearancesilvery white
CAS NumberCAS7440-06-4
Physical Properties
Phase (STP)Solid
Density21.45 g/cm³
Melting Point1768.25°C · 3214.85°F · 2041.40 K
Boiling Point3824.85°C · 6916.73°F · 4098.00 K
Atomic Properties
Atomic Radius209 pm
Electronegativity2.28 Pauling
Ionization Energy870 kJ/mol
Oxidation States+2, +4, +6
Ion ChargePt2+/Pt4+/Pt6+
Thermodynamic
Molar Heat25.86 J/(mol·K)
Crystal Structure
Crystal Structureface-centered cubic
Mechanical Properties
Mohs Hardness4.5
Nuclear & Hazards
Half-lifestable
Abundance
In Universe0.000006%
In Sun0.000005%
In Earth's Crust0.00005%
Discovery & History
Discovered Byknown to pre-Columbian Americans; described in Europe in 16th century
Isotopes of Platinum
| Isotope | Abundance | Half-life | Decay |
|---|---|---|---|
| Pt-190 | 0.012% | 6.5 × 10¹¹ years | α |
| Pt-192 | 0.782% | Stable | — |
| Pt-194 | 32.967% | Stable | — |
| Pt-195 | 33.832% | Stable | — |
| Pt-196 | 25.242% | Stable | — |
| Pt-198 | 7.163% | Stable | — |