Platinum commonly forms Pt2+ Pt4+ in introductory ionic compounds.
| Element | Platinum |
|---|---|
| Symbol | Pt |
| Atomic number | 78 |
| Common ionic charge | +2, +4 |
| Common ions | Pt2+, Pt4+ |
Images are used as visual references; charge rules still depend on the compound.
Platinum is [Xe]4f14 5d9 6s1. The d8 Pt2+ state adores square-planar geometry — four ligands in a plane, the shape that lets cisplatin clamp DNA — while d6 Pt4+ prefers octahedral. Relativistic effects strengthen its bonds, making complexes famously slow to swap partners, a kinetic patience drug designers exploit.
This is a classroom reference range, not an exhaustive list of all oxidation states.
Assuming the +2/+4 numerals work like iron's 2/3 in simple salts. Platinum's compounds are essentially all complexes: 'platinum(IV) chloride' in solution promptly becomes PtCl6 2-. Count ligands and overall charge, not just the metal's numeral.
Ammonia ligands are neutral; two Cl- give -2; the drug molecule is neutral overall, so Pt = +2. In the body it trades chlorides for DNA nitrogen atoms — same +2, new partners, cancer cell cycle halted.
Platinum chloride
Pt2+ balances chloride ions.
Platinum oxide
Platinum can form oxides where total positive and negative charge balances.
Silver's +1 chemistry welcomes sulfur; platinum's ionization costs are high enough that skin, air, and chlorinated pools leave it at charge 0 indefinitely. Nobility is expensive ionization, priced accordingly.
Zero — nanoparticles of the neutral metal split H2 and O2 on their surfaces. Engineers' entire cost battle is using fewer charge-0 platinum atoms per kilowatt.
The old standard kilogram (retired 2019) was 90% platinum, 10% iridium — chosen precisely because both metals' reluctance to ionize meant the cylinder would neither corrode nor grow. Charge stability as metrology.
Combine positive and negative ions so the total charge is zero — or let the ionic compound calculator do the crossing for you. The full chart lives on the periodic table with charges.
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