6th August 1766.

Today in 1766 William Hyde Wollaston, the polymath and discoverer of the elements Rhodium (Rh)  and Palladium (Pd) was born.

In 1803 he isolated from Platinum(Pt), the softer Palladium(Pd)- a name derived from the asteroid Pallas-after realizing it was an element in its own right.

Originally he had called Palladium after the recently discovered Ceres, after which the element Cerium was eventually named.

White gold rhodium bracelet

White gold rhodium bracelet.

Wollaston, after whom the mineral Wollastonite was named, was typical of the natural philosophers of the day being involved in physiology, astronomy. physics and chemistry.(1)

He was an early designer of electric motors, but was beaten to publication by the great Michael Faraday.

Wollaston couldn’t have foreseen that his discoveries would be used in the modern Catalytic Converters along with gold(Au), to reduce car-exhaust pollutants in the atmosphere, but at the expense of more CO2 in the exhaust.(2)

So whilst the aim is to reduce air pollutants of carbon monoxide, unburned hydrocarbons and oxides of nitrogen, global warming could be exacerbated by increased CO2 as a result of the converters, not to forget that of the increased water vapour.


Platinum dissolved by Aqua Regis.

Without chemical reactions to process and filter the exhaust pollutant into less harmful chemicals, the air would be more toxic, but at the expense of the much discussed global warming agents: a typical trade-off.

However we have simply shifted much of our air pollution to other countries such as Russia and China, producers of many of the metals and rare-earths, we use in our ‘green’ hybrid cars.

(1) Wollaston died 22.12.1828. The mineral Wollastonite is used in friction applications, brake linings and clutches, in tiling and ceramics.

(2) Three-way catalytic converters, have three similar functions: reduction of Nitrogen Oxides (Nox) by converting into elemental nitrogen and oxygen: (NO N) and O.

Next oxidation of carbon monoxide to CO2, and finally oxidation of hydrocarbons into CO2 and water.


Platinum Group (Noble Metals), are clustered in the middle of the Transition Metals, in the Periodic Table, and are highly unreactive.

They are: platinum (silvery white), iridium, osmium, palladium is silvery white and readily absorbs hydrogen, and is used as a catalyst for hydrogenation (combining with hydrogen). The other two elements, are rhodium (very hard) and ruthenium.

Platinum though generally unreactive can be dissolved using the highly acidic Aqua Regis.

Ref: chemwiki.ucdavis.edu/radox.

Ref: palladiumcoins.com/history.

Ref: wikipedia.org/Images.



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About colindunkerley

My name is Colin Dunkerley who having spent two years in the Royal Army Pay Corps ploughed many a barren industrial furrow until drawn to the 'chalk-face' as a teacher, now retired. I have spent the last 15 years researching all aspects of life in Britain since Roman times.

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