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Discovery histories

How familiar materials became chemical knowledge—and how that knowledge changed the world.

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18 discovery histories

1740–1774

A familiar black mineral, an unfamiliar metal

Manganese became an element through chemical investigation and metal isolation, long after people had learned to use its ores.

Mn O C Fe

Early 1770s–1789

The gas that changed the explanation of fire

Scheele and Priestley prepared an unusual gas; Lavoisier and his collaborators helped make it central to a different chemical system.

O Hg C H

1807–1808

A battery takes elements out of their compounds

Within two years a new electrical method released six elements that chemical reagents had never freed, because the compounds holding them were too stable to break by chemistry alone.

K Na Ca Sr Ba Mg

1803–1844

Four metals found in a residue

Dissolving crude platinum left an insoluble residue that most analysts discarded. Two who examined it instead found four new elements in it.

Pd Rh Os Ir Pt Ru

1864–1913

How an ordering became a predictive system

Meyer and Mendeleev recognized recurring chemical behavior; Moseley later connected an element’s position to measurable atomic structure.

C Si Ga Ge Te I

1859–1875

Elements found by their colors

Once a flame’s light could be spread into sharp lines and matched against a catalog, an element could be detected before anyone had a weighable sample of it.

Cs Rb Tl In Ga He

1892–1898

The missing ingredients of ordinary air

A small density discrepancy opened a new column of the periodic table through the combined work of physicists and chemists.

He N Ne Ar Kr Xe

1896–1910

When a mineral was more active than its uranium

Photographic effects and electrical measurements led from unexpected uranium rays to evidence for previously unknown elements.

U Th Po Ra

1794–1907

Fourteen elements hidden in one mineral

The rare earths were separated from one another over more than a century, because chemically similar elements resist the methods that separate ordinary ones.

Ce La Pr Nd Sm Eu

1923–1956

Reading the stars without confusing brightness with abundance

Cecilia Payne connected stellar spectra with atomic physics to reveal the dominance of hydrogen and helium.

H He Ca Fe

1781–1928

Metals that will not melt

Tungsten, molybdenum, tantalum, niobium and hafnium were hard to discover for the same reason they became indispensable: their compounds are stubborn and the metals themselves resist heat.

Mo W Ta Nb Hf Re

1898–1935

Elements that arrive by decay

Several elements were first found as short-lived members of radioactive series, and explaining them forced chemists to accept that one place in the table can hold atoms of different mass.

Po Ra Rn Ac Pa Fr