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Rediscovery of the Elements
Columbium and Tantalum
James L. Marshall, Beta Eta 1971, and
Virginia R. Marshall, Beta Eta 2003,
Department of Chemistry, University of
North Texas, Denton,TX 76203-5070,
jimm@unt.edu
Charles Hatchett (1765-1847), a prosperous
London coach-builder and avocational
chemist, discovered columbium (niobium) in
1801. The following year, Anders Gufstaf
Ekeberg (1767-1813), professor of chemistry at
the University of Uppsala, Sweden, discovered
tantalum. Because of the chemical similarity of
the two metals (both 5B members of the
Periodic Table), they were believed to be the
same element for half a century (Figure 1).
Figure 1. Charles Hatchett (left) discovered
columbium (today known as niobium) in 1801
(engraving by F. C. Lewis after Thomas Phillips'
painting, now lost), and Anders Ekeberg (right)
discovered tantalum the following year (engraving
by A. U. Berndes, after a drawing by J. E. Roos).
Wollaston's work in 1809 suggested the two
elements were identical, and Hatchett and Ekeberg
died never knowing they had in fact discovered
different elements.
Figure 2. Hatchett's
coach-making Hatchett's gin
business was located HatLondon cheCenral
at 121 Long Acre London C n rl
(N510 30.76 WO0 Hyde Park
07.52). Charles Ha .rs I ha e
spent his youth in o. l -
Belle Vue in Chelsea eva a dens el Ous
(owned by his uver
father) and then C e sea,
repurchased the 2
home for his final
years (91-92
Cheyne Walk; N51 Roe ampt n Wimbledon
28.92 WOO 10.45). unt C 3 km
Charles Hatchett's
first home after his marriage was at the Lower Mall in Hammersmith at an address today unknown; this
area was bombed in World War II and is now occupied by Furnival Gardens (N510 29.42 WOO 13.99);
this is where he discovered columbium. Also in Hammersmith may be found today at Hop Poles Inn (17-19
King Street, N51 29.56 WOO 13.55), a favorite haunt of Charles Hatchett. In mid-life his home was
Mount Clare (1808-1819) at Minstead Gardens, Roehampton (N510 27.11 WOO 15.04).
Charles Hatchett' (Figure 2) was born at his
father's carriage manufactory on Long Acre
(Figure 3). Charles, being the only son, had
financial resources for pursuing many hobbies,
including music, art, travel, and the sciences.
Charles married Elizabeth Martha Collick
(1756-1837), daughter of a wigmaker. They
traveled for two years in Poland and Russia and
then returned to Hammersmith, where his
father had extensive property (Figure 4). In
1790 Charles was sent to St. Petersburg to
deliver a coach to Catherine the Great. During
this trip, he made extensive visits to scientists,
mines, and mineral collections. One of these
scientists was Martin Klaproth in Berlin, the
discoverer of uranium.2g Absorbed in his new
passion of chemistry and mineralogy, Hatchett
continued his scientific tours through Europe
and by 1796 published his first paper, a signifi-
cant analysis of lead molybdatea (distinguish-
ing it from lead tungstate). He became a mem-
ber of the Royal Society, the Royal Institution
(to which he frequently made donations), the
Linnean Society, and the Mineralogical Society.
In the world of chemistry Hatchett seemed
to have a sense for knowing what might be
important to investigate. His first paper on lead
molybdate3a was deemed important enough to
merit his election to the Royal Society. His work
with bones and shells'" first determined the dif-
ferent compositions of bones and teeth (mostly
calcium phosphate) and shells (mostly calcium
carbonate).3 But his most important discovery
was columbium (niobium).
The discovery of columbium. The discov-
ery of this element was prompted by Hatchett's
curiosity regarding a certain ore in the British
Museum. As he was arranging specimens in
this museum's mineral collection, he noted a
"heavy black stone" originating from "Mr.
Winthrop, of Massachusetts."" Hatchett chose
well-this was a relatively pure sample of
columbite, with the (ideal) composition
(Fe,Mn)Nb206, ready for a straightforward
chemical analysis.
Hatchett, in his Hammersmith home/labo-
ratory (Figure 5), took 200 grains (13.0 grams)
of the sample and reacted with "carbonate of
potash" at "red heat." The resulting grayish-
brown mass was taken up in boiling distilled
water and treated with nitric acid, whereupon a
"copious, white flocculent precipitate" was
thrown down. The filtrate was proven to be
"chiefly of iron"by (1) its reaction with"prussi-
ate of potassium" (potassium ferrocyanide) to
THE HEXAGON/SUMMER 2013