• Sarah Hijmans

Andrés Manuel del Rio and the Two Discoveries of Vanadium

Updated: Oct 16

Vanadium, element 23, was discovered twice: first in 1801, by Del Rio in Mexico, and again in 1830 by Sefström, who gave the element its name. How could it be that an element was forgotten for almost 30 years? Why did Del Rio fail to receive recognition for his discovery? This article tells the exciting story of the discovery, loss and rediscovery of vanadium.



FIGURE 1 - Timeline of the discoveries of vanadium

Andrés Manuel Del Rio y Fernandes was born in Madrid, Spain, in 1764. After completing his studies in France, Germany and Hungary, he emigrated to Mexico City where he became professor of mineralogy at the newly founded College of Mines. In 1801, Del Rio analysed a piece of brown lead ore from a Mexican mine and found a substance that reacted unlike any other substance he knew. This meant that a new element must have been present in his sample. He called the element erythronium, after the Greek word for ‘red’, because it produced bright red compounds. A short notice was published in a Spanish journal in 1802, but Del Rio was unable to publish a full paper on the discovery: the manuscript which he addressed to the French Academy of Sciences was lost in a shipwreck on its way to Paris.


From 1803 to 1804, the German naturalist Alexander von Humboldt spent a year in Mexico. Humboldt was at the end of a large-scale expedition in South America with the French botanist Aimé Bonpland, which led to the publication of multiple volumes, establishing his international reputation in both the scientific community and the reading public. In Mexico, Humboldt studied the local nature and cultures, inspected the mines, and renewed his friendship with Del Rio, whom he knew from their time as students in Freiberg. Del Rio showed Humboldt his samples of erythronium, but Humboldt was sceptical of the discovery because of the close resemblance between the new element and chromium. Louis-Nicolas Vauquelin had announced the discovery of chromium in France in 1797; however, because of the slow communication at the time, Vauquelin’s publication did not reach Mexico City until the end of 1803. Though he was not a chemist, Humboldt was aware of Vauquelin’s work, and he knew that chromium was characterized by the formation of red salts. When Humboldt told him that the red coloration of erythronium compounds was not unique, Del Rio lost confidence in his new metal and concluded his ore must have been a lead chromate.


Nevertheless, Del Rio gave Humboldt a paper detailing his findings as well as a sample of the brown lead ore, which Humboldt passed on to Victor Collet-Descotils for analysis when he arrived back in Paris. Collet-Descotils, too, mistook erythronium for chromium. Vanadium and chromium are indeed very similar, and besides some differences in shade and solubility, they could only be separated by the fact that chromium compounds can be heated to a red vapour whereas vanadium compounds lose their red colour when heated. Collet-Descotils did notice some unusual colours in the sample, but he dismissed this as an irregularity of the reagents. He concluded that the brown lead ore contained “nothing of a new metal”. Del Rio’s paper was never published.


By the time that Collet-Descotils published his results in 1805, Del Rio had already publicly retracted his discovery. He was quite annoyed by the idea that his friend trusted the results of French chemists over his. He suspected his conclusions were ignored because they were published in Spanish. As he recalled in 1822:


“Mr. Des-Cotils has published this result in Paris in 1805, I however did so a year earlier in Mexico (…). Then again, who reads Spanish mineralogy as a pastime? Mr. Humboldt (…) doesn’t seem to have deemed the Annales de Ciencias Naturales (…) worthy of reading even once; for otherwise he would have found that in number 19 of the year 1804 I stated explicitly (…) that brown lead ore is (…) a hypo-chromate of lead. The matter was then already concluded, yet Mr. Humboldt wanted this discovery to be a foreign monopoly by all means, with the exclusion of the poor Spanish.”



FIGURE 2 - Mexico. Dirección General de Talleres de Impresión de Estampillas y Valores. Stamp Honoring Andrés Manuel Del Río.



During the following 25 years, Del Rio’s element was forgotten, but in 1830 a new discovery brought it back to light. Nils Sefström, director of the school of mining in Falun, Sweden, investigated an iron ore and found that it contained a new element, which he named ‘vanadium’ after the Scandinavian deity Vanadis (also known as Freya). In his article, Sefström warned that vanadium could easily be confused with chromium; yet, through a series of comparative tests on the oxides of these substances, he was able to show the ways in which his new element was unique.


It immediately became clear that vanadium was identical to Del Rio’s erythronium. In Germany, Friedrich Wöhler analysed Humboldt’s sample of brown lead ore. Based on a comparison with a sample of vanadium, he showed that the two metals were the same. When Del Rio heard about the rediscovery of his element, he expressed his frustration. He felt the situation could have been avoided, if only Humboldt had placed more trust in him:


“When [Humboldt] left Mexico, I (…) gave him a copy in French of my experiments so he could publish them: if he had judged them worthy of public light, they would have excited the curiosity of the chemists, and the discovery of the new metal would not have been delayed for thirty years (…).


At the time of publication of Sefström’s paper, the editors of the influential journals Annales de Chimie and the Annalen der Physik (Poggendorff, Gay-Lussac and Arago) had already been informed that vanadium was identical to Del Rio’s erythronium. For the editors, this did not diminish Sefström’s credit in any way, as they stated in a supplement to the publication:


“Mr. Sefström has (…) rendered an even bigger service to science, by discovering his metal under far more difficult conditions in a mineral product of European origin, and by being the first to prove its existence beyond any doubt.”


FIGURE 3 - A Sample of Vanadium. Copyright W. Oelen.


Del Rio rightly suspected his disadvantage as a Spanish chemist living in Mexico. Though he had a similar academic background to many of his European colleagues (he was trained by outstanding European chemists and mineralogists, and spoke German, French and English besides his native Spanish,) Del Rio had trouble inserting himself into the scientific circles. In France and Germany, few people read publications in Spanish. Moreover, he depended on a slow and fragile transatlantic communication meaning works could take years to arrive – if they were not lost at sea.


During the early 19th century, false discoveries of elements were not uncommon, and vanadium is not the only element that was retracted only to be rediscovered. Mineral analysis was one of the main activities of chemists at the time, but the extreme difficulty of telling apart the different elements that were present in mineral samples led to much confusion. However, in the case of erythronium, geographical and political factors also played a role. The discovery of a chemical element was seen as very prestigious, but Del Rio did not receive full recognition for his work. Del Rio himself felt it was unjust to give more weight to a discovery based on its origin:


“I have always been of opinion that it is of greater importance to science, that the world should concern itself more with the discoveries that are made, than with those who make them”.



Further reading

Caswell, Lyman R. 2003. “Andrés Del Rio, Alexander von Humboldt, and the Twice-Discovered Element.” Bull. Hist. Chem. 28 (1): 7.

Weeks, Mary Elvira. 1956. Discovery of the Elements. 6th ed. Easton: Journal of Chemical Education.


The citations are from:

Collet-Descotils, H.-V. 1805. “Analyse de La Mine Brune de Plomb de Zimapan, Dans Le Royaume Du Mexique, Envoyée Par M. Humboldt, et Dans Laquelle M. Del Rio Dit Avoir Découvert Un Nouveau Métal.” Annales de Chimie 53: 268–71.

Del Rio, Andrés. 1822. “Ein Paar Anmerkungen Zu Dem Handbuche Der Mineralogie von Hoffmann Fortgesetzt von Breithaupt (Über Das Braunbleierz Aus Mexico Und Die ManganBlende).” Annalen Der Physik 71: 7–12.

———. 1831. “Translation of a Letter from Professor Del Rio.” The Monthly American Journal of Geology and Natural Science 1 (1): 69–70.

———. 1832. Elementos de Orictognósia: Ó Del Conocimiento de Los Fósiles. 2nd ed. Philadelphia: Imprenta de J. F. Hurtel.

Sefström, N.-G. 1831. “Sur Le Vanadium, Métal Nouveau, Trouvé Dans Du Fer En Barres de Eckersholm, Forge Qui Tire Sa Mine de Taberg, Dans Le Smaland.” Annales de Chimie et de Physique 46: 105–11.



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