Andrés Manuel del Río y Fernández (10 November 1764 – 23 March 1849) was a Spanish scientist, naturalist and engineer who discovered compounds of vanadium in 1801. He proposed that the element be given the name panchromium, or later, erythronium, but his discovery was not credited at the time, and his names were not used.
Andrés del Río studied analytical chemistry and metallurgy in Spain, where he was born. He received his bachelor's degree from the University of Alcalá de Henares in 1780 at the age of fifteen. The government gave him a scholarship to enter the Royal Academy of Mines in Almadén, Spain, as of June 1782. He showed great aptitude. In 1783 he was given a travel grant by the Spanish Ministry of Mines. He used it to study in Paris, with the chemist Jean Darcet at the Collège de France.
Del Río continued his studies at the Mining Academy in Freiberg, Germany, under the direction of Abraham Gottlob Werner in 1789. In Freiberg he got to know Baron Alexander von Humboldt. Del Río went on to study at the Austrian Imperial-Royal Mining Academy at Schemnitz, Hungary, with Anton von Rupprecht, as well as in England.
Del Rio returned to Paris in 1791 where he was a colleague (asociado) of Antoine Lavoisier, who is considered the founder of modern chemistry, and Abbé René Just Haüy, who is considered the founder of crystallography. As a result of the French Revolution, a warrant for Lavoisier's arrest was issued on 4 November 1793. Lavoisier was executed on the guillotine on 8 May 1794. After Lavoisier's arrest, Del Río escaped to England.
In 1792, the Real Seminario de Minería (College of Mines) was founded in New Spain by a decree of King Charles III of Spain, with the object of reforming the study of mining and metallurgy in the colony. The institution was initially headed by Fausto Elhúyar (1755–1833), the discoverer of tungsten.
In 1793, Elhúyar offered Del Río a position as chair at the newly organized college. Del Rio refused the chair of chemistry, but accepted that of mineralogy.
Del Río arrived at the port of Veracruz on 20 October 1794, on the ship San Francisco de Alcántara out of Cádiz.
Once in his new position, del Río dedicated himself to teaching and scientific investigation. On 27 April 1795 he opened the first course in mineralogy ever presented in New Spain. He made important studies of minerals and developed innovative methods in mining. He also wrote the first textbook of mineralogy to be published anywhere in America, Elementos de Orictognosía, and the first in Spanish rather than German or English. Volume I appeared in 1795, and volume II in 1805. Santiago Ramírez, his student and later his biographer, described it as "a monumental work, which... will be an object of veneration and consultation".
German naturalist, Alexander von Humboldt, making a survey of resources in Spanish-held colonies for Spain, reported favorably that it was in Mexico where the best work of mineralogy in Spanish had been published, the Elementos de Orictognosia of Señor Del Rio.
Humboldt spent the period from March 1803 to March 1804 in Mexico City, renewing his friendship with del Rio and actively participating in the investigations of the College of Mining. He organized excursions to Chapultepec, to the basaltic zone of Pedregal de San Ángel, the lava fields of the Xitle volcano, and to the hot springs of Peñón de los Baños, a rocky outcrop close to the modern Mexico City International Airport, accumulating data and samples of minerals and rocks that were then submitted to chemical tests for identification.
In 1820 del Río was named a deputy to the Spanish Cortes. He was a liberal who argued for the independence of New Spain. He was in Madrid when Mexico gained its independence. Invited to remain in Spain, he nevertheless returned to Mexico (in 1821), which he considered his homeland.
"Although it is true that he was born Spanish, given the quality of his character, his sympathies, the services rendered to Mexico, and his outstanding intelligence, he was, is, and always will be Mexican."– Credited to del Rio's students
In 1829, amidst the Spanish attempts to reconquer Mexico, the government of independent Mexico expelled the Spaniards resident in the country, with some notable exceptions. Del Río was one of the exceptions. The expulsion had a major impact on the work of the College of Mining. The director, Fausto Elhúyar, was forced to resign and leave the country.
Indignant over the expulsion of his colleagues, del Río showed solidarity by himself entering voluntary exile in Philadelphia for four years. There he was highly honored. He took part in the scientific activities of the American Philosophical Society (elected 1830) and was elected president of the Geological Society of Philadelphia. John Hurtel of Philadelphia published a new edition of del Rio's book in 1832. Del Rio returned to Mexico in 1834 and again occupied the chair of mineralogy at the college. He was also given the chair of geology.
In 1801, while examining mineral samples sent to him by the Purísima del Cardenal mine in Zimapán in the State of Hidalgo, del Río arrived at the conclusion that he had found a new metallic element. He prepared various compounds of the element, and observing their diverse colors, he named the element panchromium (Greek: παγχρώμιο "all colors"). Later, on observing that the compounds changed color to red on heating, he substituted the name erythronium (Greek: ερυθρός "red").
The following year he gave samples containing the new element to Alexander von Humboldt, who sent them on to Hippolyte Victor Collet-Descotils in París for his analysis. Collet-Descotils's analysis found (mistakenly) that the samples contained only chromium. Humboldt, in turn, rejected del Río's claim of the discovery of a new element, and del Río himself concluded his discovery had been an error.
In 1830, 27 years after its initial discovery, Professor Nils Gabriel Sefström of Sweden rediscovered the element in a sample of iron of Taberg. He gave it its current name, vanadium, in honor of the Scandinavian goddess of love and beauty, Vanadis.
In the same year, Friedrich Wöhler, the German chemist who had synthesized urea, analyzed some of del Río's samples of brown lead ore of Zimapán and demonstrated that Sefström's vanadium and del Rio's erythronium were the same.