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Al-Razi, Abu-Bakr Muhammed ibn Zakariya

Al-Razi, Abu-Bakr Muhammed ibn Zakariya

ca. 854 930 c.e.

Abu-Bakr Muhammed ibn Zakariya al-Razi (also transliterated as ar-Razi) was born around 854 in Ray, near the city of Teheran (the Persian Empire, now Iran). Al-Razi (in the Latinized West, Rhazes) achieved mastery in a number of fields, including philosophy, logic, poetry, and music. Around the age of thirty he left Ray for Baghdad (now in Iraq), where he was active in the reconstruction of the city hospital. Al-Razi became famous as the most prominent physician in the Islamic world, his fame comparable only to that of another Persian physician, Ibn Sina (who became known in the West as Avicenna). Al-Razi's written works in medicine have been widely studied, Latin editions of which remained in use as late as the seventeenth century in Europe. From him we have the earliest distinction between smallpox and measles, and the understanding that smallpox occurs only once in a person's life. As a skilled chemist he recognized the toxicity of arsenic (arsenic oxide), but prescribed small doses of this compound in the treatment of many skin diseases and anemia.

Like his predecessor, the Arabian alchemist Jabir ibn Hayyan (sometimes known as Jabir), al-Razi was influenced in his alchemical views by Aristotle's theory of the four elements. Arabic alchemists had modified the Aristotelian system with respect to the composition of minerals, whereby two elements, mercury and sulfur, were responsible for "the mercurial and sulfurous principles" of a given substance. Later called "philosophical" Mercury and Sulfur, these elements (or principles) were thought to be the substances from which all metals were formed. This Sulfur-Mercury theory later became highly influential among European thinkers, for example, Isaac Newton. To this Sulfur and Mercury, al-Razi added a third constituent, a salty principle (which was later reproposed by Paracelsus). In al-Razi's opinion metals were comprised of particles of these elemental constituents, while the identity of the metal depended on the relationships between these indivisible particles and the empty spaces between them.

In contrast to Jabir, who inclined toward numerical mysticism, al-Razi became practiced in experimental work. This is apparent from his two most influential works, Kitab al-Asrar (The Book of Secrets ), and Kitab sirr al-Asrar (The Book of the Secret of Secrets ). In these works he gave several recipes for the alleged transmutation of common metals into precious ones, and crystal or glass into precious stones. Perhaps al-Razi's main contribution to chemistry was his attempt to systematize laboratory practices, to which end he listed contemporary laboratory equipment and techniques used in chemical experiments. Another influential contribution to chemistry was his classification of all the chemical substances he knew, for this is the earliest attempt of which we are aware. Al-Razi divided these substances into four main groups: vegetable, animal, derivative, and mineral. The last group consisted of six subgroups: (1) spirits (volatile substances, such as mercury, sulfur, and arsenic sulfide); (2) metals (gold, silver, copper, tin, iron, lead, and "karesin," probably a bronze composed of copper, zinc, and nickel); (3) stones (ores and minerals of iron, copper, zinc, but also glass); (4) atraments (metallic sulfates and their derivatives); (5) boraces (borax, but also sodium carbonate [confused with borax]); and (6) salts (in which categorization sodium chloride appears under four different terms, other salts being sodium carbonate, potassium carbonate, and others).

In later life al-Razi became blind, which, according to some sources, was a result of his indefatigable activityfor he is said to have written approximately 200 works. According to other sources his blindness was a result of torture, the punishment he was given when he failed to produce precious metals via alchemical transmutation. Al-Razi died in 925 or 935 in Ray.

see also Newton, Isaac; Paracelsus.

Vladimir Karpenko


Garbers, Karl, and Weyer, Jost (1980). Quellengeschichtliches Lesebuch zur Chemie und Alchemie der Araber im Mittelater. Hamburg: H. Buske Verlag.

Heym, Gerard (1938). "Al-Razi and Alchemy." Ambix 1:184191.

Holmyard, Eric J. (1990). Alchemy. New York: Dover Publications.

Newman, William R. (1991). The Summa Perfectionis of Pseudo-Geber. A Critical Edition, Translation and Study. Leiden: E. J. Brill.

Partington, J. R. (1938). "The Chemistry of Razi." Ambix 1:192196.

Internet Resources

Zahoor, A. "Abu Bakr Muhammad Bin Zakariya ar-Razi." Available from <>

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