section_path: Natural sciences/Chemistry
section_name: Chemistry
paragraph_text: Chemistry
  
  The early Islamic period saw the establishment of some of the longest lived theoretical frameworks in alchemy and chemistry. The sulfur-mercury theory of metals, first attested in pseudo-Apollonius of Tyana's Sirr al-khalīqa ("The Secret of Creation", c. 750–850) and in the Arabic writings attributed to Jābir ibn Ḥayyān (written c. 850–950), would remain the basis of all theories of metallic composition until the eighteenth century. Likewise, the Emerald Tablet, a compact and cryptic text that all later alchemists up to and including Isaac Newton (1642–1727) would regard as the foundation of their art, first occurs in the Sirr al-khalīqa and in one of the works attributed to Jābir.
  
  Substantial advances were also made in practical chemistry. The works attributed to Jābir, and those of the Persian alchemist and physician Abū Bakr al-Rāzī (c. 865–925), contain the earliest known systematic classifications of chemical substances. However, alchemists were not only interested in identifying and classifying chemical substances, but also in artificially creating them. Significant examples from the medieval Islamic world include the synthesis of ammonium chloride from organic substances as described in the works attributed to Jābir, and Abū Bakr al-Rāzī's experiments with vitriol, which would eventually lead to the discovery of mineral acids like sulfuric acid and nitric acid by thirteenth century Latin alchemists such as pseudo-Geber.