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Image of Alchimia, the embodiment of alchemy. Woodcut published by Leonhard Thurneysser in 1574. Thurneysser was a student of Paracelsus. Alchimia.gif
Image of Alchimia, the embodiment of alchemy. Woodcut published by Leonhard Thurneysser in 1574. Thurneysser was a student of Paracelsus.

Alkahest is a hypothetical "universal solvent": able to dissolve every other substance, including gold. The famous alchemist Philippus Paracelsus described alkahest in the 1500s. Because of its perceived invaluable medicinal qualities, Alchemists of the time were concerned with its plausibility and existence.

Solvent substance that dissolves a solute (a chemically different liquid, solid or gas), resulting in a solution

A solvent is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. The quantity of solute that can dissolve in a specific volume of solvent varies with temperature. Common uses for organic solvents are in dry cleaning, as paint thinners, as nail polish removers and glue solvents, in spot removers, in detergents and in perfumes (ethanol). Water is a solvent for polar molecules and the most common solvent used by living things; all the ions and proteins in a cell are dissolved in water within a cell. Solvents find various applications in chemical, pharmaceutical, oil, and gas industries, including in chemical syntheses and purification processes.

Solubility Capacity of a designated solvent to hold a designated solute in homogeneous solution under specified conditions

Solubility is the property of a solid, liquid or gaseous chemical substance called solute to dissolve in a solid, liquid or gaseous solvent. The solubility of a substance fundamentally depends on the physical and chemical properties of the solute and solvent as well as on temperature, pressure and presence of other chemicals of the solution. The extent of the solubility of a substance in a specific solvent is measured as the saturation concentration, where adding more solute does not increase the concentration of the solution and begins to precipitate the excess amount of solute.

Gold Chemical element with atomic number 79

Gold is a chemical element with the symbol Au and atomic number 79, making it one of the higher atomic number elements that occur naturally. In its purest form, it is a bright, slightly reddish yellow, dense, soft, malleable, and ductile metal. Chemically, gold is a transition metal and a group 11 element. It is one of the least reactive chemical elements and is solid under standard conditions. Gold often occurs in free elemental (native) form, as nuggets or grains, in rocks, in veins, and in alluvial deposits. It occurs in a solid solution series with the native element silver and also naturally alloyed with copper and palladium. Less commonly, it occurs in minerals as gold compounds, often with tellurium.



The name is believed to have been invented by Paracelsus from Switzerland, who modeled it on similar words taken from Arabic, such as "alkali". Paracelsus' own recipe was based on caustic lime, alcohol, and carbonate of potash. [1] He believed that alkahest was, in fact, the philosopher's stone.

Paracelsus Swiss physician and alchemist

Paracelsus, born Theophrastus von Hohenheim, was a Swiss physician, alchemist, and astrologer of the German Renaissance.

Switzerland federal republic in Central Europe

Switzerland, officially the Swiss Confederation, is a sovereign state situated in the confluence of western, central, and southern Europe. It is a federal republic composed of 26 cantons, with federal authorities seated in Bern. Switzerland is a landlocked country bordered by Italy to the south, France to the west, Germany to the north, and Austria and Liechtenstein to the east. It is geographically divided between the Alps, the Swiss Plateau and the Jura, spanning a total area of 41,285 km2 (15,940 sq mi), and land area of 39,997 km2 (15,443 sq mi). While the Alps occupy the greater part of the territory, the Swiss population of approximately 8.5 million is concentrated mostly on the plateau, where the largest cities are located, among them the two global cities and economic centres of Zürich and Geneva.

In chemistry, an alkali is a basic, ionic salt of an alkali metal or alkaline earth metal chemical element. An alkali also can be defined as a base that dissolves in water. A solution of a soluble base has a pH greater than 7.0. The adjective alkaline is commonly, and alkalescent less often, used in English as a synonym for basic, especially for bases soluble in water. This broad use of the term is likely to have come about because alkalis were the first bases known to obey the Arrhenius definition of a base, and they are still among the most common bases.

Issues with the concept

A potential problem involving alkahest is that, if it dissolves everything, then it cannot be placed into a container because it would dissolve the container. However, the alchemist Philalethes specified that alkahest dissolved only composed materials into their constituent, elemental parts; [2] hence, a hypothetical container made of a pure element (say, lead) would not be dissolved by alkahest. The old remark "spit is the universal solvent" satirizes the idea, suggesting that instead of a solvent that would easily dissolve anything, the only "real" solvent to anything is a great deal of hard work. In modern times, water is sometimes called the universal solvent, because it can dissolve a large variety of substances, due to its chemical polarity and amphoterism.

Water Chemical compound with formula H2O

Water is a transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's streams, lakes, and oceans, and the fluids of most living organisms. It is vital for all known forms of life, even though it provides no calories or organic nutrients. Its chemical formula is H2O, meaning that each of its molecules contains one oxygen and two hydrogen atoms, connected by covalent bonds. Water is the name of the liquid state of H2O at standard ambient temperature and pressure. It forms precipitation in the form of rain and aerosols in the form of fog. Clouds are formed from suspended droplets of water and ice, its solid state. When finely divided, crystalline ice may precipitate in the form of snow. The gaseous state of water is steam or water vapor. Water moves continually through the water cycle of evaporation, transpiration (evapotranspiration), condensation, precipitation, and runoff, usually reaching the sea.

Chemical polarity eltectrostatic property of a molecule

In chemistry, polarity is a separation of electric charge leading to a molecule or its chemical groups having an electric dipole moment, with a negatively charged end and a positively charged end.

In chemistry, an amphoteric compound is a molecule or ion that can react both as an acid and as a base. Many metals (such as copper, zinc, tin, lead, aluminium, and beryllium) form amphoteric oxides or hydroxides. Amphoterism depends on the oxidation states of the oxide. Al2O3 is an example of an amphoteric oxide.

Paracelsus's successor

A later alchemist, Franciscus Mercurius van Helmont, picked up where Paracelsus had left off. In his major texts he also gave attention to transmutation of metals, to techniques for separating the pure from the impure parts of nature, and, of special significance, to a substance, called the liquor alkahest, which he accepted as one of the greatest secrets of Paracelsus and which he referred to as incorruptible dissolving water that could reduce any body into its first matter.

Franciscus Mercurius van Helmont Flemish alchemist and writer

Franciscus Mercurius van Helmont was a Flemish alchemist and writer, the son of Jan Baptist van Helmont. He is now best known for his publication in the 1640s of his father's pioneer works on chemistry, which link the origins of the science to the study of alchemy.

Van Helmont's writings pointed to even earlier medieval descriptions of a substance called sal alkali. Sal alkali, in turn, appears to have been a solution of caustic potash in alcohol, which dissolves many substances. Helmont described a process in which his alkahest (sal alkali) was applied to olive oil. The result was identified as a sweet oil, which was glycerol. [3]

Glycerol chemical compound

Glycerol is a simple polyol compound. It is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. The glycerol backbone is found in many lipids which are known as glycerides. It is widely used as a sweetener in the food industry and as a humectant in pharmaceutical formulations. Glycerol has three hydroxyl groups that are responsible for its solubility in water and its hygroscopic nature.

See also

Electrolysis technique that uses a direct electric current to drive an otherwise non-spontaneous chemical reaction

In chemistry and manufacturing, electrolysis is a technique that uses a direct electric current (DC) to drive an otherwise non-spontaneous chemical reaction. Electrolysis is commercially important as a stage in the separation of elements from naturally occurring sources such as ores using an electrolytic cell. The voltage that is needed for electrolysis to occur is called the decomposition potential.


Azoth was considered to be a universal medication or universal solvent, and was sought for in alchemy. Similar to another alchemical idealized substance, alkahest, azoth was the aim, goal and vision of many alchemical works. Its symbol was the Caduceus. The term, while originally a term for an occult formula sought by alchemists much like the philosopher's stone, became a poetic word for the element mercury. The name is Medieval Latin, an alteration of azoc, being originally derived from the Arabic ''al-zā'būq'', "the mercury".

Aqua regia mixture

Aqua regia is a mixture of nitric acid and hydrochloric acid, optimally in a molar ratio of 1:3. Aqua regia is a yellow-orange fuming liquid, so named by alchemists because it can dissolve the noble metals gold and platinum, though not all metals.


  1. Paracelsus' recipe is popular with chemists even today; a bath of potassium hydroxide in ethanol leaves laboratory glassware sparkling clean
  2. Philalethes, Eirenaeus. "The Secret of the Immortal Liquor Called Alkahest or Ignis-Aqua" . Retrieved 14 May 2014.
  3. Leinhard, John. "No.1569 Alkahest". University of Houston. Retrieved 14 May 2014.

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Base (chemistry) substance that can accept hydrogen ions (protons) or more generally, donate a pair of valence electrons

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Philosophers stone Legendary alchemical substance

The philosopher's stone, more properly philosophers' stone or stone of the philosophers is a legendary alchemical substance capable of turning base metals such as mercury into gold or silver. It is also called the elixir of life, useful for rejuvenation and for achieving immortality; for many centuries, it was the most sought goal in alchemy. The philosophers' stone was the central symbol of the mystical terminology of alchemy, symbolizing perfection at its finest, enlightenment, and heavenly bliss. Efforts to discover the philosophers' stone were known as the Magnum Opus.

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Ammonium hydroxide, also known as ammonia water, ammonia solution, ammoniacal liquor, ammonia liquor, aqua ammonia, aqueous ammonia, or (inaccurately) ammonia, is a solution of ammonia in water. It can be denoted by the symbols NH3(aq). Although the name ammonium hydroxide suggests an alkali with composition [NH4+][OH], it is actually impossible to isolate samples of NH4OH. The ions NH4+ and OH do not account for a significant fraction of the total amount of ammonia except in extremely dilute solutions.

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Solvolysis is a type of nucleophilic substitution (SN1) /( SN2) or elimination, where the nucleophile is a solvent molecule. Characteristic of SN1 reactions, solvolysis of a chiral reactant affords the racemate. Sometimes however, the stereochemical course is complicated by intimate ion pairs, whereby the leaving anion remains close to the carbocation, effectively shielding it from an attack by the nucleophile. Particularly fast reactions can occur by neighbour group participation, with nonclassical ions as intermediates or transition states.


Iatrochemistry is a branch of both chemistry and medicine. Having its roots in alchemy, iatrochemistry seeks to provide chemical solutions to diseases and medical ailments.

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Stain removal is the process of removing a mark or spot left by one substance on a specific surface like a fabric. A solvent or detergent is generally used to conduct stain removal and many of these are available over the counter.

Recrystallization (chemistry) separation process

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Isidore (inventor)

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