Chimica Arcana

To grasp the invisible elements, to attract them by their material correspondence, to control, purify and transform them by the living power of the spirit, this is true alchemy. 

~Paracelsus (1493-1541)

Before any sort of chemical bonding was even thought of there were charts of so-called affinities.  I found this interesting chart dating from 1718 on Wiki. It teaches how the then-known "elements" combined with each other. The top row identifies an element and the columns contain those elements with which it combines. Note that sulfur (middle column) was considered the most promiscuous element, consistent with its primacy as the "soul" of matter according to alchemy. Also bear in mind that this simple chart condenses the then known science of chemisty, ca. 1718.  I like the arcane symbols and could see using some them as avatars depending on my mood:

Click to enlarge or see link above

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Here are my translations of the "elements."

Esprit acides : Acidic (acerbic) spirits

Acide du sel marin: Lit. acid of sea salt, HCl (which was thought to contain oxygen until Davy showed otherwise: link)

Acide nitreux: Nitric and nitrous acids, HNO₃, HNO₂

Acide vitriolique: Sulfuric and sulfurous acids, derived from oleum & vitriol.

Sel alcali fixe: Sodium & potassium hydroxides and carbonates.

Sel alcali volatil: Sal ammoniac, NH₄Cl, which sublimed and was endlessly fascinating.

Terre absorbante: Silicates (sand) and diatomaceous earth.

Substances metalliques: Metallic substances

Mercure: Mercury was considered to be the spirit of matter.

Regule d'Antimoine: Regulus of antimony--metallic antimony. Regulus means "little King"

Or: Gold

Argent: Silver

Cuivre: Copper

Fer: Iron

Plomb: lead

Etain: Tin

Zinc

Pierre Calaminaire: Lit. calamine stone, i.e., calamine ore. Note the French place name.

Soufre mineral: Sulfur or brimstone.  This material held a special place in alchemy, along with mercury and salt.

Principe huileux ou Soufre: The oily essence of organic substances from plants, also called the "sulfur." See the interesting discussion under Spagyric.

Esprit de vinaigre: Vinegar or acetic acid

Eau: water

Sel: Salt held a special place in alchemy along with mercury and sulfur.  

Esprit de vin et Esprit ardents: Any of the flammable alcohols derived from fermentation, e.g., ethanol, methanol, etc.

Synthesis v. Analysis

Around the time that America began civil warfare, reports of a new chemical element came from the relative tranquility of Germany. Robert Bunsen and Gustav Kirchhoff reported in 1861:

Supported by unambiguous results of the spectral-analytical method, we believe we can state right now that there is a fourth metal in the alkali group besides potassium, sodium, and lithium, and it has a simple characteristic spectrum like lithium; a metal that shows only two lines in our apparatus: a faint blue one, almost coinciding with strontium, and another blue one a little further to the violet end of the spectrum and as strong and as clearly defined as the lithium line.

They had discovered cesium which they named after the Latin word meaning "sky blue." 

There had been a 15 year lull in finding new chemical elements between about 1845 and 1860. One reason for this was that many of the "easy" elements had already been exhumed in measurable enough quantities. Here is a timeline of element discovery: link 

The mid-19th century saw advances in both chemical synthesis and chemical analysis. Chemical synthesis, obviously, involves putting things together; analysis means tearing substances down to find out what's there (the same dichotomy exists in writing).

Decades before Bunsen and Kirchoff, Humphry Davy proved the existence of new chemical elements by making them: he electrolyzed sodium and potassium salts, reducing Na⁺ and K⁺ cations to their neutral metals.*  Now Bunsen and Kirchhoff had shown the same level of proof through analysis without synthesizing the new element. This paradigm shift was profound and rapidly accelerated the discovery of newer elements (see the timeline).  The next few newly-discovered elements were all named for their unique colors in flame spectra.

Around the same time as Bunsen and Kirchoff, the nascent science (really art) of organic chemistry still lagged because there was no convincing method of analysis which could prove a new organic compound.  There was only combustion analysis--invented in the 1820s by Joseph Louis Gay-Lussac and Justus von Liebig--which involved burning a sample to determine its carbon, hydrogen, and nitrogen ratios.  And so, for the time being, the proof of a new organic compound's structure found in nature lay in making it synthetically. Thus began a long and rich tradition of synthetic organic chemistry. It took until the end of the Second World War for analytical methods to catch up.
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*The verb "to reduce," in the chemical sense, derives from Latin using the notions of re + ducere = to lead back to (the element).

Think Zinc!

Elemental zinc is used like electronic paint. The element is always found as Zn²⁺, but it may be coaxed into taking back two electrons. The word "zinc" entered the lexicon via German, Zink, presumably when it was discovered by alchemists. The usual sources viz., van der Krogt and the OED are silent regarding a hunch of mine--that it was so named because of its toothy appearance. My trusty Duden Vol 7 confirms that the word Zink is distantly related to the German word for tooth, Zahn--apparently from the metal's appearance when freshly prepared.

We've all seen how zinc appears when coated on sheet metal. The pattern is called spangling and comes from the underlying crystalline zinc which to me also looks "toothy."

A thin layer of zinc oxide/carbonate passivates the underlying steel from oxygen, but even if the coating is scratched, the exposed iron will not corrode because adjacent zinc offers up its electrons instead. This basic notion was first conceived by Sir Humphry Davy in the context of protecting copper sheathing on ship's hulls. link  In the days of iron rails, little zinc spikes were hard-wired to rails and served the same purpose. Rail workers only needed to come by periodically and replace the spent zinc anodes and check the wiring. Nowadays, aluminum and magnesium anodes are also used, depending on the application.

Sir Davy and the Royal Navy

Fortunately science, like that nature to which it belongs, is neither limited by time nor by space. It belongs to the world, and is of no country and no age. The more we know, the more we feel our ignorance; the more we feel how much remains unknown...

 ~Sir Humphry Davy, November 30, 1825

Sir Humphry Davy (1778-1829)

Sir Humphry Davy—Byronic scientist extraordinaire and mentor to Michael Faraday, scientist plus extraordinaire—once proposed a clever solution to a problem vexing the Royal Navy. But his idea led to unintended consequences. Davy was publicly embarrassed by the Admiralty, and his career never recovered and set the stage for Faraday's rise to the epitome of British science. Sadly, Davy's health also faltered (a possible consequence of chlorine and fluorine gas inhalation). Here's the fascinating story:

 ... at the beginning of 1823...the Navy Board (which provided the Royal Navy's civilian administration) approached Davy about the possibility of protecting the copper sheeting of warships from the corrosive effects of seawater. The naval budget had been reduced by 71.4% since the end of the war of 1815, and hence the Navy Board was seeking to lower expenditures. If the frequency with which ships needed to be dry docked to replace their corroded copper could be reduced, then significant savings would be made.

During 1823, the Navy Board provided Davy with information about copper corrosion and following his return from holiday at the end of October, he began investigating the problem. By mid-January 1824, he concluded that there existed an electrical reaction between the copper and the oxygenated seawater (no corrosion occurred when oxygen was not present) which allowed the formation of various copper salts. Thus he reasoned, that if the electrical polarity between the copper and the seawater was reversed, the corrosion would cease. In his Elements of Chemical Philosophy (1812), he had ranked the electro-chemical reactivities of various metals. Zinc was much more electro-positive than copper-which suggested that a relatively small amount attached to the copper would prevent the corrosion.*

...the Admiralty ordered that practical tests should be carried out on three warships moored in Portsmouth Dockyard. Starting in mid-February 1824. Davy's "protectors" as they were called were attached to their copper, the state of which was monitored in the ensuing months. Faraday, who undertook most of the follow-up experiments, visited Portsmouth once. At the end of April, satisfied that the tests were successful, the Navy Board drafted an order that the entire fleet be fitted with the protectors...and the fitting programme was undertaken during the remainder of the year and into 1825. However...problems began to appear, and by the summer it was clear that the Navy faced a major disaster. Ships returning from the West and East Indies were found to have their bottoms, though preserved, fouled with seaweeds, barnacles, and suchlike. Because of the protectors, no longer were the poisonous salts produced by the corroding copper being released into the water to kill the source of the fouling. Davy...had tried by varying the ratios of protectors to copper to prevent it, but such was the rush and inadequacy of the Portsmouth trials, that...the Admiralty ordered the removal of the protectors.

Then there followed the political task of allocating the blame for the disaster. The Navy Board had protected itself by doing only what the Admiralty ordered. Hence in the eyes of the Admiralty...Davy was to blame. This failure doubtless contributed to Davy's ill health and premature resignation as President of the Royal Society on 6 November 1827.

~Frank A.J.L. James Michael Faraday: A Very Short Introduction, Oxford University Press (2010)

Two years later, Davy was dead at the age of 51.

Sir Humphry Davy Also Bleached The French

Muriatic Acid: a synonym for hydrochloric acid. Muriatic † pert. to brine; ‘marine’ (acid), hydrochloric. XVII. — L. muriāticus, f. muria brine (the acid being obtained by heating salt with sulfuric acid).

Chemistry is fraught with confusing synonyms and antiquated terms. "Muriatic acid" is such an example. The acid itself was known to medieval alchemists who concocted it from vitriol and sal ammoniac (the salt of Ammon). They discovered that it (in combination with lesser parts of nitric acid) would dissolve gold--whence the fanciful name aqua regia.

We owe the modern name hydrochloric acid to Sir Humphry Davy, who also dealt a great blow to French scientific pride. Davy (1778-1829) dealt with the nature and definition of acids which was the cutting edge of chemical knowledge in his day:

French chemists, following Lavoisier, argued that all acids must contain oxygen (which means 'acid producer') and that therefore muriatic acid contained oxygen. Davy showed that muriatic acid gas was a chemical element which he named chlorine and that muriatic acid was a compound of hydrogen and chlorine (hydrochloric acid, HCl) containing no oxygen.

--Frank A.J.L. James Michael Faraday: A Very Short Introduction, Oxford University Press (2010)

Davy gave the name chlorine to the element because of its color:

As the new compound in its purest form is possessed of a bright yellow green colour, it may be expedient to designate it by a name expressive of this circumstance, and its relation to oxymuriatic gas. As I have named that elastic fluid Chlorine, so I venture to propose for this substance the name Euchlorine, or Euchloric gas from ευ and χλωρος. The point of Nomenclature I am not, however, inclined to dwell upon. I shall be content to adopt any name that may be considered as most appropriate by the able chemical philosophers attached to this Society. link 

Lithium (1/3)

The other day at Costco I noticed one of those bilingual signs: “Batteries/Piles.” The Spanish word pila echoes the historical origin of batteries (cf. the obvious name from the photo above). In the year 1800, Alessandro Volta (the guy the Chevy Volt is indirectly named after) invented what became known as the voltaic pile, thus enabling the first systematic studies of how electricity interacts with matter.

Sir Humphry Davy seized upon the idea of electrolyzing dry molten salts and metal oxides with voltaic pile electrodes (the two wire thingies in the photo above). Davy prepared several elements for the first time, producing blobs of highly reactive metals at one wire when he electrolyzed molten natrium and kalium salts. Davy gave the new metals “ium” names derived from their material origins: sodium from caustic soda and potassium from potash. Davy was so persuasive, and his demonstrations so dramatic, that he successfully renamed the elements: natrium became sodium and kalium became potassium. Today, only the Germans use the older names, though they do survive in the modern chemical symbols, Na and K.

Lithium was discovered in mineral ore samples in 1817. Its discover, J. A. Arfvedson, thought it appropriate to name the new element after the Greek word lithos = stone [cf. lithosphere], to distinguish it from the chemically similar elements sodium and potassium, both of which had been first found in sea and land plant ashes. A year later Sir Humphry prep'd lithium metal by electrolyzing molten lithium oxide.

Metallic lithium is the lightest of metals, so light that it floats on oil; it would float on water too if it didn’t spontaneously react and produce combustible hydrogen gas: see link. The brilliant red color briefly seen in that video comes from gaseous lithium atoms “cooling” in the outer reaches of the flame by giving up red photons. Today lithium salts are used in pyrotechnics to give brilliant red colors.

Lithium sits near the extreme upper left corner of the Periodic Table, directly beneath hydrogen.* Lithium follows helium in sequential order, but the two elements couldn’t be more different. Explaining why helium and the other noble gases are so chemically stable requires a plunge into quantum mechanics (at least at the level of an elementary text book); suffice it to say that when moving from helium to lithium, the third electron that elemental lithium requires cannot share the same space as its first two electrons and must be held at a greater distance, i.e., be more weakly bound. The third electron is said to be a valence electron. The concept of valency comes from a Latin word meaning "combining power of an element" and refers to an element’s ability to gain, lose or share electrons.

Lithium doffs its third electron with ease, becoming lithium ion (Li⁺) and by so doing regains the magic electronic configuration of helium. By analogy, Na⁺ has the magic noble gas configuration of neon, and K⁺ has the noble gas configuration of argon.

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*Hydrogen is not an alkali metal however it is classed in Group I, the western edge of the Periodic Table. Hydrogen shares some chemical properties with lithium and the other alkali metals, namely the oxidation state of +1. On the other hand, hydrogen also can also be a hydride, having pseudo-halide properties.