Chemical Elements

"Iodine was discovered by Courtois of Paris in 1812 in the mother-liquors collected in the process of manufacturing the sodium salts from kelp or burnt sea-weeds. The name is derived from a Greek word meaning "violet" in allusion to the colour of the vapour of iodine. Its elementary character was established by Gay-Lussac in 1815."

"Speaking broadly... we understand by the Atomicity of a chemical element its power of combining with other elements in equivalent proportions; by its Valency or quantivalence, the difference between that element and other elements in their respective powers of combining with hydrogen as a standard. Thus... Hydrogen, chlorine, bromine, iodine, and fluorine combine with hydrogen atom for atom and are termed Monovalent elements or Monads."

"In developing his ideas of nuclei which were used as a basis of classification in Gmelin's large Handbook of Chemistry [Handbuch der Chemie], as well as in his own Chemical Method, and in his theory of types, he introduced to science the words "anhydride," "amide," "imide," "amidic acid," and others. His Theory of Nuclei was originally mentioned in his Inaugural Dissertation at the Faculté des Sciences at Paris in 1837, but it must not be forgotten that these doctrines are also associated with the name of Gerhardt, who has a share in the honour of their conception and introduction. The Nucleus Theory amounted to this:—The molecules of organic bodies, he said, are either nuclei, or compounds of nuclei, with other substances placed outside them. These nuclei are groups of carbon atoms united with other elements, and are either (1) fundamental nuclei, consisting of carbon and hydrogen only, or (2) derivative nuclei, derived from the fundamental nuclei by substitution. The bodies substituted are generally chlorine, bromine, iodine, oxygen, or nitrogen, but compound bodies, acting as radicles, may be in like manner substituted for hydrogen and enter into the nucleus... In constructing his nuclei and comparing them to prisms, he abandoned the dualistic system, and viewed the compound as a single unitary whole like a crystal. Although the Nucleus Theory has not survived, it laid the foundation of the theory of types which we still use."

"Curious relations, triads and octaves, were discovered to exist among the atomic weights of substances possessing similar physical characters and chemical properties. Chlorine, iodine, and bromine formed such a triad. Adding the atomic weights of chlorine and iodine, 35 and 125, the sum is 160. The mean or half, therefore, is 80, which is the atomic weight of bromine. These three substances are strictly analogous in their modes of combination, their salts are isomorphous, and with the increase in their atomic weight there is a uniform modification of their properties—chlorine is a green gas, bromine a very volatile red liquid, and iodine a slate-coloured solid, volatilised only by heat. Chlorine is the most active chemically, and can expel the others, bromine is next, and iodine is least active. Chloride of silver is easily soluble in ammonia, the bromide soluble with difficulty, and the iodide quite insoluble."

"Meyer published along with [Paul] Jacobson a "Text book of Organic Chemistry" [Lehrbuch der Organischen Chemie], which was not finished; also, either alone or in conjunction with his pupils, upwards of 300 memoirs and papers... His researches [included]...Di- and tri-bromobenzene, in work on which he gained further evidence in support of his view that in the case of the chlorine, bromine, iodine, and nitroxyl (NO2) derivatives of aromatic amines, obtained by the direct substitution of an element, it is always the hydrogen contiguous to the NH2 group that is replaced."

"Never have experiments been conducted with greater care, caution, and exactitude than those of Stas. It is said that the greatest variation between his many individual determinations of the atomic weight of the same element was from .005 to .01. ...Some illustrations may be given of his care in purifying materials. He purified iodine either (1) by dissolving it to saturation in an aqueous solution of potassium iodide, precipitating it with an excess of water, rather less than was sufficient to throw down the full amount possible, washing, distilling with steam, and drying under a bell-glass beside calcium nitrate (the only salt which was found not to affect the purity of iodine); or (2) by acting with solution of ammonia on the iodine to be treated, thus forming nitrogen iodide, or diodamine, as he considered it, decomposing the violently explosive body by heating with excess of water to 60° or 65° Centigrade, and distilling and drying as before. By this latter method he treated some 10 kilogrammes of iodine in lots of 500 grains at a time."

"Berthollet's conclusion that chlorine is oxymuriatic acid was universally accepted until Gay-Lussac and Thénard in 1809 endeavoured to decompose the gas and failed. They concluded that it contained water because it yielded water when passed over litharge. Their researches read to the Institute in 1809 led Davy to investigate muriatic acid (hydrochloric acid) gas, which in 1808 he had shown to be decomposed by potassium, with evolution of hydrogen. In 1810 he proved that chlorine is an element, and that muriatic acid gas is a compound of chlorine and hydrogen. He thus overturned the oxygen-acid theory, and demonstrated that muriates are compounds of metals with chlorine. He pointed to the fact that some acids, such as sulphuretted hydrogen, contain no oxygen, and argued that muriatic acid gas was one of these, chlorine in it taking the place of oxygen. ...The conclusions of Davy were at first doubted, but when iodine and bromine were also discovered, Gay-Lussac and his followers adopted Davy's views. The latter worked out fluorine, and proved that hydrofluoric acid (HF) contains no oxygen. Berzelius also opposed Davy until the discovery of iodine, but embraced the latter's opinion in 1820."

"A French saltpetre manufacturer, Courtois, in 1811 discovered a strange substance in the soda obtained from sea plants; he told his discovery to Clément, who showed the body in question to Davy. Davy soon demonstrated its elementary nature and Gay Lussac, after a complete investigation of iodine, as he called it, and its compounds, succeeded in showing its marked likeness to chlorine."

"In 1812 [Humphry Davy's] Elements of Chemical Philosophy was published, and next year he travelled on the Continent. During this journey, while in Paris, he examined iodine, and declared it to be an element."

"Gay-Lussac was one of the most brilliant of the French chemists, and spent his whole life in research. His principal subjects of investigation [included]... Iodine and its compounds. ...Gay-Lussac's Memoir on Iodine appeared in 1814. This substance had been discovered three years previously by Bernard Courtois. Davy, in respect of its analogy to chlorine, had declared it to be an elementary body. Gay Lussac, doubting this conclusion, made a careful investigation of iodine, and described its peculiar properties and those of its compounds. This substance was shortly afterwards recognised as an element."

"From this time oxygen began to be conventionally spoken of as the "supporter of combustion," and substances which burn in it were called "combustibles." Yet this manner of speaking is purely conventional, and is due to the abundance of oxygen in the atmosphere. Combustion is merely a special case, in which the heat of combination is exceptionally augmented. After the discovery of chlorine, bromine, and iodine, and when bodies were found to burn in the vapours of these substances, as well as in oxygen, the term "supporter of combustion" was extended to every substance capable of forming vapour in which others could burn; but as the same substance may act at one time as a "supporter," and at another time as a "combustible," the distinction has gradually become obsolete."

"Laurent, in 1837, striving after the real truth of substitution, had pictured the organic molecule as a prism, the angles of which were occupied by carbon atoms, the centres of its edges by hydrogen atoms, or failing these by chlorine, bromine, or iodine atoms."

"The table of Mendeleeff was changed but little for thirty years. Its anomalies, as the omission of hydrogen and the rejection of the atomic weight as the deciding factor in such cases as cobalt and nickel, tellurium and iodine, etc., were recognized; but greater knowledge was needed before these could be explained or the underlying law grasped."

"The first numerical regularities observed between the atomic weights were the triads of Döbereiner. This chemist seems to have observed first that the combining weight of strontium was the arithmetical mean of those of calcium and barium. A like regularity was noted with regard to certain physical properties of these elements and some of their compounds. This led him for a while to question the independent existence of strontium. Several similar triads were discovered among the other elements as lithium, sodium, and potassium; chlorine, bromine, and iodine; sulphur, selenium, and tellurium. He was careful not to let this grouping depend upon the atomic weights alone but insisted that only elements exhibiting decided analogies of properties should be considered together. This idea was taken up by other chemists, notably by Gmelin in his Handbook, and many analogies and groups were sought for. In 1857 [Ernst] Lennsen returned to this grouping, endeavoring to force all the elements into some twenty groups. Then Odling sought to build upon them an elaborate system of the elements which he called the Natural System. Such groupings were often forced, and failures. The science was not far enough advanced to enable one to understand the real meaning of these regularities."

"Dumas devised an accurate and excellent method for determining the specific gravities, or densities, of gases which could be used at high temperatures, thus enabling him to experiment upon the vapor densities of iodine, phosphorus, sulphur, mercury, etc. His results, instead of confirming, tended rather to disprove the law of volumes. The trouble lay in the complex nature of the molecules experimented upon, but of course this was unknown to Dumas. He finally declared that even in the case of the simple gases like volumes did not contain equal numbers of chemical atoms. ...The atomic weights determined by him with the greatest care were those of silver, potassium, sodium, lithium, lead, chlorine, bromine, iodine, sulphur, and nitrogen."

"The Incas labored long in the Peruvian mercury mines without knowing what quicksilver was, seeking only cinnabar, or vermilion to use as war paint."

"As Hermes Psychopompos, he also serves as a guide of souls into the underworld. Under his Roman name of Mercury, Hermes is the prime god of the alchemists who hoped to transform base matter into refined, spiritual gold. Mercury is “quick silver”, the spirit that existed in matter."

"Quicksilver is a useful thing for many purposes. For instance, neither silver nor copper can be gilded properly without it. And when gold has been woven into a garment and the garment becomes worn out with age so that it is no longer respectable to use, the pieces of cloth are put into earthen pots, and burned up over a fire. The ashes are then thrown into water and quicksilver added thereto. This attracts all the bits of gold, and makes them combine with itself. The water is then poured off, and the rest emptied into a cloth and squeezed in the hands, whereupon the quicksilver, being liquid, escapes through the loose texture of the cloth, but the gold, which has been brought together by the squeezing, is found inside in a pure state."

"It is a fluid but does not moisten, and runs about, though it has no feet."

"Mercury was known to the ancient Chinese and Hindus, and has been found in Egyptian tombs dating back to 1500 or 1600 B.C. Dioscorides mentioned its preparation from cinnabar, while Pliny gave a method of purifying it by squeezing it through leather, and stated that it is poisonous. Earle R. Caley has shown by quotations from Aristotle, Theophrastus, Dioscorides, Pliny the Elder, Vitruvius, and the Leyden Papyrus of the third century A.D. that mercury has been known much longer than most persons realize. He states that cinnabar was probably the only mercury compound known to the ancients and that they used it both as a pigment and as a source of the metal. In his "Metallurgic Chemistry," C. E. Gellert (1713-1795) stated that “The only ore of mercury hitherto known is native cinnabar". The most ancient specimen of quicksilver known is probably that which H. Schliemann found in a little cocoanut-shaped in an Egyptian tomb at Kurna dating from the fifteenth or sixteenth century B.C."

"Theophrastus, a disciple of Plato and successor to Aristotle, described quicksilver as a useful substance "obtained from native Cinnabar, rubbed with Vinegar in a brass Mortar with a brass Pestle."

"The factitious cinnabar is from the country a little above Ephesus; it is but in small quantities, and is had only from one place. It is only a sand, shining like scarlet, which they collect, and rub to a very fine powder, in vessels of stone only, and afterwards wash in other vessels of brass, or sometimes of wood: What subsides they go to work on again, rubbing it and washing it as before."

"One Callius, an Athenian, who belonged to the silver mines, invented and taught the making of this artificial Cinnabar. He had carefully got together a great Quantity of this sand, imagining from its shining appearance that it contained gold: But when he had found that it did not, and had had an opportunity, in his trials, admiring the beauty of its colour, he invented and brought into use this preparation of it. And this is no old thing, the invention being only of about ninety years date; Praxibulus being at this time in the Government of Athens."

"In the first century A.D., Dioscorides Pedanios of Anazarbus, Cilicia, gave the following process for preparing metallic mercury: Putting an iron spoon having Cinnabaris in an earthen pot, they cover the cup, darwing it about with clay, then they make a fire under with coals; and ye soot that sticks to ye pot, being scraped off & cooled, becomes Hydrargyrum [mercury]. It is found also in ye place where silver is melted, standing together by drops on ye roofs. And some say that Hydrargyrum is found by itself in ye mines. But it is kept in glassen, or leaden, or tinnen, or silver vessels, for it eats through all other matter, and makes it run out."

"Many do not even know that mercury comes out of cinnabar (tan sha). When told, they still refuse to believe it, saying that cinnabar is red, and how can it produce a white substance? They also say that cinnabar is a stone that stones when heated turn to ashes: and how then can anything else be expected of tan sha?"

"Natural cinnabar consists of much mercury and some sulfur and earth; these three together make a hard body, a very beautiful red color varying in brightness according to the purity of the ore and the place where it is found. It is brought to us from different localities, as from Transylvania and Hungary and from many places in Germany; the handsomest, however, is found in Carinthia."

"The mercury mines of Almaden had been worked for at least 2287 years and that cinnabar from them was sent to ancient Rome in the form of powder or sand. A. de Galvez Canero believed that the Spanish mercury mines have been worked since the third or fourth century B.C. (28)."

"He was surprised to find that the crops, trees, and inhabitants were not injured by the fumes, and that springs near the mine yielded good potable water. The slaves who worked and ate in the mine however suffered severely from mercury poisoning."

"The Spaniards discovered the mercury mines of Huancavelica in 1566-67. The red substance llimpi with which the Indians used to paint their faces was the same as the Castilian . After the mines of Palcas in the territory of Guamanga had been discovered in this way, much of the mercury obtained from them was shipped to Mexico to be used in the refining of silver]]."

"There was very little use or consumption of quicksilver before the beginning of this new Silver age in the world, then they only wasted it in Mercury sublimate, Cinabrio, or Vermillion, and the powders made thereof called Precipitate, which are also called in Spain the powders of Juanes de Vigo, which have been used to such mischievous purposes that the world was said to have too much of them, although in bulk and quantity then they had but little; but since it hath been used to collect the Silver together out of Oar, which is ground small (an invention which the Ancients had scarcely arrived to, and practised it but very little), it is incredible how great a quantity is consumed by the Founders of Metals of this Kingdom: for if the abundance of Silver that hath gone out of this Kingdom hath filled the world with riches and admiration, by it may be estimated the consumption and loss of Quicksilver, which after a most extravagant expense thereof at first, being now by good experience regulated within terms of moderation, is found to be equal in weight to the Silver extracted; and very seldom that the waste is so little."

"The famous mine of Huancavelica is located on Mount Santa Barbara, south of the city of Huancavelica.... The discovery of the great mercury mine is generally attributed to the Indian, Gonzalo Abincopa, or Navincopa; but it certainly occurred long before the year 1567, for even the Incas used cinnabar [llimpi] for their cosmetics, getting it from the mountains of Palcas. The working of the mine on Mt. Santa Barbara, for the crown, did not begin until about the month of September in 1570, the year in which Fernandez de Velasco introduced Mexican amalgamation into Peru."

"Indians living near the old Santa Clara Mission, about fifty miles from the present city of San Francisco, California, used to apply red and yellow pigments from the "Cave of the Red Earth" near there for personal adornment. In 1845 Captain Andres Castillero of the Mexican Army, who had studied chemistry and metallurgy at the College of Mines in Mexico City, discovered near the Santa Clara Mission an ore in which he easily detected metallic mercury. When Don Manuel Herrera of that College of Mines analyzed specimens of this ore he found an average mercury content of 35.5 per cent and reported that some pieces were practically pure cinnabar."

"When gold was discovered near Sutter's Fort, California, in 1848 the operation of the gold mines that were opened up during the "gold rush of '49" was greatly facilitated by the nearby supply of mercury for amalgamation."

"A method for preparing a rather pure mercurous chloride (calomel) was known to Parisian physicians before 1608."

"Tyrocinium Chymicum a "mild sublimate" was made by rubbing corrosive sublimate with as much mercury as could be "killed" or made to combine with it."

"Calomel, corrosive sublimate, and vermilion have been manufactured for centuries at Hankow, China. Chemists of India prepared both chlorides of mercury as early as the twelfth century. A detailed description of the process was given in the thirteenth or fourteenth century . A mixture of common salt, brick dust, alum, Indian aloe, and mercury was heated for three days in a closed earthen pot. The Japanese and Chinese also prepared calomel by similar methods."

"The Freezing of Mercury: Until the middle of the eighteenth century, chemists believed that fluidity was an essential property of mercury. During a blizzard on the twenty-fifth of December, 1759, A. Braune (or Braun) and M. V. Lomonosov of the Academy of Sciences of St. Petersburg thought it would be interesting to see how much farther the temperature could be lowered by artificial means. In the presence of several fellow members of the Academy, they packed a mercury thermometer in a mixture of nitric acid and snow. The mercury fell rapidly and solidified."

"...mercury use, as well as many of its treatment techniques are in fact as ancient as the Pharaohs and the Romans; and while recorded history proves that the Egyptians followed by the Greeks and Romans used mercury for cosmetic and medical preparations over five thousand years ago; we are now taking about ppt level, which mocks the expression “splitting hair”."

"Mercury does not react with most acids, such as dilute sulfuric acid, although s such as concentrated sulfuric acid and nitric acid or aqua regia dissolve it to give sulfate, nitrate, and chloride salts. Like silver, mercury reacts with atmospheric hydrogen sulfide."

"Mercury dissolves many other metals such as gold and silver to form amalgams. Iron is an exception and iron flasks have been traditionally used to transfer mercury."

"Mercury readily combines with aluminum upon contact, to form a mamagam that destroys Aluminium oxide layer which protects metallic aluminum from oxidizing in-depth."

"Mercury minerals in deposits in nature consist mainly of corderiote (Hg3S2CL2), livingstonite (HgSb4S7), montroydite (HgO), terlinguaite (Hg2OCL), HgS, calomel Hg2CL2,coloradoite HgTe, and teimannite HgSe."

"Mercury exists in two oxidation states: mercurous (valence+1) and mercuric (valence+2). Organic compounds of weak reducing activity such as amines, aldehydes, and ketones often break Mercury compounds to compounds of lower oxidation state and metal."

"Isotopes: There are seven stable isotopes of mercury with 202Hg being the most abundant (29.86%). The longest-lived radioistopes are 194Hg with a half-life of 444 years, and 203Hg with a halflife of 46.612 days. Most of the remaining radioisotopes have half-lives that are less than a day."

"The toxicity of mercury is not a recent discovery either. Galen, who died about 200AD wrote about the toxicity of mercurials. As to the therapeutic uses of mercury compounds the “Chemical technology reference” makes this statement: “...in the 13th century, as a result of Arabian influence, such therapeutic uses of mercury were finally recognized by Western Europe. Some of these uses are specially supported by recorded history in Egypt 5000 years ago and, in China and India dating over 4000 years ago."

"Inorganic mercury compounds are formed when mercury combines with elements other than , such as , , or oxygen. Elemental mercury is a form of inorganic mercury."

"Organic compounds of mercury, are known in which mercury is bound directly to oxygen, nitrogen, sulphur. In oxygen-linked compounds, the mercury generally behaves as in inorganic salts. Compounds containing a N-Hg link will be formed if you allow for a reaction of mercuric salts or alkyl and arylmercuri-compounds with amines and amides."

"Atmosphere/air: Air samples are collected when mercury pollution is believed to be present in the atmosphere or . Since mercury concentrations in the atmosphere vary greatly, sampling points must be selected in order to clarify the mercury distribution with consideration given to prevailing winds and the distance from the contamination source."

"Blood: For people who eat large quantities of fish and , the mercury concentration ratio of to (serum) is approximately 10:1, and most mercury contained in the red blood cells is in the form of ; therefore, methylmercury exposure can be evaluated by measuring total mercury in blood. It is believed that 50% of inorganic mercury is present in the plasma and the mercury concentration in the plasma increases in relation to the amount of inorganic mercury accumulated in the kidneys."

"It is the only metal that is a liquid at room temperature and it evaporates, or vaporizes, relatively easily. Mercury can also combine with other metals to make "amalgams", or solutions of metals, and has been used in the extraction of gold because of this property. One of the first metals to be mined, it was found in Egyptian tombs dating back to 1500 B.C. Mercury has been a part of the occult arts and human folklore and has been used in medicine, science and technology for millennia. In the modern world, there are many cultural, commercial and industrial uses for the metal still in practice."