Known Since Antiquity

Anthraquinone [84-65-1] has yet to be found in nature, although some of its substitution products have been known since antiquity (alizarin, kermes, cochineal, and lac dye). Of all the quinones found naturally, those derived from anthraquinone far exceed all others. Many of these are found in molds (2). 

The conjugated chromophore (color-causing) system can be extended by electron-donor groups such as —NH2 and —OH and by electron-acceptor groups such as —NO2 and —COOH, often used at opposite ends of the molecule. An example is the aromatic compound alizarin [72-48-0], also known since antiquity as the ted dye madder. 

The addition of oxides to ceramic bodies and to glasses to produce color has been known since antiquity (2). The use of iron and copper oxides predates recorded history. Cobalt was introduced into Chinese porcelain about 700 AD. Chromium compounds have been used since 1800 AD. 

Compounds closely related to the sulfonamide antibiotics proved to be the first drugs effective against Mycobacterium leprae, the causative agent of the disease known since antiquity, leprosy. These drugs are at least partly responsible for the decline of I hose horror spots, the leper colonies. 

Tin and lead are obtained very easily from their ores and have been known since antiquity. Tin occurs chiefly as the mineral cassiterite, SnOz, and is obtained from it by reduction with carbon at 1200°C ... 

Aluminum is unique among the main group metals. All other p block metals have filled valence d orbitals. As a consequence, these metals have much in common with their transition metal neighbors. They tend to be soft Lewis bases. Aluminum, on the other hand, lacks a filled d orbital set and is a hard Lewis acid that has more in common with its nearest neighbor, magnesium. Highly reactive, aluminum is found naturally in the +3 oxidation state and is difficult to reduce to the pure metal. Thus, although tin and lead have been known since antiquity, aluminum was not discovered until 1825 and did not become a common commodity until more than 60 years later. 

It also has been known since antiquity that aqueous extracts of the ash... 

The jelly-forming power of pectin has been known since antiquity. The factors responsible for jelly formation have been combined in a mathematical formula (11) ... 

Borax, another fluxing material, is a mineral (composed of hydrated borate of sodium), which has also been known since antiquity. There seems to be no evidence however that it was used in the past as a flux it served mainly as a mordant, for dyeing textiles. Until the eighteenth century borax was apparently procured only from a lake in Tibet, whence it was exported to the Near East and Europe. Sources of borax in Asia Minor and in Tuscany, Italy, were discovered only in much later times. 

The use of dyes seems to have began over 10 millennia ago, when dyes of vegetable origin were apparently applied to the skin simply for amusement, for ritual purposes, or to identify or differentiate status or social group. All the dyes used in the past and up to the nineteenth century, when artificial dyes were first synthesized, were of natural origin most were extracted from plants, some from animals (Verhecken 2005). Common dyes well known since antiquity are listed in Table 92 (Kirby 1988 Celoria 1971). 

The transition metals iron and copper have been known since antiquity and have played an important role in the development of civilization. Iron, the main constituent of steel, is still important as a structural material. Worldwide production of steel amounts to some 800 million tons per year. In newer technologies, other transition elements are useful. For example, the strong, lightweight metal titanium is a major component in modern jet aircraft. Transition metals are also used as heterogeneous catalysts in automobile catalytic converters and in the industrial synthesis of essential chemicals such as sulfuric acid, nitric acid, and ammonia. 

Prior to the development of the chemical industry in the late nineteenth and early twentieth centuries, only substances from natural sources were available for treating our diseases, dying our clothes, cleansing and perfuming our bodies, and so forth. Extracts of the opium poppy, for instance, have been used since the seventeenth century for the relief of pain. The prized purple dye called Tyrian purple, obtained from a Middle Eastern mollusk, has been known since antiquity. Oils distilled from bergamot, sweet bay, rose, and lavender, have been employed for centuries in making perfume. 

The adverse effects of stress and depression, the effects of bereavement, unemployment and social isolation on mental and physical health have been known since antiquity. Aristotle advised physicians, "Just as you ought not to attempt to cure eyes without head or head without body, so you should not treat body without soul." One of the fathers of modem medicine put it more scientifically in the 19th century when he recommended that when attempting to predict health outcomes from tuberculosis in patients, it is just as important to know what is going on in a man s head as it is in his chest. 

Lead (Pb) The chemical symbol for lead comes from the Latin plumbum, which also gives us the word plumber. It is highly malleable and ductile and has been known since antiquity. One ancient, albeit poorly chosen, application of lead was to fashion water pipes, and, hence the connection to the word plumber. 

Products obtained by melting two or more metals together and allowing the resulting mixture to cool and solidify are called alloys. By far the great majority of the metallic objects encountered in everyday use consist of alloys rather than pure metals. In fact, iron and aluminum are the only metals used extensively in relatively pure form. Some of the more common alloys such as bronze have been known since antiquity and have contributed markedly to the development of modem civilization. Since alloys are of greater practical importance than pure metals, you should acquire at least some familiarity with the nature, properties, and uses of alloys. 

Compounds of the alkaline earth metals occur widely in nature, and some of them have been known since antiquity. Calcium carbonate, of which limestone is one form, has been used as a building material since the Stone Age and as a source of lime (CaO) for... 

Arsenic is found primarily as sulfides in orpiment, As2S3, realgar, AS4S4, and arsenopyrite, FeAsS, but it also occurs as arsenolite, As406. Arsenic compounds have been known since antiquity, and orpiment, which is yellow, was probably used as a yellow pigment. 

Phosphorus has many allotropes. The most common of these is white phosphorus, which exists in two modifications, a-P4 (cubic) and p-P4 (hexagonal). Condensation of phosphorus from the gas or liquid phases (both of which contain tetrahedral P4 molecules) gives primarily the a form, which slowly converts to the P form at temperatures above —76.9°C. During slow air oxidation, a-P4 emits a yellow-green light, an example of phosphorescence that has been known since antiquity (and is the source of the name of this element) to slow such oxidation, white phosphorus is commonly stored under water. White phosphorus was once used in matches however, its extremely high toxicity has led to its replacement by other materials, especially P4S3 and red phosphorus, which are much less toxic. 

Sulfur itself has been known since antiquity and, because of its associations with volcanic eruptions, was referred to in the past as brimstone (burning stone). In the third century, Chinese alchemists used a mixture of sulfur with saltpetre (KN03) as a primitive gunpowder. Elemental sulfur is widely distributed in nature and also as compounds such as hydrogen sulfide, sulfur dioxide, sulfates, e.g. those of calcium and magnesium, and sulfide ores. 

Asthma has been known since antiquity, yet it is a disease that still defies precise definition. The word asthma is of Greek origin and means panting. More than 2000 years ago, Hippocrates used the word asthma to describe episodic shortness of breath however, the first detailed clinical description of the asthmatic patient was made by Are-taeus in the second century. An expert panel of the National Institutes of Health, the National Asthma Education and Prevention Program (NAEPP), has provided the following working definition of asthma ... 

The adverse effects of exposure to lead on human health have been known since antiquity, but it was not until the last century that lead poisoning was recognized to be a serious health threat to children (3, 431). Children are not only more likely to put things in their mouths and hence to ingest lead, but also experience symptoms of lead poisoning at much lower BLLs than do adults (29,... 

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