Carbon was known in prehistory in the form of soot; while charcoal was made in Roman times (by heating wood while exclude air) and diamonds were known as early as 2500 BC in China. In 1772, Antoine Lavoisier (Figure 1) showed that diamonds were a form of carbon, when he burned samples of carbon and diamond and showed that both formed the same amount of carbon dioxide per gram of material. Carl Scheele (Figure 2) showed that graphite was a form of carbon rather a form of lead.

Figure 1: French chemist and biologist Antoine-Laurent de Lavoisier (1743 – 1794).

Figure 2: German-Swedish pharmaceutical chemist Carl Wilhelm Scheele (1742 - 1786). Author Isaac Asimov has called him "hard-luck Scheele" because he made a number of chemical discoveries before others who are generally given the credit.

A new allotrope of carbon, fullerene, was discovered in 1985 by Robert Curl, Harry Kroto, and Richard Smalley (Figure 3) who subsequently shared the Nobel Prize in Chemistry in 1996. Fullerenes have been reveled to include nanostructured forms such as buckyballs and nanotubes. The renewed interest in new forms lead to the discovery of further exotic allotropes, including glassy carbon, and the realization that amorphous carbon is not amorphous.

Figure 3: Rice University chemists Richard E. Smalley (1943 - 2005) and Robert F. Curl (1933 - ).

Silicon was first identified by Antoine Lavoisier (Figure 1) in 1787 as a component of flints, and was later mistaken by Humphry Davy (Figure 4) for a compound rather than an element. In 1824, Berzelius (Figure 5) prepared amorphous silicon by the reaction of potassium with silicon tetrafluoride, Equation 1

(1)

Figure 4: British chemist and inventor Sir Humphry Davy FRS (1778 - 1829).

Figure 5: Swedish chemist Jöns Jacob Berzelius (1779 – 1848).

In 1869 Dmitri Mendeleev (Figure 6) predicted the existence of several unknown elements, including ekasilicon (Es) between silicon and tin.

Figure 6: Russian chemist and inventor Dmitri Ivanovich Mendeleev (1834 – 1907).

In 1885 a new mineral (named argyrodite because of its high silver content) was found in a mine near Freiberg, Saxony. Clemens Winkler (Figure 7) isolated Mendeleev’s missing element. He originally was going to name neptunium because like this element, because like ekasilicon, the planet Neptune had been preceded by mathematical prediction of its existence. However, the name neptunium had already been given to an element and so Winkler named the new metal germanium in honor of his fatherland.

Figure 7: German chemist Clemens Alexander Winkler (1838 –1904).

Winkler was able to isolate sufficient germanium from 500 kg of ore to determine a number properties, including an atomic weight of 72.32 g/mol by analyzing pure germanium tetrachloride (GeCl₄). Winkler prepared several new compounds of germanium, including the fluorides, chlorides, sulfides, germanium dioxide, and tetraethylgermane (Ge(C₂H₅)₄). The physical data from these compounds, corresponded with Mendeleev's predictions (Table 2).

Tin is one of the earliest metals known. When the addition of about 5% tim to molten copper produced an alloy (bronze) that was easier to work and much harder than copper, it revolutionized civilization. The widespread use of bronze to make tools and weapons became part of what archaeologists call the Bronze Age. The Bronze Age arrived in Egypt, Mesopotamia and the Indus Valley culture by around 3000 BC.

Lead has been commonly used for thousands of years because of its ease of extraction, and its ease of smelting. Lead beads dating back to 6400 BC have been found in Çatalhöyük in modern-day Turkey, while lead was used during the Bronze Age.

Carbon dating is a process whereby the age of a material that contains carbon can be determined by comparing the decay rate of that material with that of living material.

Carbon-14 has a half life (t_1/2) of 5.73 x 10³ years for its decay to nitrogen-14 by the loss of a β particle, Equation 2.

(2)

The rate of radioactive decay can be expressed as a rate constant (k):

(3)

For carbon-14, using Equation 3,

(4)

In 1947 samples of the Dead Sea Scrolls were analyzed by carbon dating. It was found that the carbon-14 present had an activity of d/min.g (where d = disintegration); by contrast in living material the activity is 14 d/min.g. Thus,

(5)

(6)

From the measurement performed in 1947 the Dead Sea Scrolls were determined to be 2000 years old giving them a date of 53 BC, and confirming their authenticity. This discovery is in contrast to the carbon dating results for the Turin Shroud that was supposed to have wrapped Jesus’ body. Carbon dating has shown that the cloth was made between 1260 and 1390 AD. Thus, the Turin Shroud is clearly a fake having been made over a thousand years after its supposed manufacture.

The elements carbon through tin (in its α form) all exist in diamond cubic structure (Figure 10a), while lead crystallizes in a cubic close packed structure (Figure 10b). As expected the lattice parameter (a) increases with increased atomic radius (Table 6). The switch from diamond cubic to close packed cubic may be rationalized by the relative atomic sizes. The diamond cubic structure comprises of two interpenetrating cubic close packed lattices. As the atomic size increases large interstitial vacancies would result, resulting in an unfavorable low-density structure.

Figure 10: Unit cell structure of (a) the diamond cubic lattice showing the two interpenetrating face-centered cubic lattices, and (b) the cell of cubic close packed structure for comparison.