Overheard at Lem's:
Sixty Grit said...
...
III/V, baby - those were the groups we used. Si, indium, aluminum, gallium. those were the ones I had direct experience with.
Carbon, silicon, and germanium align vertically in the Periodic Table like a stack of mid-verse rhymes. I say "mid-verse" because they're not at the end of the periodic verses -- the noble gases are. Further below, the rhyme continues with the heavy metals tin and lead, making a vertical pentad of elements.
Carbon, tin, and lead were long-known but silicon eluded discovery until the early 19th-century. This seems astonishing because silicon is the second most abundant element in the earth's crust behind oxygen. The simple combination of silicon and oxygen, SiO
2, is the inorganic analog of CO
2 and is otherwise known as sand or, when pure, quartz. Elemental silicon was long suspected and early 19th century chemists were convinced that some new element must be present as an oxide in silica -- the problem was finding something to free it from oxygen. Voltaic piles -- which had then recently helped reveal metallic sodium and potassium -- were too weak.
Berzellius used a two-step process, first treating quartz with HF to generate SiF
4 and then treating the SiF
4 with potassium metal. Recently discovered potassium metal was needed. The Germans still call silicon
Silizium, giving it the metallic suffix
-ium.
Another German (a very bad one) developed a carbo-centric Periodic Table which contains more chemical subtlety than I can master: