Silicon is an element that appeals to the imagination. In, among other things, the science fiction series Doctor Who in Star Trek alien life forms exist that are based on silicon, instead of carbon like life on Earth.
Science fiction writers choose silicon in their stories because it is right below carbon on the periodic table. Elements that share a column often have similar properties. For example, silicon and carbon atoms both have four free electrons in their outer shells, allowing them to form a wide range of bonds, which is necessary for the complex chemistry of life.
Carbon can form more than a million bonds
In addition, silicon is ubiquitous. It is the eighth most common element in the universe. More than a quarter of the mass of the earth’s crust consists of element 14. You will find silicon mainly in the form of silicon dioxide (silica), which sand and stones such as quartz, flint and amethyst consist of.
Although life on Earth is not based on it, there are some life forms that make use of this element. For example, there are sponge animals that build their skeletons with silicon dioxide and the exoskeleton consists of diatoms, which are single-celled algae.
For humans, silicon is one of the most useful elements. This started with the discovery that with broken pieces of flint you can not only make fire – and with it heat and light – but also sharp tools, such as hand axes.
Later, humans developed building materials such as cement and bricks, with silicon dioxide as the main ingredient. This was followed by an even greater discovery: if you melt silica, glass is created. And with it windows, glasses and telescopes.
Despite its many applications, silicon was only discovered in 1824 by the Swedish chemist Jöns Jacob Berzelius. It turned out to be incredibly difficult to pull the silicon loose from the atoms to which it is connected, such as oxygen. This only works at high temperatures.
That extremely strong bond between element 14 and oxygen is one of the reasons that it is unlikely that silicon-based life forms really exist. In addition, other silicon compounds are too weak and do not mix well with the elixir of life water. In conditions that we see as favorable for life, silicon life forms seem to have little chance. (We use the biological definition of life.)
But we haven’t yet talked about the technological application of silicon that is so famous that a region in California is named after it: Silicon Valley. By adding a tiny amount of other elements to ultrapure silicon, you can produce a semiconductor with exactly the desired electrical properties for computers and other (micro)electronics. In addition, the photoelectric properties of silicon make it a suitable material for solar cells.
With the rise of artificial intelligence, computers are increasingly behaving like humans. You could say that researchers are aiming for a silicon-based form of intelligence, which you might even call a form of life.