Aurora Clark, an associate professor of chemistry at Washington State University, has adapted Google’s PageRank software to determine the way molecules are shaped and organised.

Hydrogen bonds between different water molecules are in fact similar to the hyperlinks between different websites: in the same way that some hyperlinks are worth more than others, some molecular links are stronger than others.

Google’s PageRank algorithm was developed at Stanford University by Larry Page and Sergey Brin. It essentially decides how important a website is, taking the number and importance of website links to it into account. Clark adapted Page and Brin’s idea to build “moleculaRnetworks”, which substitutes websites and hyperlinks for molecular shapes and chemical reactions. Water molecules are ranked on the basis of how many hydrogen bonds they make and how many of these bonds nearby molecules have. This system can then quickly characterise the interactions of millions of molecules, which is very useful in predicting how various chemicals will react with one another, saving the expense, logistics and danger of lab experiments. Predicting chemical reactivity will help in drug design, to understand better how different proteins lead to different diseases, in the analysis of radioactive pollutants and much more.