For about the past two centuries, the chemistry of solutions has been the chemistry of aqueous solutions. Only in recent years have different environments, ammonia in particular, been extensively studied. In the last forty years, however, the industrial relevance of germanium and silicon electronic devices has provoked interest in solid solutions of almost all elements in these semiconductors. In this article, concepts taken from the physics of semiconductors and the chemistry of solutions will be brought together in an attempt at founding a new chapter of physical chemistry—solution chemistry in silicon.