Precipitation is an important unit operation to produce solid products in the chemical and pharmaceutical industry. Basically, precipitations are mixing processes of two or more educts. The mixed educts react to an insoluble product which immediately falls out by forming solid particles. This thesis contributes to the state of the art in precipitation research by proposing a novel and comprehensive theory of similitude for mixing-influenced precipitations. Key element of this theory is a thorough dimensional analysis, which is exemplarily conducted for barium sulfate precipitation from aqueous educt solutions. The resulting generic similitude function is applied to investigate three different fields: The impact of the flow regime on the particle size, scale-up of technical precipitation reactors and material-independent forms of data presentation. The significant results gained in all of these fields demonstrate the power of dimensional analysis as a method, but also the risk of data misinterpretation becoming relevant if its underlying key principles are violated unintentionally.