Principle (chemistry)

In modern chemistry, principles are the constituents of a substance, specifically those that produce a certain quality or effect in the substance, such as a bitter principle, which is any one of the numerous compounds having a bitter taste.

The idea of chemical principles developed out of the classical elements. Paracelsus identified the tria prima as principles in his approach to medicine.

Georg Ernst Stahl published Philosophical Principles of Universal Chemistry in 1730 as an early effort to distinguish between mixtures and compounds. He writes, "the simple are Principles, or the first material causes of Mixts;..." To define a Principle, he wrote

Stahl recounts theories of chemical principles according to Helmont and J. J. Becher. He says Helmont took Water to be the "first and only material Principle of all things." According to Becher, Water and Earth are principles, where Earth is distinguished into three kinds. Stahl also ascribes to Earth the "principle of rest and aggregation."

Historians have described how early analysts used Principles to classify substances:

Guillaume-Francois Rouelle "attributed two functions to principles: that of forming mixts and that of being an agent or instrument of chemical principles."

In his book The Sceptical Chymist of 1661, Robert Boyle criticized the traditional understanding of the composition of materials and initiated the modern understanding of chemical elements.

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