Tomás Batuecas Marugán (1893–1972) was a Spanish chemist, most notable for his work on atomic weights of the elements.

[1] He graduated with honors from the Faculty of Sciences at the University of Salamanca in 1913 and in the same year began doctoral studies in Madrid under Blas Cabrera Felipe.

In 1916, Batuecas studied in the University of Geneva with Philippe A. Guye where he was interested in density and compressibility of real gases.

The work on atomic weights started in Geneva in 1916 with Guye, and was focused to evaluate Daniel Berthelot’s method of limiting densities for real gases.

The most notable contribution of Batuecas in this field is perhaps his role in the adoption of the international scale of atomic weights based on the carbon-12 nuclide.