“…Here we address the changing relationships between structural correlations and thermodynamics that underlie the transformation of a simple liquid into a complex, tetrahedral liquid dominated by triplet correlations, driven by a systematic variation of the degree of anisotropy of the interparticle interactions. Tetrahedral fluids are among the simplest of complex fluids and include a number of important systems, such as water, ionic melts (SiO 2 ,BeF 2 ), covalently bonded liquids (C, Si), metalloids (Ge, Sn), and dispersions of patchy colloids [4][5][6][7][8][9][10][11][12][13]. They show a density-driven shift from four-coordinate, local order at low densities to random, close-packing arrangements at high densities.…”