Reproducing the experimentally observed shortening of chemical bonds under pressure is one of the key tasks of high-pressure simulation techniques. When a novel method is being published, pressuredependent interatomic distances typically belong to the first quantities to be reported. A relation between pressure and interatomic distances in inorganic crystals has already been established two decades ago using a mathematical model that takes into account the force exerted on the atoms involved in a chemical bond upon compression. The capability of XP-PCM in relating pressure, equilibrium geometries and electron density in chains of hydrogen atoms has been demonstrated as well. GOSTSHYP allows the calculation of the pressure-vs-volume curves of substances, e.g., fullerenes, and, in principle, also the pressure-dependent volume of the electron clouds between atoms involved in a chemical bond.