The article describes the molecular structure and fundamental physical properties of erythritol tetranitrate (ETN). Although ETN is simple nitrate ester this explosive is described in the literature relatively briefly. The molecular structure of ETN was characterized by single-crystal X-ray diffraction. The structure of the ETN molecule is composed of the central carbohydrate chain and two pairs of facing coplanar ONO2 groups. The crystal density of ETN is 1.827gcm(-3). It is a non-hygroscopic compound. Solubility in water was determined in a temperature range from 5 degrees C to 80 degrees C. ETN is slightly soluble in water; solubility at 20 degrees C is on the same level as that of PETN.