In order to explain the known anomalies in water, some researchers assume that water consists of a mixture of two phases even under ambient conditions.
However, new X-ray spectroscopic analyses at BESSY II, ESRF and Swiss Light Source show that this is not the case. At room temperature and normal pressure, the water molecules form a fluctuating network with an average of 1.74 ± 2.1% donor and acceptor hydrogen bridge bonds per molecule each, allowing tetrahedral coordination between close neighbours.
Water at ambient conditions is the matrix of life and chemistry and behaves anomalously in many of its properties. Since Wilhelm Conrad Röntgen, two distinct separate phases have been argued to coexist in liquid water, competing with the other view of a single-phase liquid in a fluctuating hydrogen bonding network – the continuous distribution model. Over time, X-ray spectroscopic methods have repeatedly been interpreted in support of Röntgen’s postulate.
Image: Water molecules are excited with X-ray light (blue). From the emitted light (purple) information on H-bonds can be obtained.
Credit: T. Splettstoesser/HZB