Anomalous Properties Of Water Research Articles

Limits of stability of the liquid phase in a lattice model with water-like properties

Explicit study of the hydrogen bond network in water offers a microscopic approach to understanding the anomalous properties of water, while an alternate, thermodynamic approach is offered by the reentrant limit of stability (spinodal) conjecture. To relate the two approaches, we develop a lattice model based on microscopic considerations. We show that the model displays anomalous thermodynamic behavior that is in qualitative agreement with the behavior of water. We study the model in the mean field approximation and by numerical simulations. We explicitly demonstrate the interrelation between density maxima and the reentrance of the spinodal: both originate from the contribution of orientational degrees of freedom to the thermodynamics of the system. The metastable liquid state is bounded by a spinodal at positive pressures as well as negative pressures, where the positive pressure spinodal is the limit of stability with respect to the solid state. The liquid–gas and liquid–solid spinodals form a continuous locus, but the ‘‘critical’’ properties of these two spinodals are quite different. While the response functions (specific heat, compressibility) diverge at liquid–gas spinodal, at the liquid–solid spinodal they do not—even though the response functions tend to higher values in the same fashion as occurs near the liquid–gas spinodal.

Anomalous properties of water in macromolecular gels

Low molecular weight studies often exhibit elution characteristics on gel filtration columns which deviate from ideal behaviour. In many previous studies this anomalous behaviour was attributed to the existence of extremely narrow pores in the gel, inaccessible even to very small solute molecules, to explain K d values lower than unity. K d values of small solutes higher than unity were usually ascribed to adsorption of the solute to the gel matrix. In the present paper several observations are presented that contradict these suggestions. Experimental evidence indicates that with small solute molecules K d values differing from unity can be fully explained by the anomalous properties of vicinal water layers at the gel matrix-water interface.

The distribution of rings of hydrogen-bonded molecules in a model of liquid water

We report the results of calculations, at five temperatures ranging from 243 to 313 K, of the distributions of non-short-circuited rings of hydrogen-bonded molecules in TIPS-2 water. These data are used to test two hypotheses concerning the use of ring transformations as collective excitations in water. The suggestion by Speedy that it is the concentration of five-membered rings that determines the anomalous properties of water, and the suggestion by Rice, Belch, and Sceats that it is the ‘‘reactions’’ 2(6 ring)⇄(5 ring)+(7 ring) and 8(6 ring)⇄2(4 ring)+4(8 ring) that determines these properties, are both shown to be incomplete. Further verification of the random network model assumption of separation of time scales for network relaxation and local molecular motion is presented.

Aqueous solutions. Part 3.—Thermal and acoustic characteristics of water

The relaxational functions for the expansivity of water have been derived using the relaxational compressibility functions obtained previously. The expansivity can be interpreted in terms of a bond-breaking model whereby the anomalous component is associated with the 1-bonded and 0-bonded OH groups. The relaxational heat capacities have been estimated from the corresponding compressibilities and expansivities.On the basis of evidence from acoustic data, which indicated the possibility of a thermal relaxation, the anomalous heat capacity has been resolved into two components Cpy1 and Cpy2. Cpy1 values follow a critical law and are similar to those obtained from extrapolations of binary solution and high-pressure data. Cpy2 is associated with the thermal relaxation.Overall the results show that the 1-bonded and 0-bonded equilibrium is probably the critical factor underlying the anomalous properties of water, and that the activation mechanism for this equilibrium could be a quantal one. That is, a time delay in the redistribution of energy between vibrational and rotational (or purely rotational) degrees of freedom could govern the hydrogen-bond equilibrium. The ‘dispersion’ hydrogen-bond energy, δH, identified previously, is of the right order to represent the quantum energy involved.

Water Revisited

Liquid water consists of a macroscopically connected, random network of hydrogen bonds, with frequent strained and broken bonds, that is continually undergoing topological reformation. Anomalous properties of water arise from the competition between relatively bulky ways of connecting molecules into local patterns characterized by strong bonds and nearly tetrahedral angles and more compact arrangements characterized by more strain and bond breakage. However, these alternatives constitute virtually a continuum of architectural possibilities rather than a discrete pair of options. The singular behavior of supercooled water near -45 degrees C and the "hydrophobic" attraction between nonpolar entities are due to the same underlying phenomenon, namely, the clumping tendency of relatively strain-free convex cages or polyhedra.

Temperature and pressure dependence of self-diffusion, viscosity and nuclear relaxation times in liquid water

A scaled particle-quansilattice model for liquid water, which is based on the ice VII and ice fc structures, is shown to be capable of explaining several anomalous properties of water. The non-Arrhenius temperature dependence of coefficients of self-diffusion and viscosity and nuclear relaxation times are quantitatively interpreted. Negative volumes of activation, which are observed for viscosity and nuclear relaxation, are also computed to be in good agreement with experiment.

Investigation of the properties of water II

When water vapor condenses on the surface of silica (such as fused quartz) either normal water or “anomalous” water may form, depending on the conditions of condensation. Studies of the kinetics of evaporation and condensation together with studies of phase separation in anomalous columns at sub-zero temperatures show that anomalous water is a solution of a less volatile component, which we call water II, in ordinary water I. By means of physicochemical microanalysis procedures specially developed in these studies we measured the density, refractive index, saturated vapor density, heat of evaporation, and thermal stability of water II. The molecular weight of water II was determined from the vapor pressure lowering of its solution in water I and found to be 180 ± 40. Corroborating results were obtained when the molecular weight was determined by the melting point and from the curve of phase separation at subzero temperatures. The only explanation that fits all our data is that water II consists of associated water I molecules. Further development of the “polymer” hypothesis of water II is due to Lippincott, Stromberg, L. Allen, and other U.S. scientists, and is supported by the results of infrared spectrum studies. Lippincott's work also confirms our data on modifications of methyl alcohol and acetic acid. Another hypothesis, often put forward to explain all these phenomena, the contamination hypothesis, cannot account for all of the experimental data. The hypothesis attributing the properties of anomalous water to organic impurities was disproved by analytical measurements carried out by us in collaboration with the laboratory of V. L. Talroze and by the surface tension determinations of anomalous water. Dissolving water II in water I was found to increase the surface tension of water I by several percent, which contradicts the idea that water II can be traced to organic impurities. It appeared from the start that the properties of anomalous water could not be due to leaching of the quartz containers; this contention is supported by the results of electron probes and by other data. The idea of accidental inorganic contamination is refuted by the consistent reproducibility of the phenomenon and properties of water II, obtained in our laboratory and under various conditions. Finally, the conversion (to within 10%) of the mass of water II to water I when distilled over a thermal barrier of sufficiently high temperature is also evidence that water II is a polymer of water I.

What can theory say about the existence and properties of anomalous water?

An important, but little practiced, function of theory is to provide working models that unify and summarize experimental findings during the time when basic understanding of a phenomenon is actually evolving. Such a model for anomalous water has been previously proposed by us [ Science, 167, 1443 (1970)]. This model attempted to explain the phenomenon as (H 2O) n with a new type of chemical bonding, and its ability to correlate existing data is brought up to date in this paper. However, three new results invalidate our original model: (a) high-accuracy ab initio calculations showing that symmetric hydrogen bonds are 5 kcal/H-bond higher in energy than the usual asymmetric hydrogen bonds, (b) calculations showing absence of a strong, long-range wall effect, (c) a molecular weight measurement by Derjaguin et al. indicating an average value of 180. Because our original model did so well in consistently correlating such a wide variety of experimental data, our present disproof of this model leads us to conclude that polywater does not exist. Experimental reports suggesting a collection of organic and/or inorganic impurities as the origin of the properties attributed to anomalous water are critically analyzed and found inconclusive. Three other related hypotheses are examined theoretically and also found inadequate. Another working model based on trace amounts of silicates plus inorganic and/or organic anions is proposed on theoretical grounds. A list of key experiments is offered to help elucidate the fundamental nature of the anomalous material and to test this model.

Anomalous water—Properties and factors affecting its yield

Anomalous water and the residue left when it is evacuated—“polywater”—has been prepared in fine capillaries and on quartz plates. Its properties have been examined and the factors affecting its yield explored. Yields of capillary-grown material are erratic. Thermal expansion and freezing data suggest similarity of this material to that reported in the Russian literature. A new result is that “polywater” contracts on solidification. This material is shown to decompose only slowly (within hours) at 650°C, and rather rapidly at 750°C. It is involatile at room temperature and survives mechanical displacement. It is deliquescent. Two factors have been shown to be important for determining the yield of anomalous water: the state of the glass surface and the instability of the vapor-surface environment. Hydrated surfaces give higher yields than surfaces partially dehydrated by heating. This result accounts for the variable and poor yields in as-drawn capillaries. Chemical surface treatments to modify the distribution of silanol groups on the surface have a profound effect on “polywater” yields. A strong maximum in yield is associated with a surface treated to contain only vicinal OH's. Experiments with crystalline quartz and Na +-implanted silica are also reported. Instabilities in the vapor-solid environment lead to sharply increased yields of anomalous water in capillaries. Pyrex capillaries are much more effective than quartz. It is shown that the product does not arise from impurities carried into the capillaries by creep of a liquid film from the water source over the surface of the cell. Rather, it results from a vapor-capillary reaction.

Some chemical and physical properties of anomalous water

Anomalous water samples were prepared by condensing water vapor into glass and quartz capillaries. The transfer of microliter quantities of anomalous water/water mixtures into larger capillaries suitable for further studies was accomplished by centrifugation. Some of the droplets showed optical anisotropy when viewed under a polarizing microscope. A density gradient method was developed to measure the specific gravity of anomalous water droplets. In anomalous water the rate of trypsincatalyzed hydrolysis of the chromogenic substrate N α -benzoyl-DL-arginine p-nitroanilide was less than 10% of the rate of hydrolysis observed in normal water. As reported earlier, the state of water associated with the enzyme carbonate hydro-lyase (EC 4.2.1.1) was studied by means of γ-γ directional correlation. With the use of the same technique and 133Ba tracer, a method was developed to measure and compare relaxation times and field symmetries in normal water, protein-bound water, and anomalous water condensed in capillaries.

Anomalous Water

Pethica, Thompson and Pike1 have attributed the properties of anomalous water to impurities. First, we wish to comment on their statement that the NMR study by Willis et al.2 gave no positive result. The expected resonance frequency shift has since been found in a study by Petsko3, who used a very sensitive method, so either the sensitivity of the apparatus used by Willis et al. was much lower, or they did not succeed in producing a sufficient amount of the anomalous component (water II). Petsko's results were confirmed by Page4 of the Battelle Institute of Columbus.

A review of the preparation and properties of anomalous water

A liquid that can be condensed into fine siliceous capillaries from unsaturated water vapour has properties very different from those of ordinary water. Is it a structurally modified form of water? This paper reviews the literature on this subject.

Anomalous Water, Porous Glass and Silicic Acid

THE detection of impurity ions has been regarded as an important feature of the study of polymerized water or anomalous water but chemical analyses have proved contradictory because of the extremely small quantities of material collected. Spectrochemical analyses by Lippincott et al.1 showed that there were only trace concentrations of cationic contaminants in their samples. Their limit of detection of relevant cations was 10−11 g, which suggests a cation concentration of less than 0.001%. Rousseau and Porto2, however, found high concentrations of cations (containing 20–60% Na) in anomalous water prepared in quartz capillaries. Rabideau and Florin3 found that a significant weight fraction of concentrated anomalous water residues consisted of Na, B(˜6%) and oxygen and pointed out the similarity of the physical properties of anomalous water and concentrated solutions of sodium tetraborate. Everett et al.4 reported that the colligative properties of anomalous water are consistent with those of a silicic acid gel.

The physical properties of anomalous water

The properties of anomalous aqueous condensates, prepared in the manner described by Deryagin,1 vary with aqueous vapour pressure. The changes of column length and of melting point are similar to those of ordinary aqueous solutions. There is no sound evidence that the condensate exhibits abnormal viscosity, density, electrical conductivity, or surface tension.

Anomalous Water: Characterization by Physical Methods

Anomalous water samples have been prepared in fused quartz capillaries from pure water in an unsaturated atmosphere. In agreement with observations of other investigators, water prepared in this manner, after concentration, exhibited an increased viscosity, a lowered vapor pressure, a phase separation at low temperatures, an index of refraction of 1.48 or greater, and a depression of the temperature of maximum density. However, electron microprobe examination indicated that a significant weight fraction of these concentrated anomalous water residues consists of sodium, boron, and oxygen. The presence of about 6 percent boron was also confirmed through neutron activation analyses and by mass spectrometric measurements. A parallel is drawn between the similar physical properties of anomalous water and highly concentrated sodium tetraborate solutions. The possibility of polymorphism in liquid water should be accepted only with serious reservations.

Colligative Properties of Anomalous Water

Investigations of the phase behaviour on freezing and subsequent melting and of other properties indicate that anomalous water is a solution containing a fixed amount of relatively involatile material in normal water. There seems to be no need to postulate the existence of a new polymer of water in such solutions. If only water and silica are present, the properties are consistent with those of a silicic acid gel.

"Polywater": A Hydrosol?

Measurements of the dielectric constant and the effective parallel conductance of a specimen of anomalous water suggest that anomalous water is a hydrosol consisting of finely divided particulate matter suspended in ordinary water. Scanning electron micrography confirms the presence of particulate matter. These new experimental data provide an alternative explanation for the properties of anomalous water.

Volume Viscosity of Liquid Antimony

Liquid antimony exhibits many of the anomalous properties of water. For example, its density increases on melting, and its compressibility shows a minimum as a function of temperature. As a further study of its properties, the absorption of ultrasound was measured in molten antimony at temperatures up to 900°C. The measured absorption is found to be higher than the absorption due to shear viscosity and thermal conductivity alone. The ratio volume/shear viscosity calculated from the excess absorption is 4.2. The significance of this result is discussed in relation to other properties and the structure of liquid antimony. [Work supported by a grant from the National Science Foundation.]