The Essential Pattern

In a two-page account, Partington (1951) refers to water as a mixture of polymerized water molecules and cites about 80 papers. In his inaugural lecture (1963) Ives talked about his reflections on water, referred to the thermodynamic studies of Frank and his co-workers, and quoted a comment that Rowland made in 1880.  

Emerging from detailed studies of the way the various properties of water change with temperature, and from X-ray work (Bernal and Fowler, 1933) and Raman spectra (Rao, 1934), is the essential pattern of hydrogen-bonding structure, herein designated for convenience as (H20) , in which the units H2O are linked in a system of dynamic equilibria. It is of vital importance to distinguish the symbol H2O , which should refer precisely only to the molecule 

Attempts have been made to involve and explain all the changes in the properties of water as the temperature changes, or as energy is added. There is disagreement over details. I look upon the dipole-dipole attraction of the unbonded (not hydrogen-bonded) H2O units as constituting an acid-base function, and I am left with the essential pattern for the present purpose, which may be symbolized simply as (H20) . 

At the Faraday Society discussion of 1967, Frank emphasized the point that he knew of no one who believed there are any free H2O molecules in liquid water, considered as a mixture— free in the sense in which a molecule is free in the dilute vapor.  

Magat referred to the problem of free water molecules and mentioned contradictory results relating to the existence of freely rotating water molecules, which he believed can probably be looked upon as not hydrogen-bonded water. 

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When atomic theory developed to the point where it was possible to write specific formulae for the various oxides and other binary compounds, names reflecting composition more or less accurately then became common no names reflecting the composition of the oxosalts were ever adopted, however. As the number of inorganic compounds rapidly grew, the essential pattern of nomenclature was little altered until near the end of the 19th century. As a need arose, a name was proposed and nomenclature grew by accretion rather than by systematization. 

For the purposes of the MS-Xa calculation the core was assumed frozen, and on uranium only the 6s, 6p, 5/, 6d and 7s orbitals were considered. (Fig. 19, which also comes from Ref. [60], shows why, at a typical metal-oXygen distance of 175 pm (3.3 a.u.) it is necessary to consider the charge distribution in all these orbitals.) The eigenvalues from this calculation are included in the first column of Table 3. Despite its neglect of relativistic effects, this approach describes the essential pattern of the bonding orbitals. However, the HOMO-LUMO gap is underestimated, and the HOMO, described as ng, is not consistent with the experimental symmetry. 

The distribution of kaolinite in marine sediments (Fig. 1.15) depends on the intensity of chemical weathering at the site of the rock s origin and the essential patterns of eolian and fluvial transport. Due to its concentration at equatorial and tropical latitudes, kaolinite is usually referred... 

To get Xa/Pa and Na/Pa data for the revelation of the essential patterns, I have used liquids S of low-enough volatility because I have wished to draw off only gas A from the mixture of A+S by lowering the total pressure. 

It is difficult to be precise about accuracy because so much depends upon the system and temperature. For liquids S of low volatility the degree of accuracy is deemed to be within 4%. This affords reliable data for the essential patterns. Time-consuming modifications leading to a precisely specifiable accuracy will be revealed to one who becomes skilled in the art. ... 

By means of the bubbler-tube-manometer procedure/ I determine the mass of n-butane absorbed by a known mass of a liquid S at fC and Pbuh> the pressure of gaseous n-butane. The apparatus constrains me to measure only the total pressure, which is made up of Pbuh and ps- To allow for ps is a protracted operation, as I shall show later but to build up the essential pattern of data for my present purpose, I use liquids which have a low-enough ps to be neglected. Therefore, I take the observed total pressure to be essentially equal to Pbuh- In the conventional terminology the expression partial pressure is used, i.e., Pbuh and ps would be called partial pressures. I do not like this, and see no need for it. To me Pbuh is the pressure due to n-butane, and ps that due to S the measured pressure is Pbuh + Ps ... 

Figure 7 shows representative lines for 25°C, and also for —5°C. The essential pattern is the same for each temperature, the main factor being the tendency to condense. At -5°C, the system is, in conventional terms, a liquid-liquid one, similar... 

The Na value for a liquid S will then be determined by the mechanisms of the inevitable interaction of A with S in the dissolution process. The liquid S itself has its own pattern of acid-base function sites which give what is herein referred to as intermolecular structure. There are no simple rules, but there are clear trends which, by the exercise of intuition backed by chemical knowledge, enable one to appreciate and to rationalize the essential pattern of data. 

Allowing for limitations of the data, it is seen that they fit into the essential pattern for the gaseous hydrocarbons. At 0°C the value for n-hexane is a little higher than the R-line value, whereas the value for aniline is at the low end still lower is the value for glycerol, and that for water even lower. The series of n-carboxylic acids shows a steady increase in Xr values, from Xr = 0.00162 for HCOOH at 25 C, pn 760 mm up to 0.0617 for C7H15COOH, a value approaching the R-line one of 0.0665 (Fig, 62). The plot is almost linear up to C5 and then begins to flatten. The more restricted series of n-alcohols, MeOH to n-BuOH, also show an almost linear plot. See refs. 4, 30, 31, 123, 330. 

O Brien and Bobalek (1940) gave m and Phbf (up to 358 mm Hg) data for hydrogen bromide, benzene, toluene, and o-nitrotoluene at 25 C. I have plotted the XHBr and NnBr values up to the upper limits of pnBr in Fig. 94 and have indicated the probable extrapolations. These authors plotted log p vs log N and thereby obliterated the essential pattern. To get the theoretical line for that plot, they took the fugacity as 18.3 atm for 25°C, but again they used pressures observed as Phbf for their solubility measurements. In terms of Phbf = km, these authors concluded that Henry s law was followed, but there was a negative deviation from Raoult s law. 

An analysis of a patent specification on this procedure affords an example of the effectiveness of the R-line approach in bringing into focus the essential pattern of... 

In Table 49,1 illustrate the essential pattern of data for helium at 1 atm. 

The solubility of gases and liquids in liquids is of great importance in large areas of operations based on chemical concepts. Phenomena have appeared to be so varied that even experts have from time to time remarked on the difficulty of seeing a consistent pattern. Now for the first time the essential pattern of all known gas solubility data is set out in a graphic form for all to see. The continuous merging of the gas-liquid systems and the liquid-liquid systems is also illustrated. The pattern opens the way to rational predictions. 

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