ISSN 1070-4272, Russian Journal of Applied Chemistry, 2008, Vol. 81, No. 10, pp. 1860–1862. © Pleiades Publishing, Ltd., 2008.
Original Russian Text © I.B. Sladkov, 2008, published in Zhurnal Prikladnoi Khimii, 2008, Vol. 81, No. 10, pp. 1740–1742.
Prognostication of Properties of Molecular Inorganic Fluids
from the Stoichiometric Formula of a Compound
I. B. Sladkov
St. Petersburg State Polytechnic University, St. Petersburg, Russia
Received June 6, 2008
Abstract—A method is suggested for prognosticating the physicochemical properties of molecular inorganic
fluids in the total absence of experimental information about the properties of a substance under study. The method
makes it possible to determine quite a number of properties on the basis of only the stoichiometric formula of
At present, prognostication of properties of mo-
lecular inorganic fluids requires information about at
least a single experimental characteristic of a substance
under study, its boiling point [1, 2]. Methods for prog-
nostication of the boiling point itself cannot be found
in the literature, and, therefore, “blind” prognostication
of physicochemical properties, i.e., that in the total
absence of input information about the substance under
study, is also impossible.
In this communication, a method for prognostica-
tion of the boiling point and a number of other proper-
ties of molecular inorganic fluids is suggested. This
method doers not require any evidence about the com-
pound under study, except its stoichiometric formula.
The first step in the development of the technique
was a search for a correlation that could be used for
estimating the boiling points of molecular inorganic
fluids. It was found that this can be done using the cor-
relation between two determinative criteria of thermo-
dynamic similarity. One of these was described in de-
tail in :
the stoichiometric formula of a compound ; and
, molar volume of the fluid at the boiling point
A set of compounds, constituted by several tens of
molecular inorganic compounds, was used to establish
a correlation between the criteria mentioned above:
ψ = 0.1ln
f = ln
Π – 4,
and the other, in :
is the standard boiling point (K); Π, parachor
) calculated by an additive method from
f = 6.8ψ + 0.21.
Relation (3) served as a basis of an iteration that
enables calculation of the boiling point and quite a num-
ber of physicochemical properties of the substance. This
correlation includes a set of the following formulas
taken from [3, 4].
Initially, a first approximation to the boiling point
= 200) and molar volume of the fluid at the boil-
ing point V
= 27Π) are set.
Then, two determinative criteria of thermodynamic
similarity, f and ψ, are calculated by formulas (1) and (2).
Further, the boiling point is found in a second approx-
imation and a number of physicochemical properties
= exp[6.8ψ + 1.1ln Π + 4.21],
= 1.5 T
= (–6.2f + 31.2)Π
b = 1.27V