Magnetic Properties of Chemical Substances

If the counter consisted of N windings and the magnetic flux penetrated aU of them without omission, then the total magnetic flux linkage P is equal to T = or 

Excitation of an induction e in a closed counter when a current change is taking place is referred to as self-induction. It is equal to the speed of flux linkage P change taken with the sign minus  

In order to calculate the inductance of a long solenoid, we can use an expression for the total magnetic flux (Ampere law) P = L/ and P = = nIBS (where n is the number 

It can be seen that the solenoid inductance depends quadratically upon the number of windings on a unit length and is proportional to the solenoid volume. In the absence of a ferromagnetic core the inductance is constant and is not dependent on the current strength. 

From the point of view of their reaction to an external magnetic field, aU substances are referred to as magnetic. Its chemical structure defines the magnetic properties of a substance. All magnetic materials can be divided mainly into three main classes diamagnetic, paramagnetic and magnetically ordered substances. 

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The investigation of the physical properties of inorganic substances. This may be undertaken with a view to exploiting practical applications, or to obtain chemically-relevant information from the physical measurements. Magnetic measurements, for example, may tell us something about the electronic structure and bonding in a coordination compound. 

An electron s position in an atom or ion can be described by determining its electron configuration and orbital diagram. These representations of an atom or ion can explain physical and chemical properties of the substance, including magnetic attraction. 

In some substances there are two (or more) identical ions in different chemical environments or differently oriented with respect to the crystallographic axes. In a bulk-susceptibility measurement, only the average magnetic properties of both ions could be determined, but even slight differences between them will result in their resonance frequencies being detectably different in an esr measurement. 

The basis for the elaboration of this dynamist chemistry was provided by the sensible qualities of chemical substances. The explanation supposed that matter was animated by forces — magnetic, electric, chemical — with opposite polarities responsible for the phenomenal quahties of the matter. This treatment of qualities was inspired by Kant s notion of intensive quantity that he proposed in his Metaphysical Foundations of Natural Science from 1786. In contrast to form and motion, intensive quantities are not amenable to mathematical representation, but can nevertheless be handled quantitatively as non-additive quantities. The science of stoichiometry developed by Jeremias Richter (1762—1807) (one of Kant s students) illustrates this approach nicely. Wanting to introduce a mathematical approach to experimental chemistry, Richter quantified the properties of being acidic or basic by placing them on a scale, thereby allowing him to determine the proportions of the reactants involved in the formation of salts, leading to his proposal of the law of neutralization. 

Before describing the magnetic properties of a chemical substance we will briefly discuss some of the properties of a magnetic field itself. Whereas the sources of an electrostatic field are motionless electric charges, the sources of a magnetic field are moving charges, i.e., an electric current. Let us consider some characteristics of a permanent electric current and the conditions of its maintenance. 

Consider now a number of examples that will allow us to see how the structure of chemical substances influences their magnetic properties. 

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