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llest patterned collectionTHE BOND-ENERGY CURVE characteristic angle between an atom
or ionwas introduced its volume of a material per unitis most
The bond-energyfractional change in Section 2.4.1. Several important macroscopic
curve and two of in nearest neighbors. The term change
material properties can used to describe from this curve. Speciﬁcally,in covalent
often be obtained directly speciﬁc bond angles one can estiin temperature.
ion at a lattice site that
mate the bond energy, the average bond length, the elastic modulus, and the coefﬁcient
structures. removal of surface material as a result of
of thermal expansion. Each of these characteristics of the curve will be discussed in some
mechanical rather than chemical interaction.
ergy electron band that is this section. energy The amount of energy required to move
Recall that the function U can be interpreted as the amount of work done by the system is
two atoms or ions to an inﬁnite separation distance. It
A together used to join two or, equivalently, the
when two ions orwelding broughtprocessfrom inﬁnite separation pieces of metal in
equivalentbe supplied to theof thethe order toand awell.separate
to the depth near bond-energy ﬁller metal
located in the shell that is of energy that must parent metal system in joint completely
the atoms from bond-energy curvethe melt and of U well)x 0 , or to form a that
one another. Therefore, (bond-energy x at
are heated until they magnitude mix togetherThe depth of
the energy well, is a measure of the inherent strength of the bond, or the bond energy.
describes theupon freezing.
strong joint energy the equilibrium separation distance x0 correIn
of secondary bond in addition, we have already pointed out that associated with a pair of atoms or
process in which a metal two atoms
ces another dipole in sponds bond-energylength.a functionAvariationdistance w...
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