Why the crystal structure of the element is such lattice but not another?

+q

-q

а) б)

Figure 1. Schematic representation of the conduction band of two different metals. (scale is not observed).

a) - the first variant;

b) - the second variant.

The order of electron movement will also be affected by the structure of the conductivity zone, as well as by the temperature, admixtures and defects. Magnetic quasi-particles, magnons, will have an impact on magnetic materials.

Since our reasoning is rough, we will further take into account only filling with electrons of the conductivity zone. Let us fill the conductivity zone with electrons in such a way that the external electrons of the atomic kernel affect the formation of a crystal lattice. Let us assume that after filling the conductivity zone, the number of the external electrons on the last shell of the atomic kernel is equal to the number of the neighbouring atoms (the coordination number) (5).

The coordination number for the volume-centered and face-centered densest packings are 12 and 18, whereas those for the body-centered lattice are 8 and 14 (3).

The below table is filled in compliance with the above judgements.

ElementRH . 1010

(cubic metres /K)Z

(number)Z kernel

(number)Lattice type

NatriumNa-2,3018body-centered

MagnesiumMg-0,9019volume-centered

Aluminium OrAl-0,3829face-centered

AluminiumAl-0,38112face-centered

PotassiumK-4,2018body-centered

CalciumCa-1,7819face-centered

CalciomCaT=737K28body-centered

Scandium OrSc-0,6729volume-centered

ScandiumSc-0,67118volume-centered

TitaniumTi-2,4019volume-centered

TitaniumTi-2,4039volume-centered