Potassium, rubidium.
In an alloy of gold and cadmium, gold crystallizes in cubic structure occupying the corners only and cadmium fits into the face centre voids.
Number of gold atoms =1/8 x 8 =1Au
Number of candium atoms =1/2 x 6 =3Cd
Hence, quantitative composition on = AuCd3
Both naturally-occurring and artificial quartz crystal contains at least ninety-nine percent silicone dioxide, while cut glass crystal only possesses at most eighty percent silicone dioxide.
When doping a semiconductor, such as the group IV element silicon (Si), with arsenic (As), a pentavalent n-type dopant from group V in the periodic table the dopant behaves as an electron donor.
Compounds having frenkel defect conduct electricity to a small extent. When electric field is applied, an ion moves from its lattice site to occupy a hole, it creates a new hole. In this way, a hole moves from one end to the other. Thus, it conducts electricity across the crystal. Due to the presence of holes, stability (or the lattice energy) of the crystal decreases.