What is the limitations of radius ratio rule?
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What is the limitations of radius ratio rule?
The size of a cation of a compound can be determined by the critical radius ratio according to Pauling’s rule of crystal structure. Limitation: This rule is applicable when all the cations and anions are perfectly sphere but in maxium cases the atoms or ions are not perfectly sphere. Hence deviation arises.
What is the effect of radius ratio on coordination number?
As the radius ratio becomes smaller than this, triangular coordination becomes the stable configuration. For triangular coordination, the coordination number is three, that is 3 anions surround the smaller cation. The “no rattle” limit is reached for triangular coordination when Rx/Rz becomes less than 0.155.
What is radius ratio effect?
A crystal structure is determined by the ratio of ionic radii of its components . This ratio coordinates the coordination number of the smaller ions. In ionic crystals each ion is surrounded by definite number of the oppositely charged ions.
What is the basis of radius ratio rule?
The ratio of radius of cation to anion is called radius ratio. In condensed matter physics and inorganic chemistry the cation-anion radius ratio (also: radius ratio rule) is the ratio of the ionic radius of the cation to the ionic radius of the anion in a cation-anion compound.
What is the radius ratio of tetrahedral void?
0.225
Radius ratio of Tetrahedral void is 0.225.
When the radius ratio lies between 0.732 and 0.414 the arrangement of crystal is?
Thus, if the radius ratio of an ionic compound is in the range 0.414-0.732, then the geometry of voids is octahedral….Complete answer:
| Radius ratio | Coordination number | Geometry of holes (voids) |
|---|---|---|
| 0.414-0.732 | 6 | octahedral |
| 0.732-1.00 | 8 | cubic |
How does radius ratio help in determining the structures of compounds?
Answer: It also helps to determine the stability of an ionic crystal structure. For instance, larger cations will fill the larger voids like cubic sites whereas smaller cations will fill the smaller voids such as tetrahedral sites. Hence, the radius ratio rule helps in determining the structure of ionic solids.
Which ionic crystal shows Schottky and Frenkel defects?
AgBr
AgBr shows both Frenkel and Schottky defects because the radius ratio for AgBr is intermediate.
How does radius ratio help in determining the structure of compound?
What is void radius?
Relation between radius of tetrahedral void and radius of atom. There spheres form the triangular base, the fourth lies at the top and the sphere occupies the tetrahedral void. Let the length of the side of the cube =a. From right angled triangle ABC, face diagonal. AB = AC2+BC2 =a2+a2 =2a2.
What is radius ratio in solid state?
The ratio of the radius of cations (r+) to the radius of the anion (r–) is known as the radius ratio of the ionic solid. The significance of radius ratio: It is useful in predicting the structure of ionic solids. Greater the radius ratio, greater is the coordination number of cations and anions.