discuss briefly the structure of cscl
Answers
The structure of CsCl can be described as:
(1).The cesium ions from the simple cubic arrangement.
(2).Chloride ions occupy the cubic interstitial sites, i.e., Each chloride ion has eight cesium ions as its nearest neighbours(3).If we consider the figure at left it can be observed that each cesium ion is surrounded by eight chloride ions which are also disposed towards the corners of a cube.4)It may be concluded that both type of ions are in equivalent positions, and the Stoic biometry is 1:1. The coordination is 8:8.
Explanation:
CsCl has a cubic structure that consists of an infinite chain of ions. The Cs (or Cl) ions sit at the eight corners of the cube and the Cl (or Cs) sit at the center of the cube (thus it is NOT a body-centered lattice since that requires the SAME ion to occupy the edges and center). The CN of both cation and anion is 8.
CsCl has a cubic unit cell. At first glance you might think that it is body-centered, but this would be true only if the atom at the body center was the same kind of atom as those on the corners of the cells. This is clearly not the case.
CsCl can be thought of as two interpenetrating simple cubic arrays where the corner of one cell sits at the body center of the other. As with NaCl, the 1:1 stoichiometry means that the cell will look the same regardless of whether we start with anions or cations on the corner. Note that each ion is 8-coordinate rather than 6-coordinate as in NaCl.
Structural Information
CsCl Vital Statistics
Formula CsCl
Crystal System Cubic
Lattice Type Primitive
Space Group Pm3m, No. 221
Cell Parameters a = 4.123 Å, Z=1
Atomic Positions Cl: 0, 0, 0 Cs: 0.5, 0.5, 0.5
(can interchange if desired)
Density 3.99
Melting Point 646 degrees C
Alternate Names none
Isostructural
Compounds NH4X, TlX (X = halide), CuZn (beta-brass),
AgZn, LiHg, MgSr
