Caesium chloride

Caesium chloride (CsCl) is an ionic compound formed from caesium and chloride ions. Its anhydrous crystal has a cubic structure in which each ion is surrounded by eight oppositely charged ions.

Ionic bonding: Chemical bonding driven by electrostatic attraction between oppositely charged ions. Electrostatic attraction between caesium and chloride ions holds the solid together.
Unit cell: The smallest repeating volume whose translations reproduce a crystal lattice. A cubic unit cell depicts the repeating geometry of the CsCl structure.
Density-gradient centrifugation: A centrifugation method that separates particles according to their buoyant density in a density gradient. Concentrated CsCl solutions form gradients that can separate nucleic acids by buoyant density.
Sodium chloride structure: A crystal structure in which each ion has six nearest neighbors of opposite charge. NaCl has sixfold coordination, unlike the eightfold coordination in CsCl.
Caesium ion: The positively charged Cs⁺ ion formed when a caesium atom loses one electron. Cs⁺ occupies one of the two interpenetrating sublattices in crystalline CsCl.
Body-centered cubic: A cubic lattice with equivalent lattice points at each cube corner and at its center. Its lattice-point geometry resembles CsCl, but its corner and center sites are equivalent.
Buoyant density: The density at which a particle neither rises nor sinks in a surrounding medium during centrifugation. DNA bands in CsCl gradients at the position matching its buoyant density.
Zinc blende: A cubic crystal structure with fourfold coordination, adopted by compounds including zinc sulfide. Its tetrahedral coordination contrasts with CsCl’s cubic eightfold environment.
Chloride ion: The negatively charged Cl⁻ ion formed when a chlorine atom gains one electron. Cl⁻ alternates with Cs⁺ throughout the crystal lattice.
Simple cubic: A cubic lattice with lattice points only at the eight cube corners. Unlike simple cubic packing, CsCl has a second ion at the cube center.

Linked from 1 page