Final answer:
In solid form, cesium chloride (CsCl) consists of a simple cubic structure with cesium and chloride ions forming a 1:1 stoichiometry, each with a coordination number of 8, arranged in an interpenetrating cubic lattice.
Step-by-step explanation:
In cesium chloride (CsCl), which exists in solid form, the cesium ions (Cs+) and chloride ions (Cl−) form a distinctive crystal structure due to their similar sizes and 1:1 ratio. This ionic compound is characterized by a simple cubic unit cell, with each cesium ion positioned at the center and surrounded by eight chloride ions at the corners of the cube. Vice versa, each chloride ion is also surrounded by eight cesium ions.
This arrangement provides a coordination number of 8 for both Cs+ and Cl−. Importantly, the cesium chloride structure can also be viewed as two interpenetrating simple cubic lattices, with each type of ion occupying an octahedral hole within the other's lattice, resulting in a 3-dimensional network that defines the solid structure of CsCl. Notably, the Cs+ ion is significantly larger than the Na+ ion, which is why CsCl and NaCl exhibit different crystal packing arrangements.