Rock salt structure type example compounds

The structure of NaCl, table salt, rock salt, or halite (name of the mineral) is the most important and most common one for MX-type salts. Hundreds of salts have this structure, and many examples are listed in Table 5.1. It is characteristic of ionic MX-type compounds except for those with large differences in sizes of cations and anions. The coordination number (CN) is six for both ions for NaCl. Large cations, particularly with small anions, prefer a larger CN, commonly CN = 8 as in the CsCl structure. Small cations, and particularly for compounds with significant covalent character, prefer the CN = 4 as in ZnS. 

A majority of the important oxide ceramics fall into a few particular structure types. One omission from this review is the structure of silicates, which can be found in many ceramics [1, 26] or mineralogy [19, 20] texts. Silicate structures are composed of silicon-oxygen tetrahedral that form a variety of chain and network type structures depending on whether the tetrahedra share comers, edges, or faces. For most nonsilicate ceramics, the crystal structures are variations of either the face-centered cubic (FCC) lattice or a hexagonal close-packed (HCP) lattice with different cation and anion occupancies of the available sites [25]. Common structure names, examples of compounds with those structures, site occupancies, and coordination numbers are summarized in Tables 9 and 10 for FCC and HCP-based structures [13,25], The FCC-based structures are rock salt, fluorite, anti-fluorite, perovskite, and spinel. The HCP-based structures are wurtzite, rutile, and corundum. 

Many compounds with a polyatomic cation and/or anion assume a rock salt-type structure. These range from KSH, KCN, and NH4I, where the polyatomic ions are fairly simple (see Table 7.9), to a more complicated example such as hexaam-minecobalt(III) hexachlorothallate(III), [Co(NH3)g] [TlClg], where both the cation and anion are complex ions. In all these cases, the anions assume an fee array and the cations occupy the octahedral holes. 

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