IMAT Chemistry Practice Exam

A macro covalent lattice refers to a solid where covalent bonds extend throughout the entire crystal, creating a giant three→dimensional network. In such a structure every atom bonds to several neighbors in all directions, so there are no discrete molecules inside the solid. Because breaking this lattice means breaking many strong covalent bonds, these materials have very high melting points and are exceptionally hard and insoluble. Diamond is a classic example, with each carbon forming bonds to four others in a rigid framework. This contrasts with ionic lattices, which are held together by electrostatic forces between ions; metallic lattices, which consist of metal cations in a sea of delocalized electrons; and simple covalent lattices that don’t form the same extended network throughout the crystal. Hence, the term macro covalent lattice best describes substances like diamond and other giant covalent networks.