Combinations of Elements
Element Combination
Likely Structure
Nonmetal and nonmetal
Discrete molecule
CO
2
, PCl
3
, NO
Metal and metal
Extended (alloys)
CuZn (brass), NiTi
Metal and nonmetal
Extended (salts)
NaCl, ZnS, CaTiO
3
Predict when to expect discrete molecular compounds vs. extended structures.
Compounds formed between nonmetals and other nonmetals tend to be relatively small discrete molecules.
Compounds formed between metals and nonmetals and between metals and other metals tend to form solids with extended structures.
Metallic elements form solids with extended structures.
