Normally, these reactions do not involve oxidation or reduction. Whether or not a precipitate forms depends on the exact combination of salts used. Heating an oxysalt produces a metal oxide plus a nonmetal oxide or a metal salt plus oxygen , or some combination of these two decomposition reactions. Heating a hydrated material initially causes a decomposition reaction to produce the anhydrous compound and water. Further heating may yield further decomposition, depending on the material.
Most binary compounds are stable to heat.
Reaction of an element with a compound often gives a single replacement reaction in which a nonmetallic element can replace a combined nonmetal, and a metallic element can replace a combined metal, or hydrogen from an acid. In these two series, one element can replace another one to its right in the series. Some of the transition elements form oxyanions as well as cations. It is impossible for oxidation to occur without reduction or vice versa.