compounds and molecules

molecule 分子
The smallest particle of a substance that retains the chemical and physical properties of the substance and is composed of two or more atoms; a group of like or different atoms held together by chemical forces.
<two or more atoms> --- same or different elements
compound 化合物
A substance formed by chemical union of two or more elements or ingredients in definite proportion by weight
<two or more elements> --- different elements
compound 化合物　可分為covalent compound和ionic compounds
covalent compound is compound formed by covalent bond 共價鍵
ionic compound is compound formed by ionic bond 離子鍵
I hope this can help with your understanding. =)

no difference
they are &quot; matter &quot;