A compound is made up of individual elements through the process of bonding and has different properties than the constituent elements. For example, oxygen is a catalyst for combustion and hydrogen is highly flammable and are both gases; yet these two combine to form water, which extinguishes fire and is a liquid. The properties of a compound depends upon the type of bonding that formed the compound. For example, ionic compounds (formed by donation and acceptance of electrons between different elements) conduct electricity, when dissolved in water. In comparison, covalent compounds do not conduct electricity. Similarly, ionic compounds are more tightly held together as compared to covalent compound and hence much harsher treatment may be required to break the bonds in an ionic compound. Ionic compounds also tend to have higher melting and boiling points.
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