Compounds
Chemical compound is a chemical substance that is bound by two or more elements in a fixed molar by chemical bonds. The compound can be decomposed into a simpler chemical by chemical reaction. Like methane (CH4), glucose (C6H12O6), lead sulfate (PbSO4) and carbon dioxide (CO2) are compounds. Compounds are classified under pure substances, as opposed to elements and mixtures. Although in some cases the actual situation of the compound will be deviated from the above definition, such as the composition of the elements with the preparation method changes, the internal structure is not uniform, the distribution of different nuclides is not fixed, etc., but generally still think they belong to the scope of compounds. In addition, the molar ratio of the elements in the compound is not necessarily an integer, and an element may be in a different valence state, such as an achromatic compound and a mixed valence compound. Chemical elements of the element even if the formation of several atoms by two atoms or polyatomic molecules (such as H2, S8), nor is the compound. In addition to the particularly inactive rare gas helium and neon, all other stable elements have been made of compounds. The preparation of rare gas compounds has cost some twists and turns. The first rare gas compound hexafluorobitrate xenon was prepared in 1962. ...