Chemical compounds (ie a molecule that contains atoms of more than 1 element) are represented by formulas that show the number of the different atoms in the molecule. Show the number of atoms of each element in the molecule in the right-hand subscript position:

In general texts, it is best to write out simple chemical compound names in full, wherever possible (eg carbon dioxide, methanol, sodium acetate); however, in technical reports and scientific journal papers, it might be appropriate to use the symbol (especially in tables and figures). If abbreviations for chemical symbols are used, consider identifying them in full at first use in text, and in notes under tables or figures:

Use spaces between ions and neutral segments of a chemical compound when written in full, but keep chemical formulas without spaces: