EOSC 118 Lecture Notes - Lecture 7: Substitution Reaction, Chemical Formula, Formula Unit
Document Summary
Each mineral has its own distinct prosperities, including chemical composition (or formula). The chemical composition of the mineral is represented by a chemical formula which includes the component elements and the number of atoms of each element written as a subscript. Atoms per formula unit (apfu): gold = au, oxygen = o, silicon = si : the first letter is capital, the second is lower case. It"s called a solid solution and indicated that either magnesium or. Iron can occupy up to 2 atoms in the formula unit. All compounds (even minerals) must be charge neutral. This means that every positive charge has a negative charge to balance out. It"s an important concept for understanding elemental substitution of trace and minor elements in a mineral. Mineralogists and geoscientists often report the amount of a cation in weight percent (wt%) of its oxide form.
