Molar Mass ($M$): The mass in grams of one mole of chemical entities ($6.022 \times 10^{23}$ particles). Computed by summing the standard atomic weights of all constituent atoms.
Nested Brackets & Hydrates: Supports arbitrary nesting such as Al2(SO4)3·18H2O, [Cu(NH3)4]SO4·H2O, and K4[Fe(CN)6].
Empirical Formula: Simplest whole number ratio of atoms in a compound derived from experimental mass percent data.