*Copied from CH3513 while I am yet to transfer the full note over.* **Defect Notation -** There are multiple systems for describing defects and solid solution reactions, the one used in this course is **Kröger-Vink.** - **Properties -** Good due to simplicity and ability to balance charge and mass. However, is not crystallographically useful _(e.g. only states interstitial site, not what coordinaton environment)._ $ \Large A^c_b $ - **A -** The species which is either the elemental symbol or _V_ for vacancy. - **B -** Location of the species in the crystal, denoted by the species that is normally present in the in the host crystal. - **Other Sites -** _i_ for interstitial; _s_ for surface. - **C -** The **effective charge** of the ion, i.e. the difference in charge between the species and the species that is normally present in the host crystal. - **Notation -** x or blank for no charge, • for positive charge, **′** for negative charge.