| This qualifier is the general description for the common allotropes of elemental phosphorus. |
| Arsenic has two allotropes, yellow arsenic and metallic arsenic, which is brittle. |
| The element normally exhibits six allotropes and four oxidation states. |
| The presence of these many allotropes makes machining plutonium very difficult, as it changes state very readily. |
| Each of these allotropes of phosphorous also has its own subset of forms. |
| Lead's lighter carbon group congeners form stable or metastable allotropes with the tetrahedrally coordinated and covalently bonded diamond cubic structure. |
