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What physical properties does pure sulfur have?

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A labeled diagram highlights sulfur's position on the periodic table, showing its atomic number 16, symbol S, atomic weight range, electron configuration, and classification as a solid, strongly acidic, orthorhombic nonmetal at room temperature. — sulfur Chemical properties of sulfur.

Pure sulfur is a tasteless, odorless, and brittle solid that is pale yellow in color. It is a poor conductor of electricity and is insoluble in water.1

Sulfur exhibits allotropy, meaning it exists in several different forms, including various crystalline and amorphous structures. Its physical properties, such as melting point and density, vary depending on the specific allotropic form:21

| Property | Rhombic ( $α$ -sulfur) | Monoclinic ( $β$ -sulfur) |
| :--- | :--- | :--- |
| Melting Point | 112.8 °C (235 °F) | 119 °C (246 °F) |
| Density (at 20 °C) | 2.07 g/cm³ | 1.96 g/cm³ |

When heated, sulfur melts into a yellow, transparent, mobile liquid. As the temperature increases further, its viscosity and color change significantly—deepening from yellow to dark red and eventually black—due to shifts in its molecular structure. The boiling point of sulfur is 444.6 °C (832 °F).21