The Nature Index 2025 Research Leaders — previously known as Annual Tables — reveal the leading institutions and countries/territories in the natural and health sciences, according to their output in ...

Catenanes are molecules in which two or more molecular rings are entangled like the links of a chain 2; indeed, their name derives from catena, the Latin word for chain. The rings are not connected by ...

Silica has a giant covalent structure containing silicon atoms (grey) and oxygen atoms (red) Learn more on properties of giant covalent compounds in this podcast. Listen to the full series on BBC ...

Atoms have a positively-charged nucleus made of protons and neutrons, and negatively-charged electrons that orbit the nucleus in shells. Bonding - (CCEA) Atoms and ions bond with each other in three ...