| # | Concept | Culture | Statement | Freq. |
|---|---|---|---|---|
| 1 | hafnia | scientific community | Hafnia is a chemical element with the symbol Hf and atomic number 72, named after the Latin name for Copenhagen, where it was discovered. | 1 |
| 2 | hafnia | scientific community | Hafnia is a chemical element with the symbol Hf and atomic number 72. | 1 |
| 3 | hafnium | scientific community | Hafnium is used in nuclear reactors and as an alloying agent in metals. | 1 |