Californium
From Memory Alpha, the free Star Trek reference
| Name: | Californium |
| Symbol: | Cf or Ca |
| Atomic Number: | 98 |
| Atomic Weight: | 19 |
Californium is a chemical element listed on the Table of Elements. (TNG: "Rascals")
The element californium had the symbol "Ca", which is the same atomic symbol used for calcium. The producers might have created the name not knowing it was an actual element.
