Technetium (Tc) is a synthetic element, meaning it doesn't naturally occur in significant quantities on Earth. Here are 3 common compounds containing Technetium:

1. Technetium-99m pertechnetate (Tc-99mO4-): This is the most widely used radioisotope in nuclear medicine. It's used in diagnostic imaging procedures like bone scans, thyroid scans, and heart scans.

2. Technetium sulfide (TcS2): This is a black solid compound used in research related to the properties of technetium.

3. Technetium dioxide (TcO2): This compound is a dark-colored solid that forms when technetium is exposed to air. It's used in nuclear research and production.

It's important to note that technetium compounds are radioactive and should be handled with caution.