Let's say that we have a gaseous or liquidus compound (I don't know if elements or compounds make a difference, take this as a thought experiment), and we have a tungsten or steel block that's 5cm (or less, you choose) thick. Is there any physical method for that gas or liquid to pass through that thick heavy metal block (not by drilling etc.)?
This is for a science fiction setting, in which this gas or liquid needs to be "sealed" within a confined space for narrative reasons, but I want to understand whether this is at all possible through real-science.

--------------------

I'll assume that you mean a stationary situation, i.e., that you don't want the heavy metal block to move.

If the compound is a gas under normal conditions (temperature and pressure),
Given that the gas or liquid cannot pass through the block (and I hope this is a consensus opinion), there is a very long and complex chain of events to get it through. I'm starting at the top of the liquid and working my way down, hoping to find out what is the final answer.

1. Pressure difference across block
- if gas or liquid pressure on one side is greater than the other, the gas/liquid won't go