This is how Megatron puts Dark Energon in his spark chamber goes in Darkness Rising Part 2.
[On the Nemesis, Starscream and Megatron are with the Dark Energon meteor]
Starscream: I don't think you need to worry about further Autobot interference, master.
Megatron: Not with Optimus gone. And what evidence do you possess of this fact?
Starscream: I destroyed the mines, as you instructed.
Megatron: Optimus is not so easily destroyed. We have millennia worth of battles behind us to prove it!
Starscream: Maybe you should take a break, my Lord. I worry that too much contact with the Dark Energon might allow it's properties to adversely affect you.
Megatron: Or perhaps, Starscream, I have not permitted myself contact enough.
[Megatron rips a shard of Dark Energon from the meteor]
Starscream: Wait! Lord Megatron! No! Not your Spark chamber! You do not know what it will do!
[Megatron stabs the Dark Energon into his spark chamber and his eyes start glowing purple]