You can use HexChat on Windows, Mac, and Linux. You can use Textual on MacOS, which is nicer, but needs to be compiled from its source code to be used for free. Alternately, you can use the web client on any device, including mobile devices.
Host: chat.termer.net
Port: 6697
MAKE SURE TO USE SSL/TLS
Traditional connection string: chat.termer.net +6697
Host: ajx5lra4rvacgcrlsaqkh3eh57u6oi6dhbg3jvww5yphrxa4doq5jxid.onion
Port: 6667
Traditional connection string: ajx5lra4rvacgcrlsaqkh3eh57u6oi6dhbg3jvww5yphrxa4doq5jxid.onion 6667