What is the difference between an instrumental leader and an expressive leader?

Instrumental leaders are task-oriented, they find specific ways to help the group reach its goals. Doesn't matter if group members don't get along, as long as they reach their goal.

Expressive leaders are emotion-oriented, hey find ways to keep the group together and to maintain morale. Doesn't matter if the group doesn't reach its goal, as long as they stay together and stay morally clean.