Usage patterns
臨時の〈物〉a temporary/extra ~ (bus, staff member, budget, etc.)
Because of the typhoon, extra buses were put into service.
臨時に〈動詞〉to do something on a temporary or special basis
Since we're short-staffed, we decided to hire people temporarily.
臨時〈会・国会・総会〉が開かれるan extraordinary session/meeting is held
An extraordinary meeting was held to discuss the important issue.