chemical entity > molecular entity > transition element molecular entity > transition element coordination entity > iron coordination entity

... > chemical entity > molecular entity > polyatomic entity > heteroatomic molecular entity > coordination entity > transition element coordination entity > iron coordination entity

... > chemical entity > molecular entity > transition element molecular entity > iron group molecular entity > iron molecular entity > iron coordination entity

... > chemical entity > molecular entity > transition element molecular entity > d-block molecular entity > iron group molecular entity > iron molecular entity > iron coordination entity