Patent ID: 8492304

Claim:
A manufacturing method of making an iron oxide through an iron complex, comprising: a chelating step mixing a ferric chloride, first chelating agent and second chelating agent with a solvent to form an iron complex solution, wherein the first and second chelating agents are selected from a group consisting of ethylenediamine, 1,10-phenanthroline, 2,2′-Bipyridine, diethylenetriamine, triethylenetetraamine, phenanthroline, and bipyridine, and Fe 3 +ions of ferric chloride being reacted with the first and second chelating agent to form the iron complex; a drying step removing the solvent from the iron complex solution to obtain a dried iron complex; and a heat treatment step executing heat treatment for the dried iron complex to form iron oxide with molecular formula Fe 3 O 4 , wherein the heat treatment step is processed under a nitrogen atmosphere; wherein the iron complex is in the form of Fe[R 1 ] a [R 2 ] b [H 2 O] c 3+ , with the R 1 representing the first chelating agent and the R 2 representing the second chelating agent and being different from the first chelating agent, wherein an equation of (a ×the coordination number of R 1 )+(b×the coordination number of R 2 )+c=6 is held and a, b and c are not zero.