In the complex [Fe CN 6]4-, the central metal atom is iron Fe .Coordination number: The coordination number is the number of ligands in this case, cyanide ions, CN- attached to the central metal atom. In this complex, there are six cyanide ions attached to the iron atom, so the coordination number is 6.Geometry: With a coordination number of 6, the geometry of the complex is octahedral. In an octahedral geometry, the ligands are positioned at the vertices of an octahedron around the central metal atom.Oxidation state: To determine the oxidation state of the iron atom, we need to consider the charges of the ligands and the overall charge of the complex. Each cyanide ion CN- has a charge of -1. Since there are six cyanide ions, the total charge contributed by the ligands is -6. The overall charge of the complex is -4. Therefore, the oxidation state of the iron atom can be calculated as follows:Oxidation state of Fe + -6 = -4Oxidation state of Fe = -4 + 6Oxidation state of Fe = +2So, the oxidation state of the central metal atom iron in the complex [Fe CN 6]4- is +2.