Polycrystalline Zn1-xFexO (0 <= x <= 0.075) solid solutions with the wurtzite structure belonging to the class of diluted magnetic semiconductors were synthesized by the precursor method using mixed Zn1-xFex(HCOO)(2)center dot 2H(2)O formate as a precursor. As an example we show for samples with x = 0.025 and 0.05 that the room-temperature magnetic moment of Zn1-xFexO solid solutions increases regularly with the iron concentration. (C) 2015 Elsevier B.V. All rights reserved.