(2011?Quzhou) Xiaohua used two different methods to light the iron wire when he did the experiment of iron wire burning in oxygen, and carried out the following experiment. (2011? Quzhou) Xiao Hua conducted the following experiment.
(1) The wire did not burn when it was in full contact with oxygen, which means that the temperature did not reach the ignition point of the wire. Therefore: the temperature of the wire fell below the ignition point.
(2) iron wire in oxygen combustion can produce a black solid triiron tetraoxide, chemical formula: Fe3O4. so fill in: Fe3O4.