  Several superconducting transition temperatures in the range of 30-40 K were
reported in the recently discovered intercalated FeSe sytem (A1-xFe2-ySe2, A =
K, Rb, Cs, Tl). Although the superconducting phases were not yet conclusively
decided, more than one magnetic phase with particular orders of iron vacancy
and/or potassium vacancy were identified, and some were argued to be the parent
phase. Here we show the discovery of the presence and ordering of iron vacancy
in nonintercalated FeSe (PbO-type tetragonal {\beta}-Fe1-xSe). Three types of
iron-vacancy order were found through analytical electron microscopy, and one
was identified to be nonsuperconducting and magnetic at low temperature. This
discovery suggests that the rich-phases found in A1-xFe2-ySe2 are not exclusive
in Fe-Se related superconductors. In addition, the magnetic {\beta}-Fe1-xSe
phases with particular iron-vacancy orders are more likely to be the parent
phase of FeSe superconducting system, instead of the previously assigned
{\beta}-Fe1+{\delta}Te.
