The　high　temperature　phase　of　Ta2O5　and　its　variants　were　maintained　in　a　pure　Ta2O5　specimen　using　the　conventional　solid-state　reaction　method　and　the　advanced　laser　irradiation　technique.　The　structure　of　the　high　temperature　phase　is　determined　to　be　tetragonal　with　lattice　parameters　of　a　=　3.86　angstrom　and　c　=　36.18　angstrom　and　space　group　of　I4(1)/amd.　Compared　to　the　previously　reported　crystal　structure,　the　number　of　the　total　basis　atoms　was　reduced　to　be　6　from　11.　The　modified　crystal　structure　interprets　well　the　recorded　high-resolution　electron　microscopy　images　and　the　selected　area　electron　diffraction　patterns.　Based　on　the　basic　tetragonal　structure,　the　crystal　lattice　structures　of　the　orthorhombic　and　monoclinic　variants　were　determined　and　the　corresponding　space　groups　were　analyzed　according　to　the　variation　of　the　symmetrical　elements.　In　addition,　crystal　atomic　structures　of　these　two　variants　were　proposed　based　on　the　tetragonal　structure.　(c)　2006　Acta　Materialia　Inc.　Published　by　Elsevier　Ltd.　All　rights　reserved.