Shape coexistence in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mrow/><mml:mn>180</mml:mn></mml:msup></mml:math>Hg studied through the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>β</mml:mi></mml:math>decay of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mrow/><mml:mn>180</mml:mn></mml:msup></mml:math>Tl

The ${\ensuremath{\beta}}^{+}$/EC decay of ${}^{180}$Tl and excited states in the daughter nucleus ${}^{180}$Hg have been investigated at the CERN On-Line Isotope Mass Separator (ISOLDE) facility. Many new low-lying energy levels were observed in ${}^{180}$Hg, of which the most significant are the 0${}_{2}^{+}$ at 419.6 keV and the 2${}_{2}^{+}$ at 601.3 keV. The former is the bandhead of an excited band in ${}^{180}$Hg assumed originally to be of prolate nature. From the $\ensuremath{\beta}$ feeding to the different states in ${}^{180}$Hg, the ground-state spin of ${}^{180}$Tl was deduced to be (4${}^{\ensuremath{-}}$,5${}^{\ensuremath{-}}$).