Thallium ( I ) sulfate ( Tl2SO4 ) or thallous sulfate is the sulfate salt of thallium in the common +1 oxidation state , as indicated by the Roman numeral I . It is often referred to as simply thallium sulfate , but it is more correct to add the I to specify the oxidation state , given that thallium ( III ) sulfate also exists and has some laboratory uses .
The thallium is in its +1 oxidation state .