Dear student,
Barium hydrogen carbonate doesn't exists in solid state.
Bicarbonates of alkali metals are solid in state while bicarbonates of alkaline earth metals doesn't exists in solid state.
NaHCO3 , KHCO3 and RbHCO3 are ​bicarbonates of alkali metals so all are solid while ​Barium hydrogen carbonate is ​bicarbonate of group 2 element so doesn't exists in solid state.
Regards