"235U" . . . . . "Uranium 235" . . "Uranium-235" . . . . . . . . . . "which is" . . "Uranium-235 (²³⁵U)" . . "U235" . . "U-235" . . "Uranium-235" . . . . . "U" . . "²³⁵U" . . "isotope U-235" . . . . . . "235" . "²³⁵" . "uranium" . "-235 (²³⁵U)" . . . "U²³⁵" . . . "uranium-235" .