3-Biphenyldiazonium, 2'-carboxy-6-hydroxy-tetrafluoroborate, .delta.-lactone 6H-Dibenzo[b,d]pyran-2-diazonium, 6-oxo-, tetrafluoroborate(1-) 73927-76-1 Dibenzo[b,d]pyran-1-diazonium, 6-oxo-, tetrafluoroborate(1-) NSC81313 WLN: T B666 HOVJ DNN &.B-F4 &14/19