1,4-Diazoniabicyclo[2.2.1]heptane, 1,4-bis(2-chloroethyl)-, salt with (R-(R*,R*))-2,3-dihydroxybutanedioic acid 1,4-Diazoniabicyclo[2.2.1]heptane, 1,4-bis(2-chloroethyl)-, salt with [R-(R*,R*)]-2,3-dihydroxybutanedioic acid (1:1) NSC261138