Using an isoperibol twin Dewar solution calorimeter, the enthalpies of reaction of normal lead 2,4-dinitroresorcinol; monobasic lead 2,4-dinitroresorcinol; tribasic lead 2,4-dinitroresorcinol; quadrabasic lead 2,4-dinitroresorcinol; monobasic lead 4,6-dinitroresorcinol; dibasic lead 4,6-dinitroresorcinol and tribasic lead 4,6-dinitroresorcinol were determined as -29.36; -85.34; -179.12; -227.37; -96.62; -175.88 and -162.47 kJ mol - 1 , respectively, which, with various ancillary data, gave the standard enthalpies of formation of -396.01; -628.46; -1397.37; -1637.55; -927.74; -1132.95 and -1434.83 kJ mol - 1 , respectively.