The bonding energetics in a variety of alkaline metal, alkoxides and phenoxides, MOR, was investigated based on the corresponding enthalpies of formation in the crystalline state determined by reaction-solution calorimetry. The results obtained at 298.15 K were as follows: Delta(f)H(m)(o)(MOR, cr)/kJ mol(-1) = 382.7+/-1.4 (LiOC(6)H(5)), 513.6+/-2.5 (NaO-nC(6)H(13)), 326.4+/-1.4 (NaOC(6)H(5)), 375.2+/-3.4 (KOCH(3)), 434.5+/-2.7 (KOC(2)H(5)), 467.1+/-5.2 (KO-nC(3)H(7)), 459.3+/-2.1 (KO-nC(4)H(9)), 464.6+/-5.7 (KO-tC(4)H(9)), 464.3+/-2.5 (KO-nC(6)H(13)), 333.3+/-3.1 (KOC(6)H(5)), 380.6+/-2.9 (RbOCH(3)), 434.1+/-2.9 (RbOC(2)H(5)), 345.3+/-2.9 (LiOC(6)H(5)), 379.1+/-3.0 (CsOCH(3)), 432.3+/-3.1 (CsOC(2)H(5)), 466.9+/-5.0 (CsO-nC(3)H(7)), 461.3+/-3.5 (CsO-nC(4)H(9)), 461.9+/-2.5 (CsO-tC(4)H(9)), 349.2+/-1.4 (CsOC(6)H(5)). These results together with revised Delta(f)H(m)(o)(MOR, cr) values from the literature, were used to derive a consistent set of lattice energies for the MOR compounds and discuss general trends in the structure-energetics relationship based on the Kapustinskii equation.

The enthalpies of formation of lithium, sodium, potassium and thallium cyclopentadienyls were determined by reaction-solution calorimetry as ∆ f H°[LiCp] = −76.5 ± 2.9 kJ/mol, ∆ f H°[NaCp] = −39.7 ± 2.5 kJ/mol, ∆ f H°[KCp] = −83.2 ± [a] 1587 3.2 kJ/mol, and ∆ f H°[TlCp] = +117.7 ± 1.9 kJ/mol. Using a previously developed model, the enthalpies of formation of RbCp and CsCp were estimated.

The enthalpies of formation of lithium, sodium, potassium and thallium cyclopentadienyls were determined by reaction-solution calorimetry as ∆ f H°[LiCp] = −76.5 ± 2.9 kJ/mol, ∆ f H°[NaCp] = −39.7 ± 2.5 kJ/mol, ∆ f H°[KCp] = −83.2 ±