Table 1.

Binding energies (−ΔE, kJ·mol⁻¹), distances R (Å), and H–O–O angles (<, ^o) for complexes of C₃H₄O₂ with acids.

Complex	−ΔE	R(O···O)	R(O–H)	R(O···H)	<H–O…O
Isolated monomer C3H4O2	0.0	2.558	1.001	1.648	19.5
ts isolated a	−11.6 a	2.365	1.205	1.205	11.1
C3H4O2:LiH at C=O	75.6	2.572	0.995	1.677	20.6
at O–H	64.6	2.492	1.017	1.551	17.3
ts	59.6	2.360	1.171	1.235	11.5
C3H4O2:LiF at C=O	81.9	2.564	0.997	1.664	20.2
at O–H	72.7	2.496	1.015	1.557	17.4
ts	67.1	2.359	1.176	1.229	11.4
C3H4O2:BeH2 at C=O	82.4	2.566	0.992	1.704	23.0
at O–H	67.2	2.473	0.994	1.691	22.5
ts	64.0	2.356	1.156	1.256	12.9
C3H4O2:BeF2 at C=O	99.8	2.573	0.992	1.704	23.0
at O–H	80.9	2.457	1.029	1.514	18.2
ts	78.9	2.358	1.140	1.275	13.3

^a The transition structure is 11.6 kJ·mol⁻¹ less stable than the equilibrium C₃H₄O₂ structure.