The infrared spectra of phosphinic acid R2POOH dimers (R=CH3, CH2Cl, C6H5) have been studied in CCl4 and CH2Cl2 solutions (T=300 K). The infrared spectra of deuterated R2POOD dimers (R=CH3, CH2Cl) were also studied in the gas phase (T=400-550 K) and solid state (T=100-300 K). They are compared with previously studied spectra of the light (non-deuterated) dimers in the gas phase, in the solid state and in low-temperature argon matrices (T=12-30 K) in the 4000-400 cm-1 spectral region. It is found that the strong and broad ν(OH) dimer bands have similar shapes, nearly equal values of bandwidth and low-frequency shift, and possess the Hadzi ABC structure irrespective of the type of acid, significant differences of dimerization enthalpies, influence of solvent, the type of H-bonded complexes (cyclic dimers in the gas phase, in solutions, and in inert matrices, and infinite chains in the solid state), and temperature in the range 12-600 K. Isotopic ratio of the first moments of light and deuterated acid bands has