A simple method is presented which allows us to estimate the binding energies and bonding capabilities of exotic species formed by electrons, positrons, and protons, namely, the positronium atom (Ps) and the dipositronium (Ps(2)) and positronium hydride (PsH) molecules. These exotic species are in fact the simplest clusters formed by the aforementioned fundamental particles and antiparticles. The simple Bohr atom model for hydrogen is extended to calculate the binding energies and radii of atomic orbitals of the Ps atom, as well as its atomic and covalent sizes and electronegativity. Based on these properties, the bond lengths and bond energies, including the covalent and ionic contributions, of the Ps(2) and the PsH molecules can be estimated from the corresponding (known) values of the dihydrogen molecule (H-2) using a Huckel-like molecular orbital calculation.
