Abstract High-purity powder samples of lithium and sodium azide (LiN3 , NaN3), cyanate (LiOCN, NaOCN) and hydrogen fluoride (LiFHF, NaFHF) were studied by means of 59.54 keV Compton spectroscopy. The measured isotropic Compton profiles were corrected for multiple scattering and transformed to spherically averaged reciprocal form factors Ba(s). The experimental results are compared with theoretical reciprocal form factors obtained from Hartree-Fock calculations with different types of basis sets (Gaussian-and Slater-type orbitals, with and without polarisation functions) both for the free ions and for several kinds of clusters. The importance of intraionic and interionic interaction for the description of chemical bonding in these compounds is pointed out and discussed.