Weak narrow absorption bands at about 1074 cm−1 for
SrCO3 and 1060 cm−1 for BaCO3, due to the symmetric stretching
vibrations, were also detected [4–6,11]. It is worth to note that these
vibrations were shifted from the higher wavenumbers for SrCO3 to
the lower ones for BaCO3, due to the covalent bonding of M2+
cations (M=Sr and Ba) and O2− anions in the [CO3]2− complexes—
the cause of changing the efficient masses of the oscillating atomic