In non-metallic solids w/ just atoms or ions (no molecules), are bonds (vibrations) and electronic transitions the sole cause of blackbody radiation?

Since there wouldn't be a conduction band filled with any electrons in a non-metallic solid made of just atoms or ions (no molecules), it's hard to imagine any other type of movement and dipole moment than the stretching bonds between the atoms, or ions, as the cause of blackbody radiation (specifically infrared) in such solids. (And, yes, I'm aware that electronic transitions contribute, as well, in the range of visible light.) If there is another cause for such solids, please help clarify. I've heard of there being oscillations in electron density in the valence band of non metals, but not sure how that works if the valance band is full.