The physical properties common to all these compounds form today a solid basis which remains a real challenge for the theoretical models.
(The physical properties common to all these compounds; form; T:today; a solid basis which remains a real challenge for the theoretical models) (a solid basis; remains; a real challenge for the theoretical models)
The physical properties common to all these compounds a solid basis
form remains
T:today a solid basis which remains a real challenge for the theoretical models
a real challenge for the theoretical models