The sharp changes in c can also be rationalized via the larger ionic radius of Ba when compared to Sr. Under Ba-rich conditions (x < 0.5) Ba enters site 2, causing local distortions of the CdP 4 tetrahedra, including and increase in the the P1-Cd-P1 the Cd-P1-Cd bond angles (Table ). Such distortions of the layers are indicative of the structure accommodating a larger cation in site 2. These local distortions then lead to an overall increase in the global c unit cell parameter.