Wet chemical analysis and diffractometry were used to characterize La1-xSrxMnO3+, where x ranged from 0 to 0.5. One series of samples was calcined in air. These materials were hexagonal. Another series was prepared from the first series by calcination in a N atmosphere. These materials were orthorhombic when x was between 0 and 0.20. When x was greater than 0.20, they were hexagonal. In the first series,  decreased with increasing x-value up to 0.30, became almost equal to 0, and remained there for x-values above 0.30. In the case of the second series,  was close to 0 over the entire range. The changes in unit cell volume, as a function of x, were shown to be consistent with the compositions of the materials. The observed and calculated densities were consistent with the presence of cation vacancies.

I.G.K.Andersen, E.K.Andersen, P.Norby, E.Skou: Journal of Solid State Chemistry, 1994, 113[2], 320-6