Key points are not available for this paper at this time.
A new determination of the atomic structure of CaTiOa has been made. It is orthorhombic, with space group Pcmn; atomic coordinates are given. Synthetic crystals are identical with the majority of natural perovskite specimens. Two of the modes of twinning reported by Bowman from optical analysis have been confirmed by both X-ray and optical methods.
Kay et al. (Sun,) studied this question.