Table 1. Selected bond lengths (Å).

Sr1—O11	2.556 (2)
Sr1—O12	2.574 (3)
Sr1—O2i	2.581 (3)
Sr1—O6ii	2.598 (3)
Sr1—O13	2.618 (3)
Sr1—O2	2.660 (3)
Sr1—O13iii	2.688 (2)
Sr1—O1	2.751 (3)
Sr1—O5ii	2.816 (3)
Ni1—O4	2.020 (3)
Ni1—O7	2.024 (3)
Ni1—O5	2.026 (2)
Ni1—O1	2.032 (3)
Ni1—O9	2.038 (3)
Ni1—O10	2.064 (3)

Symmetry codes: (i) ; (ii) ; (iii) .