Structure determination from small crystals of two aluminophosphates CrAPO-14 and SAPO-43

Small single crystals, ca 10 5 μm 3 , of two alumino-phosphates have been used to determine their structures. Both compounds were synthesized with the aim of incorporating chromium into the framework, and for CrAPO-14 the X-ray diffraction results show that this has been achieved. For CrAPO-14, Al 3.96 Cr 0.04 (PO 4 ) 4 (OH)-C 3 H 10 N-H 2 O, data recorded on a Rigaku AFC-SR diffractometer (Cu Kα) and, independently, on an Enraf-Nonius FAST diffractometer (Mo Kα), showed the structure to be like that of GaPO-14 [Parise (1986). Acta Cryst. C42, 670-673]; aluminium atoms occupy four-, five- and six-coordinated sites, and 45% of the aluminium in the six-coordinate site is replaced by chromium