Crystal data and atomic arrangement are given for a new rare-earth cyc
lohexaphosphate decahydrate: Er2P6O18.10H(2)O. This compound is monocl
inic P2(1)/a, with a = 18.315(8), b = 13.343(4), c = 11.211(4)Angstrom
, b = 94.46(3)degrees, Z = 4, V = 2681(3) Angstrom(3). The crystal str
ucture was determined with a final R = 0.032 for 4897 independent refl
ections. It can be described as a succession of thick corrugated layer
s of alternated P6O18 rings and ErO8 polyhedra with wide channels wher
e non-bonded water molecules are located. The phosphoric ring anion ha
s no internal symmetry. The erbium polyhedra do not share any edge or
corner.