Hydrothermal reaction of Zr(OPr)(4) with H3PO4 in the presence of ethylene diamine and HE yields three crystalline phases; the 1-D [enH(2)][Zr(HPO4)(3)], 1, which can grow as needles over 1 mm in length, the 2-D [enH(2)](0.5)[Zr(PO4)(HPO4)], 2, which is found as thin plates, and the previously reported fluorinated 3-D open-framework compound [enH(2)](0.5)[Zr-2(PO4)(2)(HPO4)F]. H2O, 3. The 1-D phase is the first of its type, with each Zr linked to neighboring metal atoms in the chain by three bridging phosphate groups via Zr-O-P-O-Zr linkages. Its crystals are monoclinic, space group C2/c, a = 8.996(3), b = 15.373(5), c = 9.582(4) Angstrom, beta = 102.97(2)degrees, V = 1287(1) Angstrom(3). Compound 2 is orthorhombic, space group Pnnm, a = 24.087(4), b = 5.381(1), c = 6.660(1) Angstrom, V = 863.0(4) Angstrom(3). It is related to the 'double layer' sheet compound gamma-ZrP and its ion exchanged analogues. (C) 1998 Academic Press.