| New vanadium phosphate, oxalatophosphate, and borophosphate compounds were synthesized and characterized by single crystal/powder X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, electron microscopy, and magnetic susceptibility measurements.; Ammonium/piperazinium vanadium phosphates, (NH4)VOPO 4·1.5H2O, (NH4)0.5VOPO 4·1.5H2O, (NH4)2[VO(H2 O)3]2-[VO(H2O)][(VO(PO4) 2]2·3H2O, (C4H12N 2)(H3O)[(VOPO4)4(H2O)H 2PO4]·3H2O and (C4H12N 2)[(VO)(VO2)2(H2O)(PO4) 2] were synthesized hydrothermally. Compounds (NH4)VOPO 4·1.5H2O and (NH4)0.5VOPO 4·1.5H2O have layered structures closely related to VOPO4·2H2O and A0.5VOPO4·xH 2O (A = mono- or divalent metals), and (C4H12N 2)(H3O)[(VOPO4)4(H2O)H 2PO4]·3H2O has an open-framework structure containing VOPO4 layers. The mixed valence vanadium atoms, V IV and VV in (NH4)0.5VOPO 4·1.5H2O and (C4H12N2)(H 3O)[(VOPO4)4(H2PO4]·3H 2O show charge ordering in the VOPO4 layers. (NH4) 2[VO(H2O)3]2[(VO(H2O)]-[(VO(PO 4)2]2·3H2O has an open-framework structure, whereas (C4H12N2)[(VO)-(VO 2)2(H2O)(PO4)2] has a layered structure containing discrete trinuclear [V3O13(H 2O)] corner-sharing units.; Vanadium oxalatophosphates, (A)n[VO(HPO4)] 2(C2O4)·xH2O (A = NH4, C2H10N2, CH6N3) have layered structures and contain both oxalate and phosphate anions coordinated to vanadium cations. Above ∼550°C, they undergo a topotactic transformation to (VO)2P2O7, an active and selective catalyst for the oxidation of butane to maleic anhydride via VOHPO4.; Several new vanadium borophosphates (C4H12N 2)6[(VO)2BP2O10]4·nH 2O, Na14[Na ⊃ {lcub}(VO)2BP2O10 {rcub}5]·nH2O and A17[A ⊃ {lcub}(VO) 2BP2O10{rcub}6]·nH2O (A = NH4+, K+, Rb+, Cs +) were synthesized hydro-thermally. They are formed by packing [(VO) 2BP2O10]n (n = 4, 5 and 6) cluster anions and counter cations. The most important difference between them is associated with the size of the encapsulated cations and the number of [V 2O8] and [BP2O10] building units. NH 4+, K+, Rb+ and Cs + cations are each accommodated in a six-ring formed by connecting 6[V2O8] and 6[BP2O10] units. A four-ring with no included cation is formed with the large... |
