Carlos Saldarriaga

Synthesis and structure of a porous zinc vanadate, Zn3(VO4)2·3H2O

A zinc vanadate with the formula Zn3(VO4)2·3H2O was synthesized by hydrothermal reaction of a gel of composition [(CH3CO2)2Zn·2H2O] : 0.5V2O5: 0.4 [1,3-diaminepropane] : 1.5 NaOH : 114 H2O, held at 170°C for 24 hours. The structure was determined ab initio by means of the EXPO direct methods program and refined with GSAS. The pale yellow solid crystallizes in the hexagonal space group P-6 with a= 6.07877(8), c= 7.1827(2) Å. The structure consists of vanadium tetrahedra bonded to distorted octahedral zinc atoms to create one dimensional columnar passageways for molecules. Though occupied by water in the as synthesized form, the passages could host other small molecules.

Crystal structure a cobalt molybdate type φx: NaCo2OH(H2O)(MoO4)2

A cobalt molybdate with the formula NaCo2OH(H2O)(MoO4)2 was synthesized by hydrothermal reaction at 200°C in 3 days. The structure was determined from powder data by means of the EXPO direct methods program and refined with GSAS. The purple solid crystallizes in the monoclinic space group C2/m with a=9.3789(3), b=6.3330(1), c=7.6280(2) A, and β=115.833(2)a. Octahedral cobalt atoms, centered at 1/4b and 3/4b, share edges to create endless chains running parallel to the b axis. The chains are connected through molybdenum tetrahedra, which share two vertices with consecutive octahedra in one chain and extend the third vertex to an adjacent chain; the fourth vertex protrudes into the interlayer space. This arrangement repeats itself indefinitely in the ab plane to create a layered structure.

A zinc phosphate with laminar structure: (ZnPO4)4(H2PO4)2(C4N2H14)2

Abstract A zinc phosphate compound with composition (ZnPO4)4(H2PO4)2(C4N2H14)2 was synthesized by the hydrothermal reaction of zinc oxide and phosphoric acid in the presence of 1,4-diaminebutane. The crystal structure was solved from powder data and exhibits triclinic symmetry with a=8.6590(3) A, b=10.3467(3) A, c=8.3910(3) A, α=102.180(2)°, β=93.676(2)° and γ=88.203(2)°. The new organo-zincophosphate has sheets built from saw-type four member ring ladders, where ZnO4 and PO4 tetrahedrons alternate. Additional phosphate groups project into the interlayer voids where the protonated amine resides.

A zinc chromate of type ΦY : synthesis and structure

Abstract A zinc chromate with the formula (NH 4 OH) 3/2 (ZnCrO 4 ) 2 was synthesized by hydrothermal reaction at 100°C in 24 h. The structure was solved from powder data and refined with GSAS. The yellow solid crystallizes in the hexagonal space group R−3m with a =5.99634(7) A and c =21.5117(3) A. Two types of adjacent rows of zinc octahedra, one of which is full while its neighbor has a vacant site between successive octahedra, are linked through chromate groups which extend two vertices to consecutive edge sharing octahedra in one row and a third vertex which serves as bridge to the contiguous row. The fourth tetrahedral vertex protrudes into the interlayer space. This arrangement repeats itself indefinitely in the ab plane to create a layered structure.

Synthesis and characterisation of the layered zinc phosphate KZn2(PO4)(HPO4)

Abstract A layered potassium zinc phosphate compound with composition KZn 2 (PO 4 )(HPO 4 ) was synthesised by the hydrothermal reaction of zinc chloride and phosphoric acid in the presence of KOH and triethanolamine. The crystal structure of KZn 2 (PO 4 )(HPO 4 ) was reinvestigated and solved from single crystal data in order to complete an early crystallographic work. The material shows a sinusoidal laminar structure based on sheets built from three member ring units, with two vertex-sharing ZnO 4 tetrahedral neighbours and one PO 4 tetrahedron; a three-connected oxygen atom closes the ring. Dangling phosphate groups protrude into the interlayer spaces and neutralize the K + ions. KZn 2 (PO 4 )(HPO 4 ) was also characterized by SEM, TG/DTA, 31 P MAS NMR and chemical analysis.

Synthesis and crystallographic data of a new copper phosphate CuPO 4 H⋅0.5H 2 O

A new copper phosphate, CuPO 4 H⋅0.5H 2 O, was synthesized using a low temperature hydrothermal method and characterized by powder X-ray diffraction, thermogravimetric analysis, and chemical analysis. The material is monoclinic, space group P 2 1 / c , with a =10.6524(2), b =8.4730(2), c =9.2204(2), β=92.43(0), and V =831.47 A 3 .

Structural characterization of a porous zinc vanadate: Zn 3 (VO 4 ) 2 ⋅3H 2 O

A novel porous material of composition Zn 3 (VO 4 ) 2 ⋅3H 2 O was prepared hydrothermally. The solid crystallizes in the hexagonal space group P 6 , with a =6.078 77(8), c =7.1827(2) A, and V =229.857 A 3 .

Structural characterization of a new zinc phosphate: (ZnPO4)4(H3PO4)2(C4N2H14)2

A new zinc phosphate was synthesized by the hydrothermal reaction of zinc oxide and phosphoric acid in the presence of 1,4-diaminebutane. The formula of the product is (ZnPO 4 ) 4 (H 3 PO 4 ) 2 (C 4 N 2 H 14 ) 2 and crystallizes in the triclinic system with a =8.6590(3) A, b =10.3467(3) A, c =8.3910(3) A, α=102.180(2)°, β=93.676(2)°, and γ=88.203(2)°.