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Professor John Evans' Outputs (104)

Mo2P4O15 - the most complex oxide structure solved by single crystal methods? (2004)
Journal Article
Lister, S., Evans, I., Howard, J., Coelho, A., & Evans, J. (2004). Mo2P4O15 - the most complex oxide structure solved by single crystal methods?. Chemical Communications, 2540-2541. https://doi.org/10.1039/B408413F

We report the crystal structure and phase transitions of Mo2P4O15 which, despite a simple chemical formula, has 441 crystallographically unique atoms in its asymmetric unit and thus has the most complex structure of any extended oxide reported to dat... Read More about Mo2P4O15 - the most complex oxide structure solved by single crystal methods?.

Application of the through-bond correlation NMR experiment to the characterization of crystalline and disordered phosphates (2004)
Journal Article
Fayon, F., King, I., Harris, R., Evans, J., & Massiot, D. (2004). Application of the through-bond correlation NMR experiment to the characterization of crystalline and disordered phosphates. Comptes rendus. Chimie, 7(3-4), 351-361

Through-bond correlation NMR experiments have been used to characterize the structure of MP2O7 crystalline compounds and disordered phosphates. For MP2O7 materials, the refocused INADEQUATE experiment allows discrimination between the possible space... Read More about Application of the through-bond correlation NMR experiment to the characterization of crystalline and disordered phosphates.

Structures and phase transitions of trigonal ZrMo2O8 and HfMo2O8 (2004)
Journal Article
Allen, S., Ward, R., Hampson, M., Gover, R., & Evans, J. (2004). Structures and phase transitions of trigonal ZrMo2O8 and HfMo2O8. Acta crystallographica. Section B, Structural science, 60, 32-40

This paper describes the structures, thermal-expansion properties and phase transitions of the trigonal forms of ZrMo2O8 and HfMo2O8. Both phases adopt a P(3) over bar m structure at room temperature and show positive thermal expansion. Both phases a... Read More about Structures and phase transitions of trigonal ZrMo2O8 and HfMo2O8.

Negative thermal expansion and oxygen disorder in cubic ZrMo2O8 (2003)
Journal Article
Allen, S., & Evans, J. (2003). Negative thermal expansion and oxygen disorder in cubic ZrMo2O8. Physical Review B, 68(13),

In this paper we report precise thermal expansion data for the cubic negative thermal expansion material gamma-ZrMo2O8 which has an average expansion coefficient of -6.9x10(-6) K-1 between 2 and 200 K and -5.0x10(-6) K-1 between 250 and 502 K. Therma... Read More about Negative thermal expansion and oxygen disorder in cubic ZrMo2O8.

alpha-Bi2Sn2O7 - a 176 atom crystal structure from powder diffraction data (2003)
Journal Article
Evans, I., Howard, J., & Evans, J. (2003). alpha-Bi2Sn2O7 - a 176 atom crystal structure from powder diffraction data. Journal of materials chemistry, 13(9), 2098-2103. https://doi.org/10.1039/b305211g

Pyrochlore-type bismuth tin oxide, Bi2Sn2O7, is a technologically important material used in applications such as catalysis and gas sensing. Its room temperature structure has been solved by a method of simulated annealing of combined X-ray and neutr... Read More about alpha-Bi2Sn2O7 - a 176 atom crystal structure from powder diffraction data.

Characterization of the room-temperature structure of SnP2O7 by P-31 through-space and through-bond NMR correlation spectroscopy (2003)
Journal Article
Fayon, F., King, I., Harris, R., Gover, R., Evans, J., & Massiot, D. (2003). Characterization of the room-temperature structure of SnP2O7 by P-31 through-space and through-bond NMR correlation spectroscopy. Chemistry of Materials, 15(11), 2234-2239

The room-temperature structure of SnP2O7 has been investigated using various one- and two-dimensional (1- and 2D) magic-angle spinning (MAS) NMR experiments. We show that P-31 homonuclear through-bond and through-space correlation NMR spectroscopies... Read More about Characterization of the room-temperature structure of SnP2O7 by P-31 through-space and through-bond NMR correlation spectroscopy.

Structural investigations of three triazines: solution-state NMR studies of internal rotation and structural information from solid-state NMR, plus a full structure determination from powder x-ray diffraction in one case (2003)
Journal Article
Birkett, H., Cherryman, J., Chippendale, A., Evans, J., Harris, R., James, M., …McPherson, G. (2003). Structural investigations of three triazines: solution-state NMR studies of internal rotation and structural information from solid-state NMR, plus a full structure determination from powder x-ray diffraction in one case. Magnetic Resonance in Chemistry, 41(5), 324-336

Three model 2,4,6-tris(amino)-1,3, 5-triazines, structurally related to a dyestuff molecule previously studied by NMR, were synthesized in order to enable the effects of rotamer exchange on the NMR spectra to be investigated in more detail. Two of th... Read More about Structural investigations of three triazines: solution-state NMR studies of internal rotation and structural information from solid-state NMR, plus a full structure determination from powder x-ray diffraction in one case.

An X-ray diffraction and MAS NMR study of the thermal expansion properties of calcined siliceous ferrierite (2003)
Journal Article
Bull, I., Lightfoot, P., Villaescusa, L., Bull, L., Gover, R., Evans, J., & Morris, R. (2003). An X-ray diffraction and MAS NMR study of the thermal expansion properties of calcined siliceous ferrierite. Journal of the American Chemical Society, 125(14), 4342-4349

Powder and single-crystal X-ray diffraction, combined with MAS NMR measurements, has been used to study the thermal expansion of siliceous zeolite ferrierite as it approaches a second-order displacive phase transition from a low-symmetry (Pnnm) to a... Read More about An X-ray diffraction and MAS NMR study of the thermal expansion properties of calcined siliceous ferrierite.

Variable temperature structural study of bismuth lead vanadate, BiPb₂VO₆ (2002)
Journal Article
Evans, I., Evans, J., & Howard, J. (2002). Variable temperature structural study of bismuth lead vanadate, BiPb₂VO₆. Journal of materials chemistry, 12(9), 2648-2652. https://doi.org/10.1039/b202648a

At room temperature, monoclinic BiPb2VO6 is a polar, noncentrosymmetric, second harmonic generation active material and its crystal structure is among the more complex to be solved ab initio from powder diffraction data. In its stability range, BiPb2... Read More about Variable temperature structural study of bismuth lead vanadate, BiPb₂VO₆.

Structure and phase transitions of SnP2O7 (2002)
Journal Article
Gover, R., Withers, N., Allen, S., Withers, R., & Evans, J. (2002). Structure and phase transitions of SnP2O7. Journal of Solid State Chemistry, 166(1), 42-48

SnP2O7 is a member of the ZrP2O7 family of materials, several of which show unusual thermal expansion behavior over certain temperature ranges and which show a number of displacive phase transitions on cooling from high temperature. Here we describe... Read More about Structure and phase transitions of SnP2O7.

Ferroelectric alignment of NLO chromophores in layered inorganic lattices: Structure of a stilbazolium metal-oxalate from powder diffraction data (2001)
Journal Article
Evans, J., Benard, S., & YuR. Clement, P. (2001). Ferroelectric alignment of NLO chromophores in layered inorganic lattices: Structure of a stilbazolium metal-oxalate from powder diffraction data. Chemistry of Materials, 13(11), 3813-+

The structure of the organic:inorganic layered material DAZOP[MnCr(ox)(3)](.)0 . 6CH(3)CN [DAZOP = 4-(4-dimethylamino- phenylazo)-1-methyl-pyridinium, which has 61 independent atoms in the asymmetric unit, has been solved from laboratory powder X-ray... Read More about Ferroelectric alignment of NLO chromophores in layered inorganic lattices: Structure of a stilbazolium metal-oxalate from powder diffraction data.

Pressure-induced cubic-to-orthorhombic phase transformation in the negative thermal expansion material HfW2O8 (2001)
Journal Article
Jorgensen, J., Hu, Z., Short, S., Sleight, A., & Evans, J. (2001). Pressure-induced cubic-to-orthorhombic phase transformation in the negative thermal expansion material HfW2O8. Journal of Applied Physics, 89(6), 3184-3188

The effect of pressure on the crystal structure of HfW2O8 has been investigated by neutron powder diffraction. At a hydrostatic pressure of 0.62 GPa at room temperature the cubic material transforms, with a 5% reduction in volume, to the same orthorh... Read More about Pressure-induced cubic-to-orthorhombic phase transformation in the negative thermal expansion material HfW2O8.

A new three-dimensional incommensurately modulated cubic phase (in ZrP2B7) and its symmetry characterization via temperature- dependent electron diffraction (2001)
Journal Article
Withers, R., Tabira, Y., Evans, J., King, I., & Sleight, A. (2001). A new three-dimensional incommensurately modulated cubic phase (in ZrP2B7) and its symmetry characterization via temperature- dependent electron diffraction. Journal of Solid State Chemistry, 157(1), 186-192

A detailed electron diffraction study has been made of the ZrP2O7 member of the AM(2)O(7) family of framework structures and of its temperature-dependent structural phase transformations. The room-temperature phase corresponds to a primitive 3 x 3 x... Read More about A new three-dimensional incommensurately modulated cubic phase (in ZrP2B7) and its symmetry characterization via temperature- dependent electron diffraction.

Ab initio structure determination of BiPb2VO6 from powder diffraction data
Journal Article
Evans, I., Howard, J., Withers, R., & Evans, J. (online). Ab initio structure determination of BiPb2VO6 from powder diffraction data. Chemical Communications, 1984-1985

The crystal structure of BiPb2VO6 has been determined from powder diffraction data using a combination of direct methods and the novel approach of applying simulated annealing methods simultaneously to X-ray and neutron data; BiPb2VO6 is a polar, non... Read More about Ab initio structure determination of BiPb2VO6 from powder diffraction data.

Synthesis and characterisation of the new oxyselenide Bi2YO4Cu2Se2
Journal Article
Evans, J., Brogden, E., Thompson, A., & Cordiner, R. (online). Synthesis and characterisation of the new oxyselenide Bi2YO4Cu2Se2. Chemical Communications, 912-913

In this communication we report the synthesis, structure and preliminary characterisation of Bi(2)LnO(4)Cu(2)Se(2) (Ln = Y, Gd, Sm, Nd, La) phases; these materials are members of a new family of layered oxychalcogenides.