A synchrotron single crystal X-ray structure determination of (NH sub 4 ) sub 3 Mo sub 4 P sub 3 O sub 16 : A microporous molybdenum phosphate with Mo sub 4 O sub 4 sup 6+ cubes

Journal Article · Wed May 01 00:00:00 EDT 1991 · Journal of Solid State Chemistry; (United States)

DOI:https://doi.org/10.1016/0022-4596(91)90252-D· OSTI ID:7109865

King, Jr, H E; Mundi, L A; Strohmaier, K G; Haushalter, R C ^[1]

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1. Exxon Research and Engineering Co., Annandale, NJ (United States)

Reaction of MoO{sub 3}, Mo, (NH{sub 4}){sub 2}HPO{sub 4}, H{sub 3}PO{sub 4}, and H{sub 2}O in a mole ratio of 1.4:1:3.6:6:120 at 360C for 16 hr gives a nearly quantitative yield of black cubes of (NH{sub 4}){sub 3}Mo{sub 4}P{sub 3}O{sub 16} (1). The structure of (1) was solved from data collected on a 30{times}30{times}30 {mu}m{sup 3} crystal at the National Synchrotron Light Source at Brookhaven National Laboratory. The compound is cubic, space group P{ovr 4}3m, with a=7.736(2) {angstrom}, and was refined to residuals of R(R{sub w}) = 0.035(0.049). Phosphate (1) is isotypic with Cs{sub 3}Mo{sub 4}P{sub 3}O{sub 16} and is related to the iron arsenate mineral pharmacosiderite. Unlike the Cs{sup +} compound, (1) can be rendered microporous by thermal removal of the NH{sub 4}{sup +} cations to give ammonia with the charge compensating proton remaining behind the lattice. Water absorption isotherms show the reversible uptake of 5.6 wt% water, which corresponds to over 15 vol% void space in (1) after the NH{sub 3} removal. The framework consists of Mo{sub 4}O{sub 4}{sup 6+} cubes, with six Mo-Mo contacts of 2.570(4){angstrom}, joined together by (PO{sub 4}){sub 6/2} along (100) to form a 3-D network composed of tetramers of triply edge-sharing Mo-centered octahedra and phosphate groups alternating along all (100) directions. The windows and cavities in (1) are large enough that the NH{sub 4}{sup +} cations occupy several different positions in the unit cell.

• OSTI ID: 7109865
• Journal Information: Journal of Solid State Chemistry; (United States), Vol. 92:1; ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
MOLYBDOPHOSPHATES
CRYSTAL STRUCTURE
SORPTIVE PROPERTIES
AMMONIUM COMPOUNDS
CATIONS
CHEMICAL PREPARATION
CUBIC LATTICES
EXPERIMENTAL DATA
NSLS
POROUS MATERIALS
SYNCHROTRON RADIATION
WATER
X-RAY DIFFRACTION
ACCELERATORS
BREMSSTRAHLUNG
CHARGED PARTICLES
COHERENT SCATTERING
CRYSTAL LATTICES
CYCLIC ACCELERATORS
DATA
DIFFRACTION
ELECTROMAGNETIC RADIATION
HYDROGEN COMPOUNDS
INFORMATION
IONS
MATERIALS
MOLYBDENUM COMPOUNDS
NUMERICAL DATA
OXYGEN COMPOUNDS
PHOSPHATES
PHOSPHORUS COMPOUNDS
RADIATION SOURCES
RADIATIONS
REFRACTORY METAL COMPOUNDS
SCATTERING
SURFACE PROPERTIES
SYNCHROTRON RADIATION SOURCES
SYNCHROTRONS
SYNTHESIS
TRANSITION ELEMENT COMPOUNDS
400201* - Chemical & Physicochemical Properties
400101 - Activation
Nuclear Reaction
Radiometric & Radiochemical Procedures