Preparation and structure of manganese molybdates

Journal Article · Wed Dec 18 04:00:00 EST 1985 · Inorg. Chem.; (United States)

DOI:https://doi.org/10.1021/ic00220a035· OSTI ID:5979516

Clearfield, A; Moini, A; Rudolf, P R

Manganese molybdates were prepared by precipitation in aqueous solution. Several monohydrates were obtained in the pH range 3-8. A yellow precipitate that formed initially is also a monohydrate but transforms at 60-100/sup 0/C into other, more crystalline, products depending upon pH. The compound obtained at pH 7-8 is triclinic, with a = 5.776 (4) A, b = 5.964 (4) A, c = 6.992 (4) A, ..cap alpha.. = 100.32 (5)/sup 0/, ..beta.. = 95.56 (5)/sup 0/, ..gamma.. = 106.81 (5)/sup 0/, and Z = 2. The structure consists of molybdate tetrahedra and Mn(II) octahedra in which the tetrahedra share four corners with four different octahedra. The water molecule is coordinated to the manganese. Heating any of the hydrates to elevated temperatures converts them to the ..cap alpha..-MnMoO/sub 4/ phase. In contrast, hydrothermal treatment of the hydrates at 200/sup 0/C transforms them to an anhydrous product with the NiWO/sub 4/ structure. A compound, Na/sub 2/Mn/sub 2/(MoO/sub 4/)/sub 3/.3H/sub 2/O, was prepared from alkaline solution. Hydrothermal treatment at 200/sup 0/C converted it to NaMn/sub 2/(O-H)(H/sub 2/O)(MoO/sub 4/)/sub 2/. The structure of this latter phase confirmed the bridging scheme proposed earlier, as it was possible to locate the positrons of the hydrogen atoms. 22 references, 1 figure, 8 table.

• Research Organization: Texas A and M Univ., College Station
• OSTI ID: 5979516
• Journal Information: Inorg. Chem.; (United States), Journal Name: Inorg. Chem.; (United States) Vol. 24:26; ISSN INOCA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360201 -- Ceramics
Cermets
& Refractories-- Preparation & Fabrication
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
AQUEOUS SOLUTIONS
BOND LENGTHS
CHEMICAL PREPARATION
CRYSTAL STRUCTURE
DATA
DIMENSIONS
DISPERSIONS
ELEMENTS
EXPERIMENTAL DATA
HEATING
HIGH TEMPERATURE
HYDRATES
HYDROGEN
HYDROGEN COMPOUNDS
INFORMATION
LATTICE PARAMETERS
LENGTH
MANGANESE COMPOUNDS
MEDIUM TEMPERATURE
MIXTURES
MOLYBDATES
MOLYBDENUM COMPOUNDS
NONMETALS
NUMERICAL DATA
OXYGEN COMPOUNDS
PH VALUE
PHASE TRANSFORMATIONS
REFRACTORY METAL COMPOUNDS
SOLUTIONS
SPACE GROUPS
SYNTHESIS
TRANSITION ELEMENT COMPOUNDS
WATER