Solid-state synthesis and characterization of low-melting

mixed-metal oxides

GERARDO P. RAMOS OTERO

PRINCIPAL INVESTIGATOR: DR. L. KOSCIELSKI

University of Puerto Rico at Cayey

Outline

Solid-state Chemistry Background

Solid-state Synthesis Methodology

Future Work Acknowledgements

Solid-state Chemistry Background

Solid-state Chemistry

Solid-state Synthesis High Temperature

Starting Materials (powders, granules, crystals)

Process

Bond Disruption (high temperatures)

Rearrangement

Reformation (cooling)

Solid-state Chemistry Background

Low melting mixed metal oxides Ternary Compounds

MxM’yOz

Oxides At least one oxygen atom and one other

element in its chemical formula Oxygen in the oxidation state of −2 Electrical conductivity and optical

transparency

Solid-state Chemistry Background

Low Melting Metals

Solid-state Synthesis Methodology

Synthesis Vessel Preparation

Silica Tubes

Loading of Reagents Silica Tubes

Atmosphere

Glove-box

Heating of Reactions Computer-controlled furnace

Heating Step

Plateau Step

Slow-cooling Step

Trial and Error Approach

Solid-state Synthesis Methodology

Structural Determination

X-ray Spectroscopy

Powders and Crystals

Elemental Composition

Stoichiometry

Product

Powder

Powder X-ray diffraction

Novel Compound

Reload into silica tubes with

crystallizing agent

Crystal

Single-crystal X-ray diffraction

Previously Synthesized

Crystal

Single-crystal X-ray diffraction

Solid-state Synthesis Methodology

Physical Properties Determination Depends on the compound

Resistivity

Magnetic Properties

Thermopower

Ternary low-melting mixed-metal oxides already created

Loaded Reactions Groups 14/14

Loaded Reactions Groups 14/15

Synthesize new ternary compounds that contain two metals and an oxygen atom using previous synthesis methodology.

2In2O3 + 3SnO2 In4Sn3O12 (Already

synthesized)

2Ga2O3 + 3GeO2 Ga4Ge3O12

Characterize these compounds structurally via powder and single-crystal X-ray diffraction methods.

Determine selected physical properties such as magnetic susceptibilities, conductivity, resistivity, and thermopower.

Future Work

1,400 oC, 10h

1,400 oC, 10h

Future Work

Synthesis Methodology: 1. M + M’2O3 at 226.85oC for 10d

2. M2O3 + M’O2 at 1000oC for 2-3h

Future Work

Method 1

Future Work

Method 2

Acknowledgments

University of Puerto Rico at Cayey

RISE Program (Research Initiative for Scientific Enhancement)

BRIC

III (Instituto de Investigaciones Interdisciplinarias)

Dr. L. Koscielski

Solid-state synthesis and characterization of low-melting

mixed-metal oxides

GERARDO P. RAMOS OTERO

PRINCIPAL INVESTIGATOR: DR. L. KOSCIELSKI

University of Puerto Rico at Cayey

Conductivity and Resistivity

X-ray Spectroscopy