Discovery of extended carbon dioxide carbonates Choong-Shik Yoo, Washington State University, DMR 0854618

Project Goal: Investigate new states and novel phenomena in extreme conditions.

Major findings in this year:

•Discovery of extended ionic carbonate phase (i-CO3) in Earth mantle conditions.

•Determined crystal structure of i-CO3 to be post-aragonite structure (P21212) recently discovered in CaCO3.

•Increase of ionic character in CO bonds at high pressure, unlike the predicted high stability of CO4-Td covalent bond to 1TPa.

•Strong geophysical implications to the presence of volatile CO2 and carbon species in deep mantle conditions.

Significance: These results were previously unpredicted calling attentions for new theories and have strong implications to geophysics, physics, chemistry and materials sciences.

Phase/chemical transformation diagram of CO2 (top), providing geophysical constraints for deep carbon species (bottom) (Published in Yoo et al.,

Angew. Chem. Int. Ed. 50, 11219 (2011))

Phase/chemical transformation diagram of CO2 (top), providing geophysical constraints for deep carbon species (bottom) (Published in Yoo et al.,

Angew. Chem. Int. Ed. 50, 11219 (2011))

i-CO2

CO2

CaCO3

CO2-V

High-pressure behaviors of simple binary mixtures Choong-Shik Yoo, Washington State University, DMR 0854618

Project Goal: Investigate interaction and phase/structural miscibility of simple binary mixtures under extreme conditions.

Major findings in this year:

•Studies several binary mixtures of D2 with N2, CO2, H2O, NH3 and CH4.

•Unusually high repulsive interactions resulting in high internal chemical pressure

•Proton exchange reactions in D2-H2O and D2-NH3 mixtures,

•Evidence for proton ordering of D2-H2O at 20-60 GPa, substantially lower than that of pure H2O.

•Novel incommensurate phase of (N2)12D2 formed in 9:1 N2:D2 mixtures/

•Evidence of interfacial reactions in CO2-D2 mixtures.

Significance: These results provide fundamental insights into high pressure chemistry such as repulsive interaction, phase miscibility, and internal chemical pressures

(Top) Crystal structure of (N2)12D2 formed in N2:D2 mixture (Kim and Yoo, J. Chem. Phys. 134,

04519 (2011)). (Bottom) Proton ordering in D2:H2O mixture between 25 and 50 GPa (Gus and Yoo, J. Chem. Phys. 135, 174508

(2011)).

(Top) Crystal structure of (N2)12D2 formed in N2:D2 mixture (Kim and Yoo, J. Chem. Phys. 134,

04519 (2011)). (Bottom) Proton ordering in D2:H2O mixture between 25 and 50 GPa (Gus and Yoo, J. Chem. Phys. 135, 174508

(2011)).

Establishing fundamental chemistry concepts:•Extended solids as novel molecular alloys•Bonding vs packing at high density•Structure/phase miscibility vs chemical decomposition/phase separation•Internal chemical pressureDeveloping new enabling technologies:•Dynamic-DAC, capable of precise controls of pressure and compression rates, enabling high-pressure kinetic studies.•Time-resolved x-ray diffraction probing structural and chemical evolutions associated with single event phenomena.Leveraging collaboration and education:•Establishing a new research partnership with the HPCAT/APS, LLNL(NIF), and LANL for time-resolved x-ray diffraction under dynamic loading using dynamic-DAC.•Providing six Ph.D. students and two PD’s with hands-on experience in synchrotron x-rays and high pressure technologies.

Developing fundamental concepts, technologies, collaborations for high-pressure chemistry

Choong-Shik Yoo, Washington State University, DMR 0854618

APS

NIF