Potassium under pressure: a pseudobinary ionic compound.
Experimentally, we have found that among the "complicated" phases of potassium at intermediate pressures is one which has the same space group as the double hexagonal-close-packed structure, although its atomic coordination is completely different. Calculations on this P6(3)/mmc (hP4) structure as a function of pressure show three isostructural transitions and three distinctive types of chemical bonding: free electron, ionic, and metallic. Interestingly, relationships between localized metallic structures and ionic compounds are found.
SUPA, School of Physics and Astronomy and Centre for Science at Extreme Conditions, The University of Edinburgh, Mayfield Road, Edinburgh, EH9 3JZ, United Kingdom.
M
M
Marqués
G J
GJ
Ackland
L F
LF
Lundegaard
G
G
Stinton
R J
RJ
Nelmes
M I
MI
McMahon
J
J
Contreras-García