Crystal structures and phase transition of the cyanospinel K2Hg(CN)4
Gerlach, P. N. ; Powell, B. M.
College Park, Md. : American Institute of Physics (AIP)
Published 1986
College Park, Md. : American Institute of Physics (AIP)
Published 1986
| ISSN: |
1089-7690
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| Source: |
AIP Digital Archive
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| Topics: |
Physics
Chemistry and Pharmacology
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| Notes: |
The crystal structures of the high temperature (paraelastic) and low temperature (ferroelastic) phases of the cyanospinel K2Hg(CN)4 have been determined by neutron powder diffraction. At 298 K the crystal has the spinel structure and the cyanide coordination is ordered in the sequence N–C–Hg–C–N. Below the phase transition (111 K) the structure is trigonal with space group R3¯c. At the transition Hg(CN)4 tetrahedra adjacent along [111] rotate in antiphase as rigid units by ≈7° and the K ion shifts by ≈0.1A(ring). The transition has an ordering wave vector q0≡{1/2 1/2 1/2}. Comparison is made with the structural characteristics of other cyanospinels and it is suggested that the transitions cannot be understood in terms of steric interactions but must be a dynamic effect.
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| Type of Medium: |
Electronic Resource
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| URL: |