{"database":"biostudies-literature","file_versions":[],"scores":null,"additional":{"submitter":["Dolyniuk J"],"funding":["Basic Energy Sciences"],"pagination":["3650-3659"],"full_dataset_link":["https://www.ebi.ac.uk/biostudies/studies/S-EPMC5437377"],"repository":["biostudies-literature"],"omics_type":["Unknown"],"volume":["8(5)"],"pubmed_abstract":["Order-disorder-order phase transitions in the clathrate-I Ba<sub>8</sub>Cu<sub>16</sub>P<sub>30</sub> were induced and controlled by aliovalent substitutions of Zn into the framework. Unaltered Ba<sub>8</sub>Cu<sub>16</sub>P<sub>30</sub> crystallizes in an ordered orthorhombic (<i>Pbcn</i>) clathrate-I superstructure that maintains complete segregation of metal and phosphorus atoms over 23 different crystallographic positions in the clathrate framework. The driving force for the formation of this <i>Pbcn</i> superstructure is the avoidance of Cu-Cu bonds. This superstructure is preserved upon aliovalent substitution of Zn for Cu in Ba<sub>8</sub>Cu<sub>16-<i>x</i></sub> Zn <sub><i>x</i></sub> P<sub>30</sub> with 0 < <i>x</i> < 1.6 (10% Zn/M<sub>total</sub>), but vanishes at greater substitution concentrations. Higher Zn concentrations (up to 35% Zn/M<sub>total</sub>) resulted in the additional substitution of Zn for P in Ba<sub>8</sub>M<sub>16+<i>y</i></sub> P<sub>30-<i>y</i></sub> (M = Cu, Zn) with 0 ≤ <i>y</i> ≤ 1. This causes the formation of Cu-Zn bonds in the framework, leading to a collapse of the orthorhombic superstructure into the more common cubic subcell of clathrate-I (<i>Pm</i>3<i>n</i>). In the resulting cubic phases, each clathrate framework position is jointly occupied by three different elements: Cu, Zn, and P. Detailed structural characterization of the Ba-Cu-Zn-P clathrates-I <i>via</i> single crystal X-ray diffraction, joint synchrotron X-ray and neutron powder diffractions, pair distribution function analysis, electron diffraction and high-resolution electron microscopy, along with elemental analysis, indicates that local ordering is present in the cubic clathrate framework, suggesting the evolution of Cu-Zn bonds. For the compounds with the highest Zn content, a disorder-order transformation is detected due to the formation of another superstructure with trigonal symmetry and Cu-Zn bonds in the clathrate-I framework. It is shown that small changes in the composition, synthesis, and crystal structure have significant impacts on the structural and transport properties of Zn-substituted Ba<sub>8</sub>Cu<sub>16</sub>P<sub>30</sub>."],"journal":["Chemical science"],"pubmed_title":["Controlling superstructural ordering in the clathrate-I Ba<sub>8</sub>M<sub>16</sub>P<sub>30</sub> (M = Cu, Zn) through the formation of metal-metal bonds."],"pmcid":["PMC5437377"],"funding_grant_id":["DE-AC02-06CH11357","DE-SC0008931"],"pubmed_authors":["Dolyniuk J","Kovnir K","Lee K","Whitfield PS","Lebedev OI"],"additional_accession":[]},"is_claimable":false,"name":"Controlling superstructural ordering in the clathrate-I Ba<sub>8</sub>M<sub>16</sub>P<sub>30</sub> (M = Cu, Zn) through the formation of metal-metal bonds.","description":"Order-disorder-order phase transitions in the clathrate-I Ba<sub>8</sub>Cu<sub>16</sub>P<sub>30</sub> were induced and controlled by aliovalent substitutions of Zn into the framework. Unaltered Ba<sub>8</sub>Cu<sub>16</sub>P<sub>30</sub> crystallizes in an ordered orthorhombic (<i>Pbcn</i>) clathrate-I superstructure that maintains complete segregation of metal and phosphorus atoms over 23 different crystallographic positions in the clathrate framework. The driving force for the formation of this <i>Pbcn</i> superstructure is the avoidance of Cu-Cu bonds. This superstructure is preserved upon aliovalent substitution of Zn for Cu in Ba<sub>8</sub>Cu<sub>16-<i>x</i></sub> Zn <sub><i>x</i></sub> P<sub>30</sub> with 0 < <i>x</i> < 1.6 (10% Zn/M<sub>total</sub>), but vanishes at greater substitution concentrations. Higher Zn concentrations (up to 35% Zn/M<sub>total</sub>) resulted in the additional substitution of Zn for P in Ba<sub>8</sub>M<sub>16+<i>y</i></sub> P<sub>30-<i>y</i></sub> (M = Cu, Zn) with 0 ≤ <i>y</i> ≤ 1. This causes the formation of Cu-Zn bonds in the framework, leading to a collapse of the orthorhombic superstructure into the more common cubic subcell of clathrate-I (<i>Pm</i>3<i>n</i>). In the resulting cubic phases, each clathrate framework position is jointly occupied by three different elements: Cu, Zn, and P. Detailed structural characterization of the Ba-Cu-Zn-P clathrates-I <i>via</i> single crystal X-ray diffraction, joint synchrotron X-ray and neutron powder diffractions, pair distribution function analysis, electron diffraction and high-resolution electron microscopy, along with elemental analysis, indicates that local ordering is present in the cubic clathrate framework, suggesting the evolution of Cu-Zn bonds. For the compounds with the highest Zn content, a disorder-order transformation is detected due to the formation of another superstructure with trigonal symmetry and Cu-Zn bonds in the clathrate-I framework. It is shown that small changes in the composition, synthesis, and crystal structure have significant impacts on the structural and transport properties of Zn-substituted Ba<sub>8</sub>Cu<sub>16</sub>P<sub>30</sub>.","dates":{"release":"2017-01-01T00:00:00Z","publication":"2017 May","modification":"2026-05-05T20:28:54.107Z","creation":"2019-03-27T02:45:25Z"},"accession":"S-EPMC5437377","cross_references":{"pubmed":["28580103"],"doi":["10.1039/c7sc00354d"]}}