Rahimi Mosafer Houri S, Paszkowicz Wojciech, Minikayev Roman, Fitch Andrew, Berkowski Marek
Institute of Physics, Polish Academy of Sciences, Al.Lotnikow 32/46, Warsaw, Poland.
European Synchrotron Radiation Facility, 71 avenue des Martyrs, Grenoble 38000, France.
Dalton Trans. 2024 Sep 18;53(36):15070-15082. doi: 10.1039/d4dt01850h.
Crystals of CaTM(VO) (TM = Co, Cu), belonging to the whitlockite family, were synthesized by solid-state reaction and studied as a function of the TM content () for the first time. The structure was refined at ambient conditions and at high temperatures up to 1200 K using the Rietveld method. The unit cell size significantly decreases with increasing TM content up to the solubility limit, , which is 0.78(3) for TM = Co and 0.75(4) for TM = Cu. Occupancy factors show a preference for the M5 site by Co/Cu. The unit cell size varies smoothly with temperature, while the axial ratio exhibits nonlinear behaviour above approximately 800 K. The thermal expansion coefficient was determined from 300-1100 K. Atomic arrangement modifications at higher temperatures are indicated by changes in the axial ratio, the thermal expansion coefficient, and the reduction of fractional TM occupancy at the M5 site at specific temperatures.
属于白磷钙铁矿族的CaTM(VO)（TM = Co、Cu）晶体通过固态反应合成，并首次作为TM含量（）的函数进行研究。使用Rietveld方法在环境条件和高达1200 K的高温下对结构进行了精修。直至溶解度极限，随着TM含量增加，晶胞尺寸显著减小，对于TM = Co，溶解度极限为0.78(3)，对于TM = Cu，溶解度极限为0.75(4)。占有率因子表明Co/Cu优先占据M5位点。晶胞尺寸随温度平滑变化，而轴比在约800 K以上呈现非线性行为。热膨胀系数是在300 - 1100 K范围内测定的。在特定温度下，轴比、热膨胀系数的变化以及M5位点处TM占有率分数的降低表明了高温下原子排列的改变。
