title: Thermochromism, the Alexandrite effect, and dynamic Jahn-Teller distortions in Ho2Cu(TeO3)2(SO4)2.
abstract: A 3d-4f heterobimetallic material with mixed anions, Ho2Cu(TeO3)2(SO4)2, has been prepared under hydrothermal conditions. Ho2Cu(TeO3)2(SO4)2 exhibits both thermochromism and the Alexandrite effect. Variable temperature single crystal X-ray diffraction and UV-vis-NIR spectroscopy reveal that changes in the Cu(II) coordination geometry result in negative thermal expansion of axial Cu-O bonds that plays a role in the thermochromic transition of Ho2Cu(TeO3)2(SO4)2. Magnetic studies reveal an effective magnetic moment of 14.97 μB. which has a good agreement with the calculated value of 15.09 μB.
authors.affiliation: Department of Chemistry and Biochemistry, Florida State University , 95 Chieftan Way, 310 DLC, Tallahassee, Florida 32306, United States.
authors.forename: Jian
authors.initials: J
authors.lastname: Lin
authors.forename: Kariem
authors.initials: K
authors.lastname: Diefenbach
authors.forename: Justin N
authors.initials: JN
authors.lastname: Cross
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Babo
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Albrecht-Schmitt