Unprecedented lattice volume expansion on doping stereochemically active Pb2+ into uniaxially strained structure of CaBa1−xPbxZn2Ga2O7

Abstract

Lone pair cations like Pb 2+ are extensively utilized to modify and tune physical properties, such as nonlinear optical property and ferroelectricity, of some specific structures owing to their preference to adopt a local distorted coordination environment. Here we report that the incorporation of Pb 2+ into the polar "114"-type structure of CaBaZn 2 Ga 2 O 7 leads to an unexpected cell volume expansion of CaBa 1-x Pb x Zn 2 Ga 2 O 7 (0 ≤ x ≤ 1), which is a unique structural phenomenon in solid state chemistry. Structure refinements against neutron diffraction and total scattering data and theoretical calculations demonstrate that the unusual evolution of the unit cell for CaBa 1-x Pb x Zn 2 Ga 2 O 7 is due to the combination of the high stereochemical activity of Pb 2+ with the extremely strained [Zn 2 Ga 2 O 7 ] 4− framework along the c-axis. The unprecedented cell volume expansion of the CaBa 1−x Pb x Zn 2 Ga 2 O 7 solid solution in fact is a macroscopic performance of the release of uniaxial strain along c-axis when Ba 2+ is replaced with smaller Pb 2+ .

Single-Step Synthesis of Fe-Doped Ni3S2/FeS2 Nanocomposites for Highly Efficient Oxygen Evolution Reaction

“…It can be clearly seen from Table that the lattice parameters ( a and c ) and the cell volume expand after the addition of FeCl 2 . This lattice volume expansion was caused by the substitution of Fe atoms into the Ni 3 S 2 host lattice . To further verify the structural property of the NSF- n catalysts, a Raman spectroscopy analysis was conducted using a green laser beam with an excitation wavelength of 532 nm.…”

“…This lattice volume expansion was caused by the substitution of Fe atoms into the Ni 3 S 2 host lattice. 22 To further verify the structural property of the NSF-n catalysts, a Raman spectroscopy analysis was conducted using a green laser beam with an excitation wavelength of 532 nm. It is clearly seen from Figure S2 that there are two additional peaks for all catalysts upon FeCl 2 addition as compared to the pristine Ni 3 S 2 .…”

Temperature-driven order–disorder structural transition in the oxygen sub-lattice and the complex superstructure of the high-temperature polymorph of CaSrZn2Ga2O7

“…The structural distortion of these oxides can be assessed using the distortion factor D = c / a , and an ideal closed packing will give the standard D value of 1.633. 36 The distortion factor for orthorhombic LT-(Sr 1− x Ca x )SrZn 2 Ga 2 O 7 was calculated using the equation D = c O /[( a O /√3 + b O )/2], where a O , b O , and c O are the cell dimensions. As shown in Fig.…”

First-Principles Calculations on Narrow-Band Gap d10 Metal Oxides for Photocatalytic H2 Production: Role of Unusual In2+ Cations in Band Engineering

“…The new VBM is made up of occupied Pb/Bi-6s orbitals or Sn-5s orbitals, which raise the VBM and narrows the band gap. 23,24 Given the strong covalent interaction between d 10 metal and oxygen atoms, the band gap value is still too big to absorb visible light. Therefore, the development of LP cation-based metal oxides with a narrow band gap and efficient carrier migration ability remains an ongoing challenge.…”

“…Beyond that, LP cations occasionally incorporate into the structural framework constructed by d 10 metal MO 4 (M = Ga, Zn, etc.) tetrahedrons, for example, CaPbZn 2 Ga 2 O 7 and Ca 2 PbGa 8 O 15 . , Given the strong covalent interaction between d 10 metal and oxygen atoms, the band gap value is still too big to absorb visible light. Therefore, the development of LP cation-based metal oxides with a narrow band gap and efficient carrier migration ability remains an ongoing challenge.…”