Exploration of the Crystal Structure and Thermal and Spectroscopic Properties of Monoclinic Praseodymium Sulfate Pr2(SO4)3

Yuriy G Denisenko; Victor V Atuchin; Maxim S Molokeev; Alexander E Sedykh; Nikolay A Khritokhin; Aleksandr S Aleksandrovsky; Aleksandr S Oreshonkov; Nikolai P Shestakov; Sergey V Adichtchev; Alexey M Pugachev; Elena I Sal'nikova; Oleg V Andreev; Illaria A Razumkova; Klaus Müller-Buschbaum

doi:10.3390/molecules27133966

Exploration of the Crystal Structure and Thermal and Spectroscopic Properties of Monoclinic Praseodymium Sulfate Pr₂(SO₄)₃

Molecules. 2022 Jun 21;27(13):3966. doi: 10.3390/molecules27133966.

Authors

Yuriy G Denisenko^{1

2

3}, Victor V Atuchin^{4

5

6

7

8}, Maxim S Molokeev^{9

10

11}, Alexander E Sedykh³, Nikolay A Khritokhin¹, Aleksandr S Aleksandrovsky^{12

13}, Aleksandr S Oreshonkov^{14

15}, Nikolai P Shestakov¹⁴, Sergey V Adichtchev¹⁶, Alexey M Pugachev¹⁶, Elena I Sal'nikova^{1

17}, Oleg V Andreev¹, Illaria A Razumkova¹, Klaus Müller-Buschbaum^{3

18}

Affiliations

¹ Department of Inorganic and Physical Chemistry, Tyumen State University, 625003 Tyumen, Russia.
² Department of General and Special Chemistry, Industrial University of Tyumen, 625000 Tyumen, Russia.
³ Institute of Inorganic and Analytical Chemistry, Justus-Liebig-University Giessen, 35392 Giessen, Germany.
⁴ Laboratory of Optical Materials and Structures, Institute of Semiconductor Physics, SB RAS, 630090 Novosibirsk, Russia.
⁵ Research and Development Department, Kemerovo State University, 650000 Kemerovo, Russia.
⁶ Department of Applied Physics, Novosibirsk State University, 630090 Novosibirsk, Russia.
⁷ Department of Industrial Machinery Design, Novosibirsk State Technical University, 630073 Novosibirsk, Russia.
⁸ R&D Center "Advanced Electronic Technologies", Tomsk State University, Tomsk 634034, Russia.
⁹ Laboratory of Crystal Physics, Kirensky Institute of Physics, Federal Research Center KSC SB RAS, 660036 Krasnoyarsk, Russia.
¹⁰ School of Engineering Physics and Radio Electronics, Siberian Federal University, 660041 Krasnoyarsk, Russia.
¹¹ Department of Physics, Far Eastern State Transport University, 680021 Khabarovsk, Russia.
¹² Laboratory of Coherent Optics, Kirensky Institute of Physics Federal Research Center KSC SB RAS, 660036 Krasnoyarsk, Russia.
¹³ Institute of Nanotechnology, Spectroscopy and Quantum Chemistry, Siberian Federal University, 660041 Krasnoyarsk, Russia.
¹⁴ Laboratory of Molecular Spectroscopy, Kirensky Institute of Physics Federal Research Center KSC SB RAS, 660036 Krasnoyarsk, Russia.
¹⁵ School of Engineering and Construction, Siberian Federal University, 660041 Krasnoyarsk, Russia.
¹⁶ Institute of Automation and Electrometry, Russian Academy of Sciences, 630090 Novosibirsk, Russia.
¹⁷ Research Department, Northern Trans-Ural Agricultural University, 625003 Tyumen, Russia.
¹⁸ Center for Materials Research (LaMa), Justus-Liebig-University Giessen, 35392 Giessen, Germany.

Abstract

Praseodymium sulfate was obtained by the precipitation method and the crystal structure was determined by Rietveld analysis. Pr₂(SO₄)₃ is crystallized in the monoclinic structure, space group C2/c, with cell parameters a = 21.6052 (4), b = 6.7237 (1) and c = 6.9777 (1) Å, β = 107.9148 (7)°, Z = 4, V = 964.48 (3) Å³ (T = 150 °C). The thermal expansion of Pr₂(SO₄)₃ is strongly anisotropic. As was obtained by XRD measurements, all cell parameters are increased on heating. However, due to a strong increase of the monoclinic angle β, there is a direction of negative thermal expansion. In the argon atmosphere, Pr₂(SO₄)₃ is stable in the temperature range of T = 30-870 °C. The kinetics of the thermal decomposition process of praseodymium sulfate octahydrate Pr₂(SO₄)₃·8H₂O was studied as well. The vibrational properties of Pr₂(SO₄)₃ were examined by Raman and Fourier-transform infrared absorption spectroscopy methods. The band gap structure of Pr₂(SO₄)₃ was evaluated by ab initio calculations, and it was found that the valence band top is dominated by the p electrons of oxygen ions, while the conduction band bottom is formed by the d electrons of Pr³⁺ ions. The exact position of ZPL is determined via PL and PLE spectra at 77 K to be at 481 nm, and that enabled a correct assignment of luminescent bands. The maximum luminescent band in Pr₂(SO₄)₃ belongs to the ³P₀ → ³F₂ transition at 640 nm.

Keywords: band structure; crystal structure; photoluminescence; praseodymium sulfate; thermal analysis; thermal expansion anisotropy; vibrational properties.

Grants and funding

21-19-00046/Russian Science Foundation