Work

High temperature polymorphic transition and crystal structures of feldspar-related SrZn 2 P 2 O 8

Year: 2025

Type: article

Abstract: Feldspars are among the most common phases in the Earth's crust and are characterized by wide variations in chemical composition and crystal structure motifs.In this paper, we synthesized SrZn 2 P 2 O 8 and studied it by means of scanning electron microscopy, electron microprobe analysis, powder X-ray diffraction at ambient and high-temperature (up to 900 ºC) conditions.We have structurally characterized for the first time layered triclinic β-modification of SrZn 2 P 2 O 8 (space group P ̅ , a = 5.0109(8), b = 8.6202(13), c = 9.7527(15) Å, α = 118.088(3),β = 74.622(6),γ = 87.525(6)°,V = 351.29(10)Å 3 ), which is structurally related to hexacelsian.The high-temperature study demonstrated that β-SrZn 2 P 2 O 8 irreversibly transformed into framework monoclinic paracelsian-like α-SrZn 2 P 2 O 8 (space group P2 1 /c, a = 8.3163(2), b = 9.5023(2), c = 9.0248(2) Å, β = 92.285(1)°,V = 712.60(1)Å 3 ) above 600 °C, which, in turn, is stable up to 900 °C, when it melts.Though the crystal structures of α-and β-modification of SrZn 2 P 2 O 8 are different (framework and layered, respectively), their thermal expansion is similar: α V ~ 26 ± 1 × 10 -6 °C -1 , α max / α min ~5.The possible occurrence of the corresponding minerals in nature is discussed.

Source: Mineralogical Magazine

DOI: 10.1180/mgm.2025.10187

Authors: Liudmila A. Gorelova, Maria G. Krzhizhanovskaya, Valentina A. Yukhno, Olga Yu. Shorets, Irina A. Volkova, Oleg S. Vereshchagin

Institutions: St Petersburg University, Institute of Chemistry of Silicates named after I.V. Grebenshchikov

Language: English

Topic: Crystal Structures and Properties

Subfield: Electronic, Optical and Magnetic Materials

Field: Materials Science

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,550

Funders: Saint Petersburg State University, Russian Science Foundation