Interaction of tantalum, chromium, and phosphorus at 1070 K: Phase diagram and structural chemistry

• Published in: Journal of solid state chemistry Vol. 235; pp. 50 - 57
• Main Authors: Lomnytska, Ya, Babizhetskyy, V., Oliynyk, A., Toma, O., Dzevenko, M., Mar, A.
• Format: Journal Article
• Language: English
• Published: United States 01.03.2016
• Subjects: Analogue; CHROMIUM; CRYSTALS; Diffraction; Homogeneity; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; INTERACTIONS; MONOCLINIC LATTICES; NICKEL PHOSPHIDES; PHASE DIAGRAMS; Phase equilibria; PHOSPHORUS; POWDERS; SOLIDS; SPACE GROUPS; TANTALUM; Titanium; X RADIATION; X-RAY DIFFRACTION; X-rays
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/j.jssc.2015.12.010

Solid-state phase equilibria have been established in the Ta-Cr-P system in the region of 0-67 at% P at 1070 K through powder X-ray diffraction analysis. Mutual substitution of Ta and Cr in binary phosphides gives rise to significant homogeneity ranges in Ta sub(1.00-0.66)Cr sub(0-0.34)P (NbAs-type; a=3.332(3)-3.1366(3) Aa, c=11.386(4)-11.364(2) Aa), Ta sub(3.0-2.1)Cr sub(0-0.9)P (Ti sub(3)P-type, a=10.156(2)-9.9992(2) Aa, c=5.015(1)-4.956(2) Aa), and Cr sub(3.0-2.4)Ta sub(0-0.6)P (Ni sub(3)P-type, a=9.186(5)-9.217(4) Aa, c=4.557(3)-4.5911(3) Aa). A limited homogeneity range is found in the ternary phase Ta sub(1.0-0.8)Cr sub(1.0-1.2)P (TiNiSi-type, a=6.2344(5)-6.141(2) Aa, b=3.5034(3)-3.3769(6) Aa, c=7.3769(6)-7.357(2) Aa). The OsGe sub(2)-type structures (space group C2/m) of a new P-rich compound, Ta sub(0.92(2))Cr sub(0.08(2))P sub(2) (a=8.8586(3) Aa, b=3.2670(2) Aa, c=7.4871(2) Aa, beta =119.315(2) degree ) as well as of the Ti-containing analogue Ta sub(0.93(3))Ti sub(0.07(3))P sub(2) (a=8.8592(5) Aa, b=3.2663(3) Aa, c=7.4870(5) Aa, beta =119.309(2) degree ) were refined from powder X-ray diffraction data. Solid-state phase equilibria have been established in the Ta-Cr-P system in the region of 0-67 at% P at 1070 K through powder X-ray diffraction analysis. Mutual substitution of Ta and Cr in binary phosphides gives rise to significant homogeneity ranges in Ta sub(1.00-0.66)Cr sub(0-0.34)P, Ta sub(3.0-2.1)Cr sub(0-0.9)P, and Cr sub(3.0-2.4)Ta sub(0-0.6)P. A limited homogeneity range is found in the ternary phase Ta sub(1.0-0.8)Cr sub(1.0-1.2)P. The OsGe sub(2)-type structures of a new P-rich compound, Ta sub(0.92(2))Cr sub(0.08(2))P sub(2) as well as of the Ti-containing analogue Ta sub(0.93(3))Ti sub(0.07(3))P sub(2) were establish from powder X-ray diffraction data. No homogeneity ranges for binary compounds Cr sub(12)P sub(7), Cr sub(2)P, Ta sub(5)P sub(3) were detected.