PrOI Structure: ABC_tP6_129_c_a_c-003
Other compounds with this structure
AcOBr, AcOCl, AmOBr, AmOCl, AsCaRb, AsCdK, AsMnCs, AsMnK, AsMnRb, BaFBr, BaFI, BaHBr, BaHI, BaMnGe, BiMgK, BiMnCs, BiMnRb, BiOBr, BiOCl, BiOI, BrFEu, BrFPb, BrFSr, BrHCa, BrHEu, BrHSr, BrNTh, BrNU, BrOEu, BrOLa, BrONd, BrOPr, BrOSm, BrOYb, CaCoSi, CaFCl, CaHCl, CaHI, CaMnGe, CaMnSi, CaMnSn, CaNiGe, CaRuSi, CeCoGe, CeCoSi, CeFS, CeFeSi, CeMnSi, CeOCl, CeOsSi, CeRuSi, CmOCl, CsMnP, CsMnSb, CsNaTe, EuOCl, EuOI, GdCoSi, GdFeSi, GdOGd, GdRuSi, HLiO, HoFeSi, HoOCl, KCdSb, KLiS, KMnP, KMnSb, LaClSi, LaCoGe, LaFS, LaFeSi, LaGeRu, LaOCl, LaOI, LaRuSi, MgMnGe, MnGeNd, NdClP, NdClSi, NdFeSi, NdOCl, NdOGe, NdRuSi, NpOI, NpOSe, PClPr, PClSm, PFeSm, PbFI, PrClSi, PrFeSi, PrOGe, PrRuFe, PrRuSi, RbCaSb, RbLiS, RbLiSe, RbMnP, RbMnSb, RbNaO, RuNdGe, SSuTl, SeCuTl, SeFeN, SiClTb, SiFeY, SiMnY, SmFeSi, SmOCl, SmRuGe, SmRuSi, SrMnGe, ThNCl, ThNI, ThOSe, ThOTe, TmOI, UNCl, UNI, UOSe, UOTe, YOCl, YbFeSi, YbHCl, ZrOS
- Matlockite ($E0_{1}$) and PrOI have the same AFLOW prototype label, ABC_tP6_c_a_c. They are generated by the same symmetry operations with different sets of parameters (
--params) specified in their corresponding CIF files. - Indeed, (Potapova, 1977) state that PrOI is a Matlockite structure, but both AFLOW and the ICSD agree that they are different enough to warrant listing them as separate prototypes.
- In both cases we have $z_{3} ≈ - z_{2}$. We somewhat arbitrarily assign structures with the min($z_{2}$,$z_{3}$) $<$ 0.199 to the PrOI structure and those with larger values to the Matlockite structure.
- Binary forms of Matlockite/PrOI occur when the species on the (2a) site is the same as one of the species on the (2c) sites. We assign these structures to the prototypes:
- Cu$_{2}$Sb ($C38$) for structures with c/a $<$ 2,
- UP$_{2}$ for structures with 2 $<$ c/a $<$ 3, and
- LaSe$_{1.85}$ for structures with c/a ≈ 4.
- (Potapova, 1977) give this structure in setting 1 of space group $P4/nmm$ #129. We shifted the origin to put it into our standard setting 2.
\[ \begin{array}{ccc}
\mathbf{a_{1}}&=&a \,\mathbf{\hat{x}}\\\mathbf{a_{2}}&=&a \,\mathbf{\hat{y}}\\\mathbf{a_{3}}&=&c \,\mathbf{\hat{z}}
\end{array}\]
Basis vectors
| Lattice coordinates | Cartesian coordinates | Wyckoff position | Atom type | |||
|---|---|---|---|---|---|---|
| $\mathbf{B_{1}}$ | = | $\frac{3}{4} \, \mathbf{a}_{1}+\frac{1}{4} \, \mathbf{a}_{2}$ | = | $\frac{3}{4}a \,\mathbf{\hat{x}}+\frac{1}{4}a \,\mathbf{\hat{y}}$ | (2a) | O I |
| $\mathbf{B_{2}}$ | = | $\frac{1}{4} \, \mathbf{a}_{1}+\frac{3}{4} \, \mathbf{a}_{2}$ | = | $\frac{1}{4}a \,\mathbf{\hat{x}}+\frac{3}{4}a \,\mathbf{\hat{y}}$ | (2a) | O I |
| $\mathbf{B_{3}}$ | = | $\frac{1}{4} \, \mathbf{a}_{1}+\frac{1}{4} \, \mathbf{a}_{2}+z_{2} \, \mathbf{a}_{3}$ | = | $\frac{1}{4}a \,\mathbf{\hat{x}}+\frac{1}{4}a \,\mathbf{\hat{y}}+c z_{2} \,\mathbf{\hat{z}}$ | (2c) | I I |
| $\mathbf{B_{4}}$ | = | $\frac{3}{4} \, \mathbf{a}_{1}+\frac{3}{4} \, \mathbf{a}_{2}- z_{2} \, \mathbf{a}_{3}$ | = | $\frac{3}{4}a \,\mathbf{\hat{x}}+\frac{3}{4}a \,\mathbf{\hat{y}}- c z_{2} \,\mathbf{\hat{z}}$ | (2c) | I I |
| $\mathbf{B_{5}}$ | = | $\frac{1}{4} \, \mathbf{a}_{1}+\frac{1}{4} \, \mathbf{a}_{2}+z_{3} \, \mathbf{a}_{3}$ | = | $\frac{1}{4}a \,\mathbf{\hat{x}}+\frac{1}{4}a \,\mathbf{\hat{y}}+c z_{3} \,\mathbf{\hat{z}}$ | (2c) | Pr I |
| $\mathbf{B_{6}}$ | = | $\frac{3}{4} \, \mathbf{a}_{1}+\frac{3}{4} \, \mathbf{a}_{2}- z_{3} \, \mathbf{a}_{3}$ | = | $\frac{3}{4}a \,\mathbf{\hat{x}}+\frac{3}{4}a \,\mathbf{\hat{y}}- c z_{3} \,\mathbf{\hat{z}}$ | (2c) | Pr I |
References
- O. G. Potapova, I. G. Vasil'eva, and S. V. Borisov, Crystal structure of praseodymium oxide iodide, J. Struct. Chem. 18, 459–462 (1977), doi:10.1007/BF00753092. Translated from Zhurnal Strukturnoi Khimii 18, 573 (1977).
Found in
- Inorganic Crystal Structure Database. Entry 200047 (PrOI).
First cited in
- N. Anderson, M. J. Mehl, H. Eckert, S. Divilov, X. Campilongo, S. Curtarolo, The AFLOW Library of Crystallographic Prototypes: Part 5. Submitted to Computational Materials Science (2026).
Geometry files
Prototype Generator
aflow --proto=ABC_tP6_129_c_a_c --params=$a,c/a,z_{2},z_{3}$