Call constants and volume per formula weight are tabulated for RE NiSn (RE = La to Lu, Y) and RE PdSn (RE = Nd to Ho). The unit cell constants are also plotted versus ionic radius of the RE; trends are noted. (DLC

Dwight, A. E.

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IICRYSTAL STRUCTURE OF R. E . NiSn AND R. E . PdSn EQUIATOMIC COMPOUNDS*A. E . DwightDepartment of Physics,Northern Ill inois UniversityDe Kalb, IL 60115CONP-830419—2°E83 009464DISCLAIMERThis report was prepared as an account of work sponsored by an agency of the United StatesGovernment. Neither the United States Government nor any agency thereof, nor any of theiremployees, makes any warranty, express or implied, or assumes any lega! liability or responsi-bility for the accuracy, completeness, or usefulness of any information, apparatus, product, orprocess disclosed, or represents that its use would not infringe privately owned rights. Refer-ence herein to any specific commercial product, process, or service by trade name, trademark,manufacturer, or otherwise does not necessarily .constitute or imply its endorsement, recom-mendation, or favoring by the United States Government or any agency thereof. The viewsand opinions of authors expressed herein do not necessarily state or reflect those of theUnited States Government or any agency thereof.March 1983The submitted manuscript t in been authoredby a contractor of the U. S. Governmentunder contract No. W-31-109-ENG-38.Accordingly, the U. S. Government retains anonexclusive, royalty-free license to publishor reproduce the published form of thiscontribution, or allow others to do to, lorU. S. Government purposes.NOTICEDistribution: PORTIONS OF THIS BEPOBT ARE ILLEGIBLE.1-3. M. F . Adams | t h a s b e s n reproduced from the best4. B. R. T. Frost available copy to permit the broadestI: 15: Sfekf **** «**"*7. H. R. Thresh£. Editorial Officemmmm OF ms mum isTo be presented at the 16th Rare Earth Research Conference, Tallahassee, FL,April 16-18, 1983. Accepted for publication in the proceedings which willbe published in a special issue of Journal of Less-Common Metals.XA portion of this work was performed at Argonne National Laboratory,Argonne, IL, under auspices of the U. S* Department of Energy.MASTER mmm OF T«JS MSUMERT IS UNUMITEDCrystal Structure tW H,K. NiSn ,-mcl U.K. PdSn llqui atomic CompoundsA. E. DwightDepartment of Physics, Northern Illinois University, DeKalb, IL 60115During an investigation of the Dy-Ni-Sn system a ternary compound DyNiSnwas found and identified as the TiNiSi-type. Isotypic compounds were foundin other R.E. NiSn and R.E. PdSn alloys.The alloys were made by arc melting as described in Ref. 1 and annealedto 800° C. Debye-Scherrer X-ray films were taken with filtered Co radiation.Unit cell constants were calculated from three high angle reflections, andindexing was verified with the aid of calculated intensities. The cellconstants and volume per formula weight (V/M) are given in Table I.Table I. Unit Cell Constants.oCompound a(A) b(A) c(A) V/M(A)3LaNiSnPrNiSnNdNiSnSmNiSnGdNiSnTbNiSnDyNiSnHoNiSnErNiSnTmNiSnYbNiSnLuNiSnYNiSnNdPdSnSoiFdSnGdPdSnTbPdSnDyPdSnHoPdSn7.7.7.7.7.7.7.7.7.7.6.6.7.7.7.7.7.7.7.636440395304199146112063016000983931154243232541821571174.4.4.4.4.4.4.4.4.4.4.4.4.4.4.4.4.4.4.661565415094644484394384254144264014496656396185985895817.5527.7067.697.687.6777.6617.6567.647.6297.6217.6167.6017.6657.9517.9297.9127.9167.8977.88467.265.464.663.261.6860.8760.4259.8459.2258.8758.85157.9660.6668.8567.3366.265.364.864.5(2)HoPdSn also occurs ' with the Fe2P-type structure, as do (Er, Tin,Lu, Sc) PdSn compounds.The unit cell constants aru jilottod against ionic radii of the rareoarths, in Kig. 1. Several trends arc noted:1. The a constant riser, with increasing ionic radius" moreosteeplv than do the b and c constants. This derives from the fact thatr • o oin the a direction the rare earth atoms form zig zag chains, withorelatively short interatomic distances. Substitution of a larger rare earth(e.g., Nd for Gd) causes enlargement of the unit cell, but mostly along therare earth chain.2. Substitution of Pd for Ni causes a large increase in the b Q andc constants, and only a slight increase in the a . The shortest Ni-Snand Pd-Sn interatomic distances are parallel to the b and C Q directions,and are dominated by the size of the Ni or Pd atom.3. The c of the R.E. NiSn series reaches a maximum value for PrNiSn,othen declines in LaNiSn. This is accompanied by an abnormal increase in b Qfor LaNiSn, which is the distance betxv-cen layers. This indicates that thepentagon which surrounds each R.E. atom has become stretched to its limit,and further increase in volume of the unit cell can only be accommodated byan increased separation of layers.A portion of this work was performed at Argonne National Laboratory underauspices ot the U.S. Department of Energy.References1. A. E. Dwight, in G. J. McCarthy et al (eds.), The Rare Earths in ModernScience and Technology, vol. 2, Plenum Press, 1980.2. A. E. Dwight, W. C. Harper and C. W. Kimball, J. Less-Common Met. 30(1971) 1.3. A. landelli and A. Palenzona, Chapter 13 in Handbook on the Physics andChemistry of Rare Earths, Vol. 2, K. A. Gschneidner and L. Eyring (eds.),North-Holland, 1979.8.07.8_ 7.61Ao7.04.64.4o RENiSn• REPdSn1 I 1 1 I II 1 I I ILuYbTmEr HoYOyTb Gd Smionic radiusNd Pr Ce LaFig. 1. Unit cell constants vs ionic radii for R.E. Ni(Pd)Sn compounds.

Crystal structure of R. E. NiSn and R. E. PdSn equiatomic compounds

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Crystal structure of R. E. NiSn and R. E. PdSn equiatomic compounds

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