New ternary germanides of the general compo sition ThM2Ge2
were found to exist in the systems Th-Cr-Ge, Th-Mn-Ge, Th-Fe -Ge,
Th-Co- Ge, Th-Ni- Ge and Th- Cu-Ge. The crystal structure analysis
by means of the x - ray powder diffraction method showed that
these compounds are isostructural with the compounds ThM2Si2
(M = Cr, Mn, Fe, Co, Ni and Cu), discdvered in this labo.ratory,,
The tetragonal unit cell contains two formula units. Space group
is !4/mmm. The atomic positions of thorium and the transition
metal are defined by special position 2(a) and 4(d), respectively,
while the variabl e 2arameter z determining the position 4(e) of
the germanium atoms was obtained by computing the ele ctroi;i.
density distribution along the c-axis

M. Sikirica

Z. Ban

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CCA-339 CR 0 AT IC A CHEMIC A ACT A 36 (1964) 151 546.289 :546.841 :546.28 Original Scientific Paper Thorium Transition Metals Ternary Germanides M. Sikirica* and Z. Ban* Institute »Ruder Boskovic«, Zagreb, Croatia, Yugoslavia Received July 11, 1964 New ternary germanides of the general composition ThM2Ge2 were found to exist in the systems Th-Cr-Ge, Th-Mn-Ge, Th-Fe-Ge, Th-Co-Ge, Th-Ni-Ge and Th-Cu-Ge. The crystal structure analysis by means of the x -ray powder diffraction method showed that these compounds are isostructural with the compounds ThM2Si2 (M = Cr, Mn, Fe, Co, Ni and Cu), discdvered in this labo.ratory,, The tetragonal unit cell contains two formula units. Space group is !4/mmm. The atomic positions of thorium and the transition metal are defined by special position 2(a) and 4(d), respectively, while the variable 2arameter z determining the position 4(e) of the germanium atoms was obtained by computing the electroi;i. density distribution along the c-axis. INTRODUCTION A great variety of very interesting and often new crystal structures found in the ternary intermetanic systems, together with .the ibrnad interest for s uch systems from the point of view of the practical aipplicatiioo, has put an ever increasing accent on the 1research :in this field. 'l'he silic~des aind gernnanides as well as carbides, nitrides etc., are of special mterest because of its per-spective use iin :nuclear-technology. Besides, these co:mp.ounds have inte-resting chemical and physical properties which deserve to be im.vestigated. In this ar.ticle some new ternary germanides of thol'lium. and transition metals of the first series are described. They were found to ·be isostructural with the previously discovered ThM2Si2 compounds1 • EXPERIME.NTAL Mate·rials The following components were used in the elemental form: thorium (Thorium pulver-Nuclearrein, Merok, Darmstadt), chromium (Chromium metal, purity not quoted, The Coleman & Bell Co., USA), iron (Ferrum reductum p.a., Chinoin, Bu-dapest), manganese (Manganese flakes, 99.9%, Light & Co.), cobalt (Cobalt sponge, standard purity, Johnson, Matthey & Co.), nickel (Carbonyl nickel. 99.8%, T. Schu-chardt & Co., Milnchen), copper (Kupfer gepulvert, elektrolytisch, Merck, Darm-stadt) and germanium (Germanium pss., Fluka A. G., Switzerland) . Chromium and manganese were chrushed and sieved through a 200 mesh standard sieve. Mixtures of the corresponding components were cold pressed in small prisms. A thin molybdenum wire was pressed into one end of the compacted mixture and served later for the suspension of the sample in the specially designed electron beam furnace.2 * Permanent address: Laboratory of General and Inorg;mic Chemistry, Faculty of Science, University of Zagreb. 152 M. SIKIRICA AND Z. BAN An exothermic reaction was initiated by raising slowly the electron em1ss10n current. Samples were then subjected to a thermal treatment at 9000C during 120 hours. This was performed in sealed quartz tubes containing purified ::irgon under !'educed pressure. Such treatment did not change the phase corr.position but usualy introduced an increased amount of thorium oxide. X-rny Examination X-ray powder diffraction records were obtained from the most homogeneous parts of the specimens by means of a recording Philips diffractomet'3r equipped with a Geiger counter tube, using filtered CuK radia tion. Inevitably present weak diffraction lines of thorium oxide were used as an internal standard for accurate measurements of lattice parameters. RESULTS With the exception o.f ThCr2Ge2 , all compounds were obtained ·1n the single •phase form, and showed no unidentified peaks .in the powder diffraction records. This ·indicates that the composition ,of monophase specimeins probably does not correspond to the ideal formula ThCr2Ge2 , which can be explained either iin terms of a defect structure or as the rdistr.ibution .of Cr and Ge being statistical .rather than 1in the rat.io 1:1. The indexing by means of Buinn charts and the analysi:s of the systematically absent reflections re.vealed that these compounds are of the same structure type as ThM2Si2 (M = Cr, Mn, Fe, Co, Ni and Cu), prepared in this laboratory. The dimensions of the tetra-gonal unit cells conta.ining two formula unit.s of ThM2Ge2 are presented in Table I. The atomic positions in the s.pace :group 14/mmm, are the same as TABLE I Unit Cell Dimensions of ThM2Ge2 a (A) c (A) ThCr2Ge2 (4.11) (10.83) ThMn2Ge2 4.084 ± 0.002 10.930 ± 0.004 ThFe2Ge2 4.098 ± 0.002 10.222 ± 0.004 ThC02Ge2 4.109 ± 0.002 9.934 ± 0.004 ThNi2Ge2 4.161 ± 0.002 9.677 ± 0.004 ThCu2Ge2 4.152 ± 0.002 10.140 ± 0.004 TABLE II lnteratomic Distances in ThMt Ge2 (Jl) M = Cr Mn Fe Co Ni Cu z = (0.37'1) 0.385 0.371 0.372 0.367 0.379 Th 2(a) 8M 4(d) (3.40) 3.411 3.276 3.223 3.191 3.271 8 Ge 4(e) (3 .22) 3.154 3.183 3.180 3.2l s 3.182 2 Ge 4(e) (4.05) 4.208 3.79~ 3.695 3.551 3.843 M 4(d) 4M 4(d) (2.91) 2.88s 2.89s 2.905 2.942 2.93a 4 Ge 4(e) (2.46) 2.519 2.393 2.385 2.36s 2..454 THORIUM - TRANSITION METALS TERNARY GERMANIDES 153 hkl 002 101 110 103 11 2 004 200 202 11 4 211 105 0 0 6} 213 204 220 116 222 301 215 107 310 2 0 6 } 303 312 224 008 314 321 305 217 118 226} 323 208 109} 400 316 402 411 325 330 307 0, 0, 1 0 413 332 404 228 TABLE III Diffractometer Data for ThNi2Ge2 0.0253 0.0407 0.0687 0.0914 0.0939 0.1016 0.1368 0.1625 0.1778 0.1927 0.2281 0.2384 0.2741 0.2966 0.3296 0.3427 0.3655 0.3679 0.3756 0..4058 0.4669 0.4742 0.5026 0.5428 0.5481 0.5711 0.6041 0.6397 coinc. 0.6798 0.0254 0.0407 0.0686 0.0914 0.0940 0.1015 0.1373 0.1627 Q.1702 0.1779 0.1927 0.2281} 0.2283 0.2384 0.2741 0.2966 0.2995 0.3147 0.3297 0.3506 0.3427 0.3651} 0.3654 0.3680 0.3755 0.4055 0.4440 0.4518 Q.4668 0.4818 0.4740 0.5022} 0.5025 0.5426 0.5474} 0.5483 0.5708 0.5736 0.5889 0.6039 0.6168 0.6188 0.6336 0.6396 0.6421 0.6496 0.6796 Io 18.3 73.3 69.6 190.6 171.1 22.0 90.4 12.2 26.9 58.6 97.8 17.1 30.5 33.0 53.8 15.9 30.5 48.8 9.8 9.8 12.2 9.8 30.5 22.0 12.2 28.1 19.5 22.0 . 8.0 17.1 I c 11.4 71.9 75.5 204.6 189.3 16.2 119.7 5.7 1.0 21.4 50.4 2.3} 100.4 17.5 38.0 41,9 2.4 3.4 41.2 2.1 13.6 4.5} 22.8 42.7 8.2 9.5 0.2 5.2 12.2 2.7 7.6 3.1} 30.3 26.4 3.9} 13.6 33.8 1.0 4.0 19.4 3.4 1.1 25.2 coinc. 12.0 4.7 24.7 those ascribed to 1the a1I1alogous series of silicides, i.e. 2Th in (a), 4M in (d) and 4Ge in (e)3• The correlation of :the observed and calculated relative intensities allows the possibility of the partially statistical distribution of smaller atoms over the points (d) and (e). The prolonged heat treatment as descriibed in the experimental part of this article, improved the agreement ·154 M. SIKIRICA AND Z. BAN TABLE IV Diffractometer Data for ThCr2Ge2 h k I 002 101 110 103} 004 112 200 114 2 0 21· 105 211} 006 2 1 3} 204 116 2 2 o} 107 2 2 2} 215 301 2 0 6} 008 310 3 0 3} 224 0.0203 0.0402 0.0703 0.0805 0.0905 0.1403 0.1618 0.1813 0.2215 0.2523 0.2824 0.3022 0.3235 0.3513 0.3620 0.0202 0.0403 0.0704 0.0808} 0.0809 0.0907 0.1407 0.1512 0.1609} 0.1615 0.1809} 0.1819 0.2214} 0.2216 0.2523 0.2814} 0.2828 0.3016} 0.3022 0.3216 0.3226} 0.3234 0.3517 0.3621} 0.3623 Io 28 ' 1 ' 18 30 100 76 22 45 5 28 11 10 25 10 5 16 between the observed intensities and those which were calculated for the assumed positions. Final decision can not be made because of the nearly equal scatter.ing powers of transition metals and germanium. The .possible tendency of transition metal atoms to paiiring, Which in this case is suggested by the less pronounced nonmetallic character of germanium, as compared to silicon, should not be neglected. The variable parameter z for the position (e) was obta.ined by computing the electron density distr.ibution along the c-axis by using an reflections reco:rided with the signs determined by the thorium atom. The Fourier series !! (x, y, z)x=o ,...., ~ F(hkl) cos2nlz were computed by means of Beevers-Lipson y=o strips. The resulting distr.iibution of the elec.tron density along the c-axis for all compounds ga:ve clearly .resolved maxima indicating the position of ger-manium atoms. Table II .gives the numerical values for the parameter z and the 1nterafomic distances. It can be noticed that the parameter z assumes the same values as in the structure of ThM2Si2 • Since it was not possible to deter,mine these values for ThFe2Si2 and ThC02Si2 .because .of the .unfavourable peak to background ratio, we may assume that the z-values for ThFe2Ge2 and ThC02Ge2 hold equally weH iin the former case. The comparison between the ·observed and the calculated d.ntensities for ThNi2Ge2 , together with the cor-responding values sin26 are given in Table III. The dafa for other compounds are 1isted in Tables IV-VIII. THORIUM - TRANSITION METALS TERNARY GERMAN IDES 155 TABLE V Diffractometer Data for ThMn2Ge2 h kl sin26 o sin2t9c Io 0 0 2 0.0200 0.0199 12 1 0 1 0.0406 0.0406 28 1 1 0 0.0712 0.0713 38 0 0 4 } 0.0805 0.0795} 85 1 0 3 0.0804 1 1 2 0.0911 0.0910 100 2 0 0 0.1424 0.1423 46 1 1 4 0.1506 1 0 5 0.1600 0.1597 50 2 0 2 0.1625 0.1621 8 0 0 6 0.1788 2 1 1 0.1828 0.1828 11 2 0 4 } 0.2226 0.2217} 73 2 1 3 0.2226 1 1 (i 0.2503 0.2499 19 1 0 7 0.2791 0.2789 5 2 2 0 0.2846 0.2846 22 2 1 5 } 0.3021 0.3020} 32 2 2 2 0.3044 0 0 8 0.3179 0.3178 7 2 0 6 0.3211 3 0 1 0.3251 3 1 0 0.3558 0.3557 9 2 2 4 0.3645 0.3640} 14 3 0 3 0.3648 3 l 2 0.3755 0.3756 22 1 1 8 0.3894 0.3890 5 2 1 7 0.4215 0.4212 3 3 1 4 0.4352 1 0 9 0.4378 3 0 5 0.4443 0.4443 9 2 0 8 0.4601 .0.4601 17 2 2 6 0.4634 3 2 1 0.4674 0.4673 3 0 0 10 0.4966 3 2 3 0.5068 0.5071 12 3 1 6 0.53,12 0.5345 12 3 0 7 0.5635 1 1 10} 4 0 0 0.5687 0.5678} 0.5692 10 2 1 9 0.5801 3 2 5 0.5865 0.5866 15 4 0 2 0.5890 2 2 8 0.6023 0.6024 10 4 1 1 0.6097 1 0 11 0.6370 2 0 10} 3 3 0 ·0.6395 0.6389} 0.6403 4 4 0 4 0.6488 0.6486 8 Preliminary results of the measurement of magnetic susceptibilities, using the Gouy method, indicate a very interesting dependence o.f magnetic mo-ments .on the transition metal atom. The general ,trend is very simila.r to that found in the series of the transition metal and rare earth i.ons4• We met 156 M. SIKIRICA AND Z. BAN TABLE VI Diffractometer Data for ThFe2Ge2 h k I 0 0 2 1 0 1 1 1 0 1 0 3 0 0 4 1 1 2 2 0 0 1 1 4 2 0 2 1 0 5 2 1 1 ' 0 0 6 2 1 3 2 0 4 1 1 f3 2 2 0 2 2 2 1 0 7 2 1 5 3 0 1 2 0 ti 3 1 0 0 0 8 3 0 3 2 2 4. 3 1 2 1 1 8 3 1 4 2 1 7 3 0 5 3 2 1 2 2 6 1 0 9 2 0 8 3 2 3 3 1 6 4 0 0 0.0226 0.0410 0.0707 0.0867 0.0910 0.0935 0.1413 0.1777 0.1824 0.2280 0.2324 0.2824 0.3056 0.3187 0.3463 0.3525 0.3692 0.3757 0.4348 0.4601 0.5054 0.5106 0.5578 0.5653 0.0227 0.0411 0.0708 0.0866 0.0910 0.0935 0.1415 0.1618 0.1643 0.1776 0.1823 0.2044 0.2277 0.2322 0.2751 0.2826 0.3053 0.3135 0.3186 0.3236 0.3457 0.3533 0.3634 0.3691 0.3735 0.3756 0.4341 0.4441 0.4549 0.4599 0.4649 0.4870 0.4952 0.5047 0.5104 0.5577 0.5653 TABLE VII Diffractometer Data for ThCo2Ge2 h k 1 0 0 2 1 0 1 1 1 0 1 0 3 1 1 2 0 0 4 2 0 0 2 0 2 1 1 4 2 1 1 1 0 5 0.0240 0.041 2 0.0704 0.0894 0.0946 0.0964 0.1405 0.1821 0.1856 0.02-11 0.0412 0.0704 0.0894 0.0945 0.0964 0.1408 0.1649 0.1665 0.1817 0.1857 Io 10 55 59 142 16 134 f.5 4 35 12 2 70 15 15 5 32 5 5 10 25 7 10 15 22 15 10 Io 26 76 72 200 186 22 102 20 46 THORIUM - TRANSITION METALS TERNARY GERMANIDES 157 h kl sin28 0 sin219c Io 0 0 6 0.216·1 2 1 3 0.2302 0.2293 98 2 0 4 0.2370 0.2363 18 2 2 0 0.2811 0.2811 32 1 1 6 0.2888 0.2867 38 2 2 2 0.3052 3 0 1 0.322:3 2 1 5 0.3259 0.3260 50 1 0 7 0.32!J7 3 1 0 0.3514 2 0 6 0.3570 3 0 3 0.3704 0.3704 20 3 1 2 0.3755 0.3755 40 2 2 4 0.37'73 0 0 8 0.3841 0.3848 20 3 1 4 0.4476 1 1 8 0.4550 3 2 1 0.4628 3 0 5 0.4665 0.4666 14 2 1 7 0.4703 3 2 3 0.5108 0.5109 34 1 0 9 0.5221 2 0 8 0.5253 0.5253 27 4 0 0 0.56:'.3 0.5622 15 3 1 6 0.5677 0.5678 26 4 1 1 0.60:H 3 2 5 0 . 60~17 0.6071 18 TABLE VIII Diffractometer Data for ThCu2Ge2 h k 1 sin219u sin2 Elc Io 0 0 2 0.0231 0.0231 22 1 0 1 0.0404 0.0403 38 1 1 0 0.0689 0.0689 39 1 0 3 0.0864 0.0865 140 1 1 2 } 0.0919 0.0920} 134 0 0 4 0.0925 2 0 0 0.1379 0..1379 48 2 0 2 } 0.1617 0.1610} 10 1 1 4 0.1612 2 1 1 } 0.1789 0.1779} 76 1 0 5 0.1789 0 0 6 0.2077 2 1 3 0.2242 0.2240 (i0 2 0 4 0.2297 0.2300 14 2 2 0 } 0.2763 0.2753} 4.2 1 1 6 0.2766 2 2 2 0.2984 3 0 1 } 0.3155} 2 1 5 0.3164 0.3163 44 1 0 7 0.3172 3 1 0 0.3445 0.3442 10 2 0 6 0.3455 0.3454 6 3 0 3 0.3617 0.3617 20 158 M. SIKIRICA AND Z. BAN h k 1 sin219o sin219c I o 3 1 2 0.3672 0.3672 34 2 2 4 } 0.3692 0.3677} 0 0 8 0.3693 34 3 1 4 } 0.4377 0.4365} 1:--1 8 0.4381 18 3 2 1 } 0.4532} 3 0 5 0.4543 0.4540 20 2 1 7 0.4548 2 2 6 0.4831 3 2 3 0.4991 0.4993 16 1 0 9 0.5016 0.5019 10 2 0 8 0.5068 0.5069 24 4 0 0 } 0.5517 0.5507} 3 1 6 0.5519 14 4 0 2 0.5737 0 0 10 0.5770 4 1 1 } 3 2 5 0.5911 0.5908} 0.5917 18 3 0 7 0.5925 3 3 0 0.6195 4 1 3 0.6358 0.6370 14 2 1 9 0.6392 0.6396 14 3 3 2 0.6426 4 0 4 0,.6430 2 2 8 } 1 1 10 0.6448 0.6446} 0.6459 30 the vecy same behaviour, but with smaller absolute values of magnetic mo-ments, for the isomorphous silicides. We hope that the anticipated study of temperature-dependent magnetic behavibur and neutron diffraction data will en able us to clarify the magnetic structure o.f these compounds. Acknowledgment. The authors are very grateful to Prof. D. Grdenic for his stimulating interest and advices during the structure determination. REFERENCES 1. Z. B a n and M.. S i k i r i c a, to be published. 2. B. Kamen a r, Z. B an, and l\/L D ad i c, Croat. Chem. Acta 31 (1959) 159. 3. I nternational Tables for X-ray Crystallography, Birmingham, 1952. 4. J. H. Van V 1 e ck, The Theory of Electric and Magnetic Susceptibilities, Oxford University Press, London, 1959, p . 243 and 285. IZVOD Ternarni germanidi torija s prelaznim metalima M. Sikirica i Z. Ban Nadeni su novi ternarni germanidi. Opea im je formula ThM2Ge2. Rendgenska strukturna analiza Debye-Scherrerovom metodom pokazala je da je to niz spojeva koji su izostrukturni s ranije otkrivenim ternarnim silicidima analognoga sastava. Varijabilni parametar, koji definira polofaj atoma germanija u elementarnoj celiji, odreden je racunanjem raspodjele elektronske gustoce uzduz osi c. INSTITUT »RUDER BOSKOVIC« ZAGREB Primljeno 11. srpnja 1964. 

Thorium Transition Metals Ternary Germanides

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