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Diborides, LnB<sub>2</sub>, have been reported for Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu. All have the same, AlB<sub>2</sub>, [[yttrium borides#YB2 (yttrium diboride)|structure]] containing a graphitic layer of boron atoms. Low temperature ferromagnetic transitions for Tb, Dy, Ho and Er. TmB<sub>2</sub> is ferromagnetic at 7.2 K.<ref name = "Atwood"/>
Diborides, LnB<sub>2</sub>, have been reported for Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu. All have the same, AlB<sub>2</sub>, [[yttrium borides#YB2 (yttrium diboride)|structure]] containing a graphitic layer of boron atoms. Low temperature ferromagnetic transitions for Tb, Dy, Ho and Er. TmB<sub>2</sub> is ferromagnetic at 7.2 K.<ref name = "Atwood"/>



=== LnB<sub>4</sub> ===
=== LnB<sub>4</sub> ===

Revision as of 15:26, 21 April 2024

Lanthanide compounds are compounds formed by the 15 elements classed as lanthanides. The lanthanides are generally trivalent, although some, such as cerium and europium, are capable of forming compounds in other oxidation states.[1]

Hydrides

Chemical element La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
Atomic number 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
Metal lattice (RT) dhcp fcc dhcp dhcp dhcp r bcc hcp hcp hcp hcp hcp hcp hcp hcp
Dihydride[2] LaH2+x CeH2+x PrH2+x NdH2+x SmH2+x EuH2 o
"salt like"		 GdH2+x TbH2+x DyH2+x HoH2+x ErH2+x TmH2+x YbH2+x o, fcc
"salt like"		 LuH2+x
Structure CaF2 CaF2 CaF2 CaF2 CaF2 CaF2 *PbCl2[3] CaF2 CaF2 CaF2 CaF2 CaF2 CaF2 CaF2
metal sub lattice fcc fcc fcc fcc fcc fcc o fcc fcc fcc fcc fcc fcc o fcc fcc
Trihydride[2] LaH3−x CeH3−x PrH3−x NdH3−x SmH3−x EuH3−x[4] GdH3−x TbH3−x DyH3−x HoH3−x ErH3−x TmH3−x LuH3−x
metal sub lattice fcc fcc fcc hcp hcp hcp fcc hcp hcp hcp hcp hcp hcp hcp hcp
Trihydride properties
transparent insulators
(color where recorded) 		red bronze to grey[5] PrH3−x fcc NdH3−x hcp golden greenish[6] EuH3−x fcc GdH3−x hcp TbH3−x hcp DyH3−x hcp HoH3−x hcp ErH3−x hcp TmH3−x hcp LuH3−x hcp

Halides

Tetrahalides

Of the lanthanide tetrahalides, only the fluorides of cerium, praseodymium and terbium are well characterised. NdF4 and DyF4 have also been characterised.

Trihalides

Dihalides

Lower halides

Oxides

info about oxides

Monoxides

SmO EuO

Sesquioxides

All lanthanides form

Dioxides

CeO2 PrO2 TbO2

Other oxides

Pr-O Tb-O Ce-O?

Chalcogenides

Sulfides

Selenides

Tellurides

Hydroxides

basic info about hydroxides

Pnictides

Nitrides

Phosphides

Arsenides

Antimonides and bismuthides?

Carbides

maybe silicides but probably not

Borides

LnB2

Diborides, LnB2, have been reported for Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu. All have the same, AlB2, structure containing a graphitic layer of boron atoms. Low temperature ferromagnetic transitions for Tb, Dy, Ho and Er. TmB2 is ferromagnetic at 7.2 K.[8]

LnB4

Tetraborides, LnB4 have been reported for all of the lanthanides except EuB4, all have the same UB4 structure. The structure has a boron sub-lattice consists of chains of octahedral B6 clusters linked by boron atoms. The unit cell decreases in size successively from LaB4 to LuB4. The tetraborides of the lighter lanthanides melt with decomposition to LnB6.[13] Attempts to make EuB4 have failed.[14] The LnB4 are good conductors[15] and typically antiferromagnetic.[8]

LnB6

Hexaborides, LnB6 have been reported for all of the lanthanides. They all have the CaB6 structure, containing B6 clusters. They are non-stoichiometric due to cation defects. The hexaborides of the lighter lanthanides (La – Sm) melt without decomposition, EuB6 decomposes to boron and metal and the heavier lanthanides decompose to LnB4 with exception of YbB6 which decomposes forming YbB12. The stability has in part been correlated to differences in volatility between the lanthanide metals.[13] In EuB6 and YbB6 the metals have an oxidation state of +2 whereas in the rest of the lanthanide hexaborides it is +3. This rationalises the differences in conductivity, the extra electrons in the LnIII hexaborides entering conduction bands. EuB6 is a semiconductor and the rest are good conductors.[8][13] LaB6 and CeB6 are thermionic emitters, used, for example, in scanning electron microscopes.[16]

LnB12

Dodecaborides, LnB12, are formed by the heavier smaller lanthanides, but not by the lighter larger metals, La – Eu. With the exception YbB12 (where Yb takes an intermediate valence and is a Kondo insulator), the dodecaborides are all metallic compounds. They all have the UB12 structure containing a 3 dimensional framework of cubooctahedral B12 clusters.[15]

LnB66

The higher boride LnB66 is known for all lanthanide metals. The composition is approximate as the compounds are non-stoichiometric.[15] They all have similar complex structure with over 1600 atoms in the unit cell. The boron cubic sub lattice contains super icosahedra made up of a central B12 icosahedra surrounded by 12 others, B12(B12)12.[15] Other complex higher borides LnB50 (Tb, Dy, Ho Er Tm Lu) and LnB25 are known (Gd, Tb, Dy, Ho, Er) and these contain boron icosahedra in the boron framework.[15]

Organolanthanide compounds

Main article: Organolanthanide chemistry

stuff

See also

References

  1. ^ Some page from G&E
  2. ^ a b Fukai, Y. (2005). The Metal-Hydrogen System, Basic Bulk Properties, 2d edition. Springer. ISBN 978-3-540-00494-3.
  3. ^ Kohlmann, H.; Yvon, K. (2000). "The crystal structures of EuH2 and EuLiH3 by neutron powder diffraction". Journal of Alloys and Compounds. 299 (1–2): L16–L20. doi:10.1016/S0925-8388(99)00818-X.
  4. ^ Matsuoka, T.; Fujihisa, H.; Hirao, N.; Ohishi, Y.; Mitsui, T.; Masuda, R.; Seto, M.; Yoda, Y.; Shimizu, K.; Machida, A.; Aoki, K. (2011). "Structural and Valence Changes of Europium Hydride Induced by Application of High-Pressure H2". Physical Review Letters. 107 (2): 025501. Bibcode:2011PhRvL.107b5501M. doi:10.1103/PhysRevLett.107.025501. PMID 21797616.
  5. ^ Tellefsen, M.; Kaldis, E.; Jilek, E. (1985). "The phase diagram of the Ce-H2 system and the CeH2-CeH3 solid solutions". Journal of the Less Common Metals. 110 (1–2): 107–117. doi:10.1016/0022-5088(85)90311-X.
  6. ^ Kumar, Pushpendra; Philip, Rosen; Mor, G. K.; Malhotra, L. K. (2002). "Influence of Palladium Overlayer on Switching Behaviour of Samarium Hydride Thin Films". Japanese Journal of Applied Physics. 41 (Part 1, No. 10): 6023–6027. Bibcode:2002JaJAP..41.6023K. doi:10.1143/JJAP.41.6023. S2CID 96881388.
  7. ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. pp. 1230–1242. ISBN 978-0-08-037941-8.
  8. ^ a b c d David A. Atwood, ed. (19 February 2013). The Rare Earth Elements: Fundamentals and Applications (eBook). John Wiley & Sons. ISBN 9781118632635.
  9. ^ Wells, A. F. (1984). Structural Inorganic Chemistry (5th ed.). Oxford Science Publication. ISBN 978-0-19-855370-0.
  10. ^ Holleman, p. 1942
  11. ^ Perry, Dale L. (2011). Handbook of Inorganic Compounds, Second Edition. Boca Raton, Florida: CRC Press. p. 125. ISBN 978-1-43981462-8. Retrieved 17 February 2014.
  12. ^ Ryazanov, Mikhail; Kienle, Lorenz; Simon, Arndt; Mattausch, Hansjürgen (2006). "New Synthesis Route to and Physical Properties of Lanthanum Monoiodide†". Inorganic Chemistry. 45 (5): 2068–2074. doi:10.1021/ic051834r. PMID 16499368.
  13. ^ a b c Cite error: The named reference InorgReactvol13 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference Alper was invoked but never defined (see the help page).
  15. ^ a b c d e Cite error: The named reference Mori handbookvol38 was invoked but never defined (see the help page).
  16. ^ Reimer, Ludwig (1993). Image Formation in Low-voltage Scanning Electron Microscopy. SPIE Press. ISBN 978-0-8194-1206-5.

Category:Lanthanide compounds

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