Webbläsaren som du använder stöds inte av denna webbplats. Alla versioner av Internet Explorer stöds inte längre, av oss eller Microsoft (läs mer här: * https://www.microsoft.com/en-us/microsoft-365/windows/end-of-ie-support).

Var god och använd en modern webbläsare för att ta del av denna webbplats, som t.ex. nyaste versioner av Edge, Chrome, Firefox eller Safari osv.

Thermal Polymorphism and Decomposition of Y(BH4)(3)

In English

Författare

  • Dorthe B. Ravnsbaek
  • Yaroslav Filinchuk
  • Radovan Cerny
  • Morlen B. Ley
  • Dörthe Haase
  • Hans J. Jakobsen
  • Jorgen Skibsted
  • Torben R. Jensen

Summary, in English

The structure and thermal decomposition of Y(BH4)(3) is studied by in situ synchrotron radiation powder X-ray diffraction (SR-PXD), B-11 MAS NMR spectroscopy, and thermal analysis (thermogravimetric analysis/differential scanning calorimetry). The samples were prepared via a metathesis reaction between LiBH4 and YCl3 in different molar ratios mediated by ball milling. A new high temperature polymorph of Y(BH4)(3), denoted beta-Y(BH4)(3), is discovered besides the Y(BH4)(3) polymorph previously reported, denoted alpha-Y(BH4)(3). beta-Y(BH4)(3) has a cubic crystal structure and crystallizes with the space group symmetry Pm (3) over barm and a bisected a-axis, a = 5.4547(8) angstrom, as compared to alpha-Y(BH4)(3), a = 10.7445(4) angstrom (Pa (3) over bar). beta-Y(BH4)(3) crystallizes with a regular ReO3-type structure, hence the Y3+ cations form cubes with BH4 anions located on the edges. This arrangement is a regular variant of (he distorted Y3+ cube observed in alpha-Y(BH4)(3), which is similar to the high pressure phase of ReO3. The new phase, beta-Y(BH4)(3) is formed in small amounts during ball milling; however, larger amounts are formed under moderate hydrogen pressure via a phase transition from alpha- to beta-Y(BH4)(3), at similar to 180 degrees C. Upon further heating, beta-Y(BH4)(3) decomposes at similar to 190 degrees C to YH3, which transforms to YH2 at 270 degrees C. An unidentified compound is observed in the temperature range 215-280 degrees C, which may be a new Y B H containing decomposition product. The final decomposition product is YB4. These results show that boron remains in the solid phase when Y(BH4)(3) decomposes in a hydrogen atmosphere and that Y(BH4)(3) may store hydrogen reversibly.

Publiceringsår

2010

Språk

Engelska

Sidor

3801-3809

Publikation/Tidskrift/Serie

Inorganic Chemistry

Volym

49

Issue

8

Dokumenttyp

Artikel i tidskrift

Förlag

The American Chemical Society (ACS)

Ämne

  • Physical Sciences
  • Natural Sciences

Status

Published

ISBN/ISSN/Övrigt

  • ISSN: 1520-510X