Jump to main content
Jump to site search

Issue 9, 2015
Previous Article Next Article

Manganese borohydride; synthesis and characterization

Author affiliations


Solvent-based synthesis and characterization of α-Mn(BH4)2 and a new nanoporous polymorph of manganese borohydride, γ-Mn(BH4)2, via a new solvate precursor, Mn(BH4)2·1/2S(CH3)2, is presented. Manganese chloride is reacted with lithium borohydride in a toluene/dimethylsulfide mixture at room temperature, which yields halide and solvent-free manganese borohydride after extraction with dimethylsulfide (DMS) and subsequent removal of residual solvent. This work constitutes the first example of establishing a successful, reproducible solvent-based synthesis route for a pure, crystalline, stable transition metal borohydride. The new polymorph, γ-Mn(BH4)2, is shown to be the manganese counterpart of the zeolite-like compound, γ-Mg(BH4)2 (cubic, a = 16.209(1) Å, space group Id[3 with combining macron]a). It is verified that large pores (diameter > 6.0 Å) exist in this structure. The solvate, Mn(BH4)2·1/2S(CH3)2, is subsequently shown to be the analogue of Mg(BH4)2·1/2S(CH3)2. As the structural analogies between Mg(BH4)2 and Mn(BH4)2 became evident a new polymorph of Mg(BH4)2 was identified and termed ζ-Mg(BH4)2. ζ-Mg(BH4)2 is the structural counterpart of α-Mn(BH4)2. All synthesis products are characterized employing synchrotron radiation-powder X-ray diffraction, infrared spectroscopy and thermogravimetric analysis in combination with mass spectroscopy. Thermal analysis reveals the decomposition of Mn(BH4)2 to occur at 160 °C, accompanied by a mass loss of 14.8 wt%. A small quantity of the desorbed gaseous species is identified as diborane (ρm(Mn(BH4)2) = 9.5 wt% H2), while the remaining majority is found to be hydrogen.

Graphical abstract: Manganese borohydride; synthesis and characterization

Back to tab navigation

Supplementary files

Article information

14 Nov 2014
11 Jan 2015
First published
12 Jan 2015

Dalton Trans., 2015,44, 3988-3996
Article type
Author version available

Manganese borohydride; synthesis and characterization

B. Richter, D. B. Ravnsbæk, N. Tumanov, Y. Filinchuk and T. R. Jensen, Dalton Trans., 2015, 44, 3988
DOI: 10.1039/C4DT03501A

Social activity

Search articles by author