Probing the structure, stability and hydrogen storage properties of calcium dodecahydro-closo-dodecaborate

XRD pattern of polycrystalline CaB12H12·3H2O and the Rietveld refinement result.. Structure of 3 with thermal ellipsoids at the 40% probability level.. Temperature Programmed Desorption

Probing the structure, stability and hydrogen storage properties of

calcium dodecahydro-closo-dodecaborate

Vitalie Stavila1*, Jae-Hyuk Her2,3, Wei Zhou2,3, Son-Jong Hwang4, Chul Kim4,

Leigh Anna M Ottley1, Terrence J Udovic2

1 Sandia National Laboratories, Livermore, CA 94551; Albuquerque, NM 87106

2 NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899

3 Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742

4 Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125

*E-mail: vnstavi@sandia.gov

Figure S1 The IR spectra of as-synthesized compounds 1 – 3.

Figure S2 1H-coupled and decoupled 11B NMR spectra of 1 in H2O

Figure S3 1H and 11B MAS NMR spectra of 1 before and after hydration

Figure S4 XRD pattern of polycrystalline CaB12H12·3H2O and the Rietveld refinement result

Figure S5 Structure of 3 with thermal ellipsoids at the 40% probability level.

Figure S6 Temperature Programmed Desorption of 1CaB12H12:1CaH2 upon heating to 670 K

Figure S7 EDX analysis of the products obtained upon heating to 870 K of CaB12H12 and (1:1)

CaB12H12:CaH2

Table S1 Crystallographic Data for 1, CaB12H12·3H2O, and 3

Table S2 Fractional coordinates of CaB12H12∙3H2O from powder X-ray diffraction

Table S3 Fractional coordinates of 3 from single-crystal X-ray diffraction.

Table S4 Selected bond lengths (Å) and angles (deg.) for 3.

Figure S1 The IR spectra of as-synthesized compounds 1 – 3 (vertical offset for clarity)

10 0 -10 -20 -30 -40

ppm

CaDB_11B_2

-15.6 ppm

1H dec

1H coupled CaB12H12

Figure S2 1H-coupled and decoupled 11B NMR spectra of 1 in H2O

Figure S3 1H and 11B MAS NMR spectra of 1 before and after hydration

15 10 5 0 -5 -10

ppm

1H MAS NMR CaDB_1H

1.3 ppm

After hydration

dehydrated

CaB12H12 r =13 kHz

4.5 ppm

50 40 30 20 10 0 -10 -20 -30 -40 -50 -60 -70 -80

ppm

11B MAS NMR

CaDB_11B_4

r =13 kHz

Dehydrated

CaB12H12

after hydration

Figure S4 XRD pattern of tri-hydrated, polycrystalline CaB12H12·3H2O and the Rietveld refinement result Black: raw data points Red: calculated profile Blue: difference curve (observed – calculated) on the same scale Vertical tick marks: allowed Bragg reflection positions After 2θ ≈ 30°, the additional pattern and difference curve are both presented with 5× magnification The arrow at ∼14° denotes the position of an additional Lorentzian impurity line attributed to the strongest reflection of remnant anhydrous CaB12H12 phase, which was included in the refinement

Figure S5 Structure of 3 with thermal ellipsoids at the 40% probability level.

Figure S6 Temperature Programmed Desorption for 1CaB12H12:1CaH2 upon heating to 670 K.

(B) Figure S7 EDX analysis of the products obtained upon heating to 870 K of CaB12H12 (A) and

CaB12H12:CaH2 (B).

Table S1 Crystallographic Data for 1, CaB12H12·3H2O, and 3

Table S2 Fractional coordinates of CaB12H12∙3H2O from powder X-ray diffraction.

Table S3 Fractional coordinates of 3 from single-crystal X-ray diffraction.

Table S4 Selected bond lengths (Å) and angles (deg.) for 3.