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Article

Effects of Glymes on the Distribution of Mg(B10H10) and Mg(B12H12) from the Thermolysis of Mg(BH4)2

by
Ba L. Tran
1,
Tamara N. Allen
2,
Mark E. Bowden
1,
Tom Autrey
1,* and
Craig M. Jensen
2,*
1
Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA 99352, USA
2
Department of Chemistry, University of Hawaii at Manoa, 2545 McCarthy Mall, Honolulu, HI 96822, USA
*
Authors to whom correspondence should be addressed.
Inorganics 2021, 9(6), 41; https://doi.org/10.3390/inorganics9060041
Submission received: 17 April 2021 / Revised: 4 May 2021 / Accepted: 14 May 2021 / Published: 23 May 2021
(This article belongs to the Special Issue Metal Hydrogen Systems: Fundamental Properties and Current Applications for Energy Storage and Conversion)
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Versions Notes

Abstract

:
We examined the effects of concentrations and identities of various glymes, from monoglyme up to tetraglyme, on H2 release from the thermolysis of Mg(BH4)2 at 160–200 °C for 8 h. 11B NMR analysis shows major products of Mg(B10H10) and Mg(B12H12); however, their relative ratio is highly dependent both on the identity and concentration of the glyme to Mg(BH4)2. Selective formation of Mg(B10H10) was observed with an equivalent of monoglyme and 0.25 equivalent of tetraglyme. However, thermolysis of Mg(BH4)2 in the presence of stoichiometric or greater equivalent of glymes can lead to unselective formation of Mg(B10H10) and Mg(B12H12) products or inhibition of H2 release.

Graphical Abstract

1. Introduction

The safe storage of hydrogen in a compact and efficient form remains a formidable challenge towards the realization of energy decarbonization. Among the wide range of complex hydride materials studied, Mg(BH4)2 has garnered tremendous interest from the storage community because of desirable physical and thermodynamic properties [1,2,3,4]. Mg(BH4)2 features a high gravimetric density of H2 (ca. 14.7 wt% H2), and a thermodynamic range that is ideal for H2 release and H2 uptake at moderate pressure and temperature. Despite these attractive physical and thermodynamic properties, one major drawback of Mg(BH4)4 is the slow rate of H2 release at high temperature. To circumvent this high barrier towards reactivity, many studies have focused on generating complex mixtures of Mg(BH4)2 with additives composed of organic molecules [5,6,7,8,9], a different borohydride (e.g., LiBH4) [10,11,12], and transition metals [13,14,15,16] to lower the temperature for H2 release.
We have shown that the addition of a simple additive such as THF to Mg(BH4)2 can promote dehydrogenation of Mg(BH4)2 at temperature less than 200 °C compared to the dehydrogenation of solid Mg(BH4)2 at 250 °C and above [5,17]. Interestingly, in addition to lowering the dehydrogenation temperature, the presence of THF also favored the formation of B10H102− over B12H122− and B3H8- from Mg(BH4)2 compared to the favored formation of B3H8− over B10H102− and B12H122− for dehydrogenation of solid Mg(BH4)2 [17]. To our knowledge, the dehydrogenation of Mg(BH4)2 with triethylamine is the only system using an organic additive that favors the formation of B3H8- over B10H102− and B12H122− [5]. Unfortunately, a structure–activity relationship on the dehydrogenation of Mg(BH4)2 with THF is limited by structural derivatives. We therefore turned to glymes because of their abundance, availability, and more importantly broad structural derivatives to probe the dehydrogenation activity of Mg(BH4)2. Additionally, the combination of glymes and Mg(BH4)2 have also drawn interest as electrolytes for battery energy storage [18,19,20,21,22]. In addition, the thermodynamic affinity of the cation–glyme interaction is highly influenced by the number of chelating diether units, which may have some influence on Mg(BH4)2 dehydrogenation [23]. While structural studies of Mg(BH4)2 with monoglyme and diglyme are known [24,25], the effects of different glymes on the decomposition and product selectivity of Mg(BH4)2 have not been reported. Herein, we report the effects of a variety of glymes on the dehydrogenation of Mg(BH4)2 to form B10H102−, B12H122− and B3H8−.

2. Results

We initiated our studies by performing parallel reactions of Mg(BH4)2 with 1.0 equiv. of monoglyme (G1), triglyme (G3), and tetraglyme (G4) at 180 °C for 8 h (Table 1). The results of these reactions showed that G1, G3, and G4 contain the highest activity with conversion of Mg(BH4)2 in the rage of 33–50%. Conversely, diglyme (G2) showed minimal activity for the dehydrogenation of Mg(BH4)2 even at 200 °C for 8 h (Table 1, entry 13) with no apparent selectivity for any boron products. Like THF, G1 selectively produced B10H102− over B12H122− and B3H8− (Table 1, entry 1). While the conversion of Mg(BH4)2 is higher for G4 (50%) than that of G3 (39%), G3 has higher selectivity of forming B12H122− over B10H102− than that of G4 with a ratio of B12H122−/ B10H102− is 2.5/1.0 for G3 and 1.4/1.0 for G4 (Table 1, entry 2 vs. entry 3). This preference for B12H122− over B10H102− for the longer chain glymes in a 1:1 reaction with Mg(BH4)2 is the reverse of that of G1 and THF.
We have previously shown that only sub-stoichiometric amounts of THF additive are necessary for the dehydrogenation of Mg(BH4)2 [5]. Therefore, we analyzed the effect of sub-stoichiometric and excess quantities of G1 versus G4 on the product distribution of boron species. Since 1.0 equiv. of G1 to Mg(BH4)2 is selective for B10H102− formation, we investigated the effect of slight excess of G1 because a lowered equivalent of G1 is expected to favor B10H102− over B12H122− based on the result of sub-stoichiometric THF and 0.25 equiv. of G4 (Table 1, entry 6). Interestingly, at 1.5 equiv. of G1 to Mg(BH4)2, the formation of B10H102− remained favorable over B12H122−, but not selective because a 2.6:1.0 ratio of B10H102−: B12H122− was observed (Table 1, entry 4). Additionally, increasing to 26 equiv. of G1 to Mg(BH4)2 now favors forming B12H122− over B10H102− with a ratio of 1.9 to 1.0 (Table 1, entry 5). The results for the reaction of 0.25 equiv. of G4 to Mg(BH4)2 showed preference for B10H102− over B12H122− (Table 1, entry 6), which is in contrast to that of 1.0 equiv. of G4 to Mg(BH4)2 (Table 1, entry 3). Moreover, in the presence of excess G4, there was no dehydrogenative conversion of Mg(BH4)2 (Table 1, entry 7).
Lastly, as expected, increasing the temperature of the reactions also increased the rates of dehydrogenation of Mg(BH4)2. The reactions of 1.0 equiv. of G1, Me-THF, and G4 with Mg(BH4)2 at 200 °C for 8 h showed high conversion of Mg(BH4)2 (35–61%) compared to conversion at 160–180 °C (Table 1, entry 12, 14, 15). More importantly, increasing the temperature for the 1:1 reaction of G1, Me-THF, and G4 and Mg(BH4)2 does not alter the product selectivity between B10H102− and B12H122−. However, in case of G4, dehydrogenation at 200 °C leads to more side reactions of unknown boron products (16%). The 11B NMR data for the reactions of Mg(BH4)2 with 1.0 equiv. of G1 and G4 at 200 °C are presented in Figure 1. The results of these systematic studies clearly indicate the diverse and complex effects of varying the identity and the concentration of the glymes on product selectivity. It is potentially useful that the selective formation of B10H102− over B12H122− and vice versa can be controlled by using a single additive (e.g., G1) at different concentrations.
A working hypothesis for lowering the energy barrier for H2 release from Mg(BH4)2 involves the ability of the oxygen atom of THF to form a Mg-O coordinative interactions with the oxophilic Mg2+ ion. It is well-known that ortho-substituted THF binds weakly compared to THF to metal ions because the lone pairs on the oxygen atom are less exposed. To probe the effect of the relative binding strength of this Mg-O interaction on the dehydrogenation of Mg(BH4)2, we performed the 1:1 reaction of Mg(BH4)2 to Me-THF at 180 °C for 8 h (Table 1, entry 8). The result of the reaction showed minor conversion of Mg(BH4)2 (7%), yet the selective formation of B3H8- over B10H102− and B12H122− is similar to that of THF. However, at 200 °C, the conversion of Mg(BH4)2 showed significant improvement with conserved selectivity for B10H102− (Table 1, entry 15). To further demonstrate that only heteroatom-derived additives that can interact with the Mg2+ ion of Mg(BH4)2 or melt the Mg(BH4)2 upon heating can induce dehydrogenation, we performed the 1:1 reaction of Mg(BH4)2 and dodecane at 180–200 °C for 8 h and found no conversion of Mg(BH4)2 (Table 1, entry 9, 16). These two control studies suggest that the degree of interaction of Mg-O for THF and Me-THF might be critical for dehydrogenation activity and that nonpolar, high boiling, heteroatom-free hydrocarbons such as dodecane are not suitable to promote dehydrogenation of Mg(BH4).
The lack of H2 release from Mg(BH4)2 with dodecane is in stark contrast to the observation of H2 release in Et4NBH4 in decane–dodecane mixture at 185 °C for ~ 10 h [27]. Some interaction of the glyme with the Mg2+ center may be important for the dehydrogenation of Mg(BH4)2. It is also clear that some glyme is beneficial to the selectivity of B10H102− over B12H122−. However, excess G1 and G4 leads to complete loss of any selectivity for B10H102− or B12H122− and complete deactivation of H2 release from Mg(BH4)2. These results suggest the strong complexation of the Mg2+ center by excess glymes inhibits dehydrogenative activity by disfavoring the formation of Mg-H by potentially locking up the Mg2+ center of Mg(BH4)2. Moreover, the loss of B10H102− selectivity in the presence of excess G1 (Table 1, entry 5) to give a mixture of products, including favoring formation of B12H122− over B10H102−, also suggests that free G1 can interact with transient boron intermediates to drive different reaction pathways towards the formation of a variety of boron clusters.

3. Discussion

The complicated dependence of reaction conditions, pressure, and additives on the selectivity of B10H102− and B12H122− formation during the dehydrogenation of borohydride complexes have been previously observed [27,28,29,30]. Additionally, the unselective formation of B10H102− and B12H122− under varying reaction conditions suggests the factors controlling the reaction pathway to forming B10H102− and B12H122− are close in energy. Interestingly, kinetic studies on the thermolysis of Et4NBH4 in refluxing decane–dodecane mixture at 185 °C generating B9H92−, B10H102−, B11H14−, B12H122− as final products show that B3H8− is consumed over time with concomitant growth of B12H122− and B10H102− [27]. In fact, the relative rate of B3H8− consumption corresponds more closely with the faster rate of formation of B10H102− than that of the slower rate of formation of B12H122−, whereas the rate of B9H92− and B11H14− formation appears independent under this reaction temperature. In a separate study, heating Cs2B9H9 at 1 h at 600 °C was reported to give complete conversion to a mixture of B10H102− and B12H122− products [29]. However, the initial formation of B3H8− before forming B10H102− and B12H122− products has been observed for the thermolysis of solid Mg(BH4)2. Heating B2H6 and NaBH4 at 90 °C in diglyme leads to the formation of NaB3H8 suggesting that these B3H8− species can be generated at relative lower temperature. Thermolysis of NaB3H8 in diglyme at 162 °C leads to a mixture of products of Na2B6H6, Na2B10H10, and Na2B12H12 [31,32]. While there are kinetic and reaction data to support that B3H8− can readily form in the initial stages of constructing polyborane cages, it is unclear if the loss of B3H8− for the subsequent construction of larger polyboranes such as B10H102− and B12H122− is the direct result of construction from B3H8- or involves intermediate stages of B3H8− decomposition. For example, B3H8− may disproportionate to B2H4 and BH4-, and the reactive B2H4 go on to form the various polyborane products.
In the current reaction involving Mg(BH4)2, keeping track of the stoichiometry of the individual steps enables the development of a hypothesis to follow the chemical evolution. For example, the stoichiometry of the decomposition reaction of Mg(BH4)2 to Mg(B3H8)2 requires an accompanying production of MgH2 (Equation (1)):
3 Mg(BH4)2 → Mg(B3H8)2 + 2 MgH2 + 2H2
Titov has suggested that the initial step of decomposition of B3H8−, in the absence of MgH2 formed as a by-product in the reaction above, yields Mg(BH4)2 and a neutral reactive B2H4 species (Equation (2)) [31]
Mg(B3H8)2 → Mg(BH4)2 + 2[B2H4]
The neutral B2H4 can then decompose to form B2H6 and B5H9 (Equation (3))
6B2H4 → 2B5H9 + B2H6
In the decomposition of Mg(BH4)2 studied here, MgH2 is formed in concert with B3H8− opening additional pathways to compete with formation of B2H6 and B5H9. For example, in the presence of the MgH2, a diborane anion may be formed through reaction of B2H4 with MgH2 (Equation (4))
2MgH2 + 2[B2H4] → 2MgB2H6
The B2H62− has been proposed as an intermediate in the decomposition of Mg(BH4)2 on the pathway to forming B10H102− and B12H122− [33].
In a recent paper, Gigante et al. have compared the products observed in the decomposition of solvent free Mg(B3H8)2 in the presence and absence of MgH2 at 200 °C [34]. Indeed, they do report a difference in reaction products. In the absence of MgH2, volatile pentaborane and diborane were observed and substantial quantities of B10H102− and B12H122− were produced. In contrast, in the presence of MgH2, the reaction product was nearly all Mg(BH4)2, and substantially less pentaborane was observed in the gas phase. It is notable that, under the same reaction conditions, the presence of a two-fold stoichiometric excess MgH2 switched the reaction products between B10H102− and B12H122− and Mg(BH4)2. This result is consistent with B3H8- serving as a key intermediate connecting Mg(BH4)2 to B10H102− and B12H122−.
However, this does not explain the unique selectivity of B10H102− formation over B12H122− in the presence of G1, G4, THF, and MeTHF. At this time, we can only propose a hypothetical branching point that lowers the barrier of the pathway leading to the formation of B10H102−. One possible intermediate may be MgB10H12. Gaines and co-workers have shown that Na2B10H12 decomposes to form B10H10 in high yield in the presence of glyme [35]. However, in the presence of MeCN, the B10H122− decomposes to complex mixtures of boranes including both B9H92- and B10H102-. If B10H122− is a branching point, then the presence of glyme could reduce the barrier to form greater yields of B10H102−. However, this is supposition at this point and requires further study beyond the scope of the current work. Given the proposed role of MgH2 intermediates in the initial decomposition of Mg(BH4)2 and in the subsequent reactivity with transient boranes during dehydrogenation, the detection of MgH2 in the early stages of Mg(BH4)2 decomposition would provide key mechanistic evidence. The detection of MgH2 formation is difficult and remains an acknowledged issue in the field of H2 release from Mg(BH4)2 despite various efforts. However, MgH2 has been observed by in situ diffraction at 350–360 °C, but, in both cases, this was more than 50 °C higher than the initial release of H2 and constituted the formation of an amorphous intermediate [36,37].
Enhanced kinetics. In previous work, we have noted that the sub-stoichiometric adducts with THF induce a phase change from a polycrystalline Mg(BH4)2 compound to an amorphous phase at temperature below 100 °C [5,38]. We suggested that the diffusion rates of species in the amorphous phase will be enhanced, thus enhancing the rates of reaction. Therefore, a change in physical state enhances the rates of mass transfer and potentially increases the reactivity at lower temperatures compared to the neat bulk crystalline Mg(BH4)2. We offer another possibility involving the chemical nature of THF and Lewis base glyme adducts. It is well known that borane forms stable adducts with THF and other Lewis base adducts, e.g., dimethyl sulfide and amines. It is possible that the presence of catalytic (sub-stoichiometric) quantities of these adducts reduces the activation barrier for borohydride to form intermediates such as B2H7 and B3H8 anions (Equations (5) and (6)):
THF*MBH4 ⇔ [THF*BH3] + MH
[THF*BH3] + MBH4 ⇔ THF*MB2H7
In this role, the THF, or glyme, lowers the barrier to form B2H7 by stabilizing the BH3 transfer steps, i.e., [THF*BH3]. Glyme could perform a similar role as THF, thus the similar observations for enhanced reactivity, whereas the presence of a non-coordinating solvent, dodecane, shows no enhanced reactivity.
This does not directly explain the lack of reactivity in the experiments using diglyme (G2) or when excess tetraglyme (G4) is used. Recall that stoichiometric G4 showed enhanced reactivity, whereas an excess of G4 showed no dehydrogenation of BH4−. We propose that there is a competition between coordination of glyme and coordination of hydride and hydridoborate anions to Mg2+. Small quantities of glyme are effective in transferring transient BH3 as discussed above, but larger quantities introduce steric hindrance to the coordination of H−, B2H7−, B3H8−, etc. to Mg2+. We know that the THF or glyme coordinates to the Mg cation from X-ray crystal structures. The coordination of glymes to Mg2+ in solution has also been observed by NMR spectroscopy supported by ab initio calculations, which showed that the interaction increased with the glyme chain length [18]. Molecular dynamics simulations also showed differing arrangements of Mg2+ and BH4- when different glymes were present in excess [20]. G1 exhibited aggregate structures with larger numbers of Mg2+ and BH4- in relatively close proximity. G4, however, showed isolated Mg2+/BH4− contact ion pairs surrounded by coordinated glyme, which would make further coordination of hydride or larger hydridoborates more difficult.
Assuming these proposed hypotheses are correct, we can then start to suggest adducts that will enhance reactivity of H2 release from borohydrides by avoiding the too much of a good thing dilemma. The good news is that sub-stoichiometric amounts of additives will provide enhanced selectivity. A small amount of glyme can play the role of a catalyst, stabilizing the formation of borane and transferring borane to BH4 and subsequent borane clusters to release hydrogen at temperatures below 200 °C. The glyme further destabilizes the crystalline phase, enabling the phase transformation to an amorphous phase where mass transfer reactions will be enhanced, as such additives that bind ‘just right’ not too strong and not too weak would benefit the reactivity. Glyme and THF appear to be candidates to achieve this benefit. An excess of adduct or one that binds too strongly will prevent formation of MH because the metal has no available sites to transfer the hydride. Other challenges are to maintain the amorphous phase of the reaction throughout hydrogen release. As the borohydride is consumed, the intermediates and products may form a less mobile phase and mass transfer rates becomes slower as barriers for diffusion increase.

4. Materials and Methods

4.1. General Considerations.

95% Mg(BH4)2 was purchased from Sigma Aldrich (St. Louis, MO, USA), stored inside a nitrogen glovebox, and used as received. Monoglyme, diglyme, triglyme, tetraglyme, 2-methyltetrahydrofuran, and n-dodecane were stirred over CaH2 at 25 °C under N2 for at least 48 h before purification by vacuum distillation with heating as required. These additives were taken into a nitrogen glovebox and stored in oven-dried glass bottles and dried over activated 4 Å molecular sieves. The integrity of the solvents was verified by 1H NMR spectroscopy for purity before use. All sample preparation was conducted in a nitrogen glovebox.

4.2. General Procedure for Thermolysis Reaction of Mg(BH4)2 with Additives and 11B NMR Spectroscopy

The Mg(BH4)2 etherates were prepared by combining the equivalent amounts of each at room temperature, then thoroughly mixed with a spatula until reaching homogeneous consistency. The contents were then transferred to a 10 mL high-pressure stainless-steel Swagelok reactor, secured with a Swagelok valve. Reactors were placed in pre-heated aluminum block containing 6 wells. The aluminum block was further covered with 3–5 layers of aluminum foil. Temperatures of the heating block were monitored using a thermocouple and a thermometer for verification. After the allocated reaction time, the reactors were cooled in the glovebox antechamber, taken into the glovebox, and the boron products were transferred into a vial for characterization by 1H or 11B NMR spectroscopy on a Varian 500 MHz spectrometer with 11B chemical shifts were referenced to BF3∙Et2O (ẟ = 0 ppm) and 1H chemical shifts were referenced to TMS (ẟ = 0 ppm). A relaxation delay of 10 s was used for all 11B analyses with a 45° pulse. The boron samples were extracted into 2:1 ratio of D2O:THF. The calculation of percent composition of decomposition products was based on peak areas, and conversion is reported as the fraction of BH4− converted to other boron compounds.

5. Conclusions

We have shown that a variety of glymes can promote H2 release in the thermolysis of Mg(BH4)2 from 160–200 °C. 11B NMR analysis shows that boron clusters of B10H102− and B12H122− are the major products, in which the relative product distribution is strongly dependent on the identity and the concentration of the glyme employed in the thermolysis.

Supplementary Materials

The following are available online at https://www.mdpi.com/article/10.3390/inorganics9060041/s1, TGA and DSC data for Mg(BH4)2 with G1, G2, G3, and G4 (Figures S1–S4).

Author Contributions

T.N.A., B.L.T., T.A. and C.M.J. conceived and designed the experiments. T.N.A. and B.L.T. performed the experiments; T.N.A., B.L.T., M.E.B., T.A., and C.M.J. contributed to analyzing the data and writing the paper. All authors have read and agreed to the published version of the manuscript.

Funding

The authors gratefully acknowledge research support from the Hydrogen Materials—Advanced Research Consortium (HyMARC), established as part of the Energy Materials Network under the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Fuel Cell Technologies Office.

Informed Consent Statement

Not applicable.

Acknowledgments

The work is dedicated to Robert (Bob) Bowman, a tireless and enthusiastic mentor.

Conflicts of Interest

The authors declare no conflict of interest.

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Inorganics 09 00041 g001 550
Figure 1. (a) 11B NMR analysis of Mg(BH4)2, 1 equiv. tetraglyme (G4), 200 °C, 8 h to generate the major product of B12H122−; (b) 11B NMR analysis of Mg(BH4)2, 1 equiv. monoglyme (G1), 200 °C, 8 h to generate the major product of B10H102−.
Figure 1. (a) 11B NMR analysis of Mg(BH4)2, 1 equiv. tetraglyme (G4), 200 °C, 8 h to generate the major product of B12H122−; (b) 11B NMR analysis of Mg(BH4)2, 1 equiv. monoglyme (G1), 200 °C, 8 h to generate the major product of B10H102−.
Inorganics 09 00041 g001
Table
Table 1. Product distribution for the reaction of Mg(BH4)2 with 1.0 equivalent of additive at 180 °C for 8 h.
Table 1. Product distribution for the reaction of Mg(BH4)2 with 1.0 equivalent of additive at 180 °C for 8 h.
EntryAdditiveEquiv.T (°C)B10H102−B12H122−B3H8−UnknownConv aMass Loss% b
1G11.0180291123311.5
2G31.01801025133940.3
3G41.01801927135053.8
4G11.51803714−253
5G1261801630−1763
6G40.2518015 1 16
7G454180−−−−0
8Me-THF1.01803−147
9dodecane1.0180−−−−0
10G11.01607−1310
11G41.0160383519
12G11.02005422361
13G21.0200525517
14G41.0200836111661
15Me-THF1.02002214835
16dodecane1.0200−−−−0
a Characterization of B-containing products were analyzed by 11B NMR spectroscopy using a mix solvent system of 2 D2O: 1 THF. b Thermogravimetric analysis (TGA) (5 K/min ramp, 180 °C), the large mass loss can potentially result from the decomposition of glyme, see Ref. [26]. TGA data for the Mg(BH4)2 with G1, G2, G3, and G4 (Figures S1–S4) are provided in the Supplementary Materials. Abbreviations of Additives: G1 = monoglyme; G2 = diglyme; G3 = triglyme; G4 = tetraglyme; Me-THF = 2-methyltetrahydrofuran. Unknown borane is quartet at -13 ppm in 11B NMR assumed as 1 boron.
Inorganics 09 00041 i001
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Tran, B.L.; Allen, T.N.; Bowden, M.E.; Autrey, T.; Jensen, C.M. Effects of Glymes on the Distribution of Mg(B10H10) and Mg(B12H12) from the Thermolysis of Mg(BH4)2. Inorganics 2021, 9, 41. https://doi.org/10.3390/inorganics9060041

AMA Style

Tran BL, Allen TN, Bowden ME, Autrey T, Jensen CM. Effects of Glymes on the Distribution of Mg(B10H10) and Mg(B12H12) from the Thermolysis of Mg(BH4)2. Inorganics. 2021; 9(6):41. https://doi.org/10.3390/inorganics9060041

Chicago/Turabian Style

Tran, Ba L., Tamara N. Allen, Mark E. Bowden, Tom Autrey, and Craig M. Jensen. 2021. "Effects of Glymes on the Distribution of Mg(B10H10) and Mg(B12H12) from the Thermolysis of Mg(BH4)2" Inorganics 9, no. 6: 41. https://doi.org/10.3390/inorganics9060041

APA Style

Tran, B. L., Allen, T. N., Bowden, M. E., Autrey, T., & Jensen, C. M. (2021). Effects of Glymes on the Distribution of Mg(B10H10) and Mg(B12H12) from the Thermolysis of Mg(BH4)2. Inorganics, 9(6), 41. https://doi.org/10.3390/inorganics9060041

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