Polyhydride

For the reducing agent known as Superhydride, see Lithium triethylborohydride.

A polyhydride or superhydride is a compound that contains an abnormally large amount of hydrogen. This can be described as high hydrogen stoichiometry. Examples include iron pentahydride FeH₅, LiH₆, and LiH₇. By contrast, the more well known lithium hydride only has one hydrogen atom.^[1]

Polyhydrides are only known to be stable under high pressure.^[1]

Polyhydrides are important because they can form substances with a very high density of hydrogen. They may resemble the elusive metallic hydrogen, but can be made under lower pressures. One possibility is that they could be superconductors. Hydrogen sulfide under high pressures forms SH₃ units, and can be a superconductor at 203 K (−70 °C) and a pressure of 1.5 million atmospheres.^[1]

Structures

Unit cell diagram showing the structure of NaH₇, which contains H−3 complexes. The coloured balls in the isosurface, plotted at the level of 0.07 electrons*Å⁻³. One of H₂ molecules is bonded to a hydrogen atom in the NaH unit with a bond length of 1.25 Å, forming a H−3 linear anion.

The polyhydrides of alkaline earth and alkali metals contain cage structures. Also hydrogen may be clustered into H⁻, H−3, or H₂ units. Polyhydrides of transition metals may have the hydrogen atoms arranged around the metal atom. Computations suggest that increasing hydrogen levels will reduce the dimensionality of the metal arrangement, so that layers form separated by hydrogen sheets.^[1] The H−3 substructure is linear.^[2]

H+3 would form triangular structures in the hypothetical H₅Cl.^[2]

Compounds

When sodium hydride is compressed with hydrogen, NaH₃ and NaH₇ form. These are formed at 30 GPa and 2,100 K.^[2]

Heating and compressing a metal with ammonia borane avoids using bulky hydrogen, and produces boron nitride as a decomposition product in addition to the polyhydride.^[3]

formula	name	temperature °C	pressure GPa	crystal structure	space group	a Å	b	c	β	cell volume	formulae per unit cell	Tc K	Comment	refs
LiH2	lithium dihydride	27	130											[4]
LiH6	Lithium hexahydride													[1]
LiH7	Lithium heptahydride													[1]
NaH3	sodium trihydride			orthorhombic	Cmcm	3.332 Å	6.354 Å	4.142 Å	90	87.69	4			[2]
NaH7	sodium heptahydride			monoclinic	Cc	6.99	3.597	5.541	69.465	130.5				[2]
CaHx		500	22	double hexagon										[5]
CaHx		600	121											[5]
RbH9-x			10		Cccm									[6]
RbH9-x					Cm
SrH6				pseudo cubic	Pm3m								semiconductor metallize > 220 GPa	[7]
Sr3H13					C2/m									[7]
SrH22			138	triclinic	P1									[7]
BaH12	Barium dodecahydride		75	pseudo cubic		5.43	5.41	5.37		39.48		20K		[8][9]
FeH5	iron pentahydride	1200	66	tetragonal	I4/mmm									[1]
H3S	Sulfur trihydride	25	150	cubic	Im3m							203K		[10]
H3Se	Selenium trihydride		10											[11]
YH4	yttrium tetrahydride	700	160		I4/mmm									[12]
YH6	yttrium hexahydride	700	160		Im-3m							224		[12][13][14]
YH9	yttrium nonahydride	400	237		P63/mmc							243		[12]
CsH7				tetragonal	P4/nmm									[6]
CsH15+x				triclinic	P1									[6]
LaH10	Lanthanum decahydride	1000	170	cubic	Fm3m	5.09	5.09	5.09		132	4	250K		[15][16]
LaH10	Lanthanum decahydride	25	121	Hexagonal	R3m	3.67	3.67	8.83			1			[15]
LaD11	Lanthanum undecahydride	2150	130-160	Tetragonal	P4/nmm							168		[16]
LaH12	Lanthanum dodecahydride			Cubic								insulating		[16]
LaH7	Lanthanum heptahydride	25	109	monoclinic	C2/m	6.44	3.8	3.69	135	63.9	2			[15]
CeH9	Cerium nonahydride		93	hexagonal	P63/mmc	3.711		5.543		33.053		100K		[17]
CeH10	Cerium decahydride				Fm3m							115K		[18]
PrH9	Praseodymium nonahydride		90-140		P63/mmc	3.60		5.47		61.5		55K 9K		[19][20]
PrH9	Praseodymium nonahydride		120		F43m	4.98				124		69K		[19]
NdH4	Neodymium tetrahydride		85-135	tetragonal	I4/mmm	2.8234		5,7808						[21]
NdH7	Neodymium heptahydride		85-135	monoclinic	C2/c	3.3177	6.252	5.707	89.354					[21]
NdH9	Neodymium nonahydride		110-130	hexagonal	P63/mmc	3.458		5.935						[21]
EuH4			50-130		I4/mmm									[22]
Eu8H46		1600	130	cubic	Pm3n	5.865								[22]
EuH9	Europium nonahydride		86-130	cubic	F43m									[22]
EuH9	Europium nonahydride		>130	hexagonal	P63/mmc									[22]
ThH4	Thorium tetrahydride		86		I4/mmm	2.903		4.421		57.23	2			[3]
ThH4	Thorium tetrahydride		88	trigonal	P321	5.500		3.29		86.18				[3]
ThH4	Thorium tetrahydride			orthorhombic	Fmmm									[3]
ThH6	Thorium hexahydride		86-104		Cmc21					32.36				[3]
ThH9	Thorium nonahydride	2100	152	hexagonal	P63/mmc	3.713		5.541		66.20				[3]
ThH10	Thorium decahydride	1800	85-185	cubic	Fm3m	5.29				148.0		161		[3]
ThH10	Thorium decahydride		<85		Immm	5.304	3.287	3.647		74.03				[3]
UH7	Uranium heptahydride	2000	63	fcc	P63/mmc									[23]
UH8	Uranium octahydride	300	1-55	fcc	Fm3m									[23]
UH9	Uranium nonahydride		40-55	fcc	P63/mmc									[23]

Predicted

Using computational chemistry many other polyhydrides are predicted, including LiH₈,^[24] LiH₉,^[25] LiH₁₀,^[25] CsH₃,^[26] KH₅, RbH₅,^[27] RbH₉,^[24] NaH₉, BaH₆,^[27] CaH₆,^[28] MgH₄, MgH₁₂, MgH₁₆,^[29] SrH₄,^[30] SrH₁₀, SrH₁₂,^[24] ScH₄, ScH₆, ScH₈,^[31] YH₄ and YH₆,^[32] YH₂₄, LaH₈, LaH₁₀,^[33] YH₉, LaH₁₁, CeH₈, CeH₉, CeH₁₀,^[34] PrH₈, PrH₉,^[35] ThH₆, ThH₇ and ThH₁₀,^[36] U₂H₁₃, UH₇, UH₈, UH₉,^[23] AlH₅,^[37] GaH₅, InH₅,^[24] SnH₈, SnH₁₂, SnH₁₄,^[38] PbH₈,^[39] SiH₈ (subsequently discovered),^[24] GeH₈,^[40] (although Ge₃H₁₁ may be stable instead)^[41] AsH₈, SbH₄,^[42] BiH₄, BiH₅, BiH₆,^[43] H₃Se,^[44] H₃S,^[45] Te₂H₅, TeH₄,^[46] PoH₄, PoH₆,^[24] H₂F, H₃F,^[24] H₂Cl, H₃Cl, H₅Cl, H₇Cl,^[47] H₂Br, H₃Br, H₄Br, H₅Br, H₅I,^[24] XeH₂, XeH₄.^[48]

Among the transition elements, VH₈ in a C2/m structure around 200 GPa is predicted to have a superconducting transition temperature of 71.4 K. VH₅ in a P6₃/mmm space group has a lower transition temperature.^[49]

Properties

Superconduction

Under suitably high pressures polyhydrides may become superconducting. Characteristics of substances that are predicted to have high superconducting temperatures are a high phonon frequency, which will happen for light elements, and strong bonds. Hydrogen is the lightest and so will have the highest frequency of vibration. Even changing the isotope to deuterium will lower the frequency and lower the transition temperature. Compounds with more hydrogen will resemble the predicted metallic hydrogen. However, superconductors also tend to be substances with high symmetry and also need the electrons not to be locked into molecular subunits, and require large numbers of electrons in states near the Fermi level. There should also be electron-phonon coupling which happens when the electric properties are tied to the mechanical position of the hydrogen atoms.^[35][50][51] The highest superconduction critical temperatures are predicted to be in groups 3 and 3 of the periodic table. Late transitions elements, heavy lanthanides or actinides have extra d- or f-electrons that interfere with superconductivity.^[52]

For example, lithium hexahydride is predicted to lose all electrical resistance below 38 K at a pressure of 150 GPa. The hypothetical LiH₈ has a predicted superconducting transition temperature at 31 K at 200 GPa.^[53] MgH₆ is predicted to have a T_c of 400 K around 300 GPa.^[54] CaH₆ could have a T_c of 260 K at 120 GPa. PH₃ doped H₃S is also predicted to have a transition temperature above the 203 K measured for H₃S (contaminated with solid sulfur).^[55] Rare earth and actinide polyhydrides may also have highish transition temperatures, for example, ThH₁₀ with T_c = 241 K.^[36] UH₈, which can be decompressed to room temperature without decomposition, is predicted to have a transition temperature of 193 K.^[36] AcH₁₀, if it could be ever made, is predicted to superconduct at temperatures over 204 K, and AcH₁₀ would be similarly conducting under lower pressures (150 GPa).^[56]

H₃Se actually is a van der Waals solid with formula 2H₂Se·H₂ with a measured T_c of 105 K under a pressure of 135 GPa.^[11]

Ternary superhydrides

Ternary superhydrides open up the possibility of many more formulas.^[57] For example, Li₂MgH₁₆ may also be superconducting at high temperatures (200 °C).^[58] A compound of lanthanum, boron and hydrogen is speculated to be a "hot" superconductor (550 K).^[59][60] Elements may substitute for others and so modify the properties eg (La,Y)H₆ and (La,Y)H₁₀ can be made to have a slightly higher critical temperature than YH₆ or LaH₁₀.^[61]

See also

• Potassium nonahydridorhenate, stable at ordinary pressures

References

1. Pépin, C. M.; Geneste, G.; Dewaele, A.; Mezouar, M.; Loubeyre, P. (27 July 2017). "Synthesis of FeH5 : A layered structure with atomic hydrogen slabs". Science. 357 (6349): 382–385. Bibcode:2017Sci...357..382P. doi:10.1126/science.aan0961. PMID 28751605.
2. Struzhkin, Viktor V.; Kim, Duck Young; Stavrou, Elissaios; Muramatsu, Takaki; Mao, Ho-kwang; Pickard, Chris J.; Needs, Richard J.; Prakapenka, Vitali B.; Goncharov, Alexander F. (28 July 2016). "Synthesis of sodium polyhydrides at high pressures". Nature Communications. 7: 12267. Bibcode:2016NatCo...712267S. doi:10.1038/ncomms12267. PMC 4974473. PMID 27464650.
3. Semenok, D. V.; Kvashnin, A. G; Ivanova, A. G.; Troayn, I. A.; Oganov, A. R. (2019). "Synthesis of ThH4, ThH6, ThH9 and ThH10 : a route to room-temperature superconductivity". doi:10.13140/RG.2.2.31274.88003. {{cite journal}}: Cite journal requires |journal= (help)
4. Pépin, Charles; Loubeyre, Paul; Occelli, Florent; Dumas, Paul (23 June 2015). "Synthesis of lithium polyhydrides above 130 GPa at 300 K". Proceedings of the National Academy of Sciences. 112 (25): 7673–7676. Bibcode:2015PNAS..112.7673P. doi:10.1073/pnas.1507508112. PMC 4485130. PMID 26056306.
5. Mishra, Ajay Kumar; Ahart, Muhtar; Somayazulu, Maddury; Park, C. Y; Hemley, Russel J (2017-03-13). "Synthesis of Calcium polyhydrides at high pressure and high temperature". Bulletin of the American Physical Society. 62 (4): B35.008. Bibcode:2017APS..MARB35008M.
6. Zhou, Di; Semenok, Dmitrii; Galasso, Michele; Alabarse, Frederico Gil; Sannikov, Denis; Troyan, Ivan A.; Nakamoto, Yuki; Shimizu, Katsuya; Oganov, Artem R. (June 2024). "Raisins in a Hydrogen Pie: Ultrastable Cesium and Rubidium Polyhydrides". Advanced Energy Materials. 14 (23). arXiv:2401.00742. Bibcode:2024AdEnM..1400077Z. doi:10.1002/aenm.202400077. ISSN 1614-6832.
7. Semenok, Dmitrii V.; Chen, Wuhao; Huang, Xiaoli; Zhou, Di; Kruglov, Ivan A.; Mazitov, Arslan B.; Galasso, Michele; Tantardini, Christian; Gonze, Xavier; Kvashnin, Alexander G.; Oganov, Artem R. (2022-06-03). "Sr-Doped Superionic Hydrogen Glass: Synthesis and Properties of SrH 22". Advanced Materials. 34 (27): 2200924. arXiv:2110.15628. Bibcode:2022AdM....3400924S. doi:10.1002/adma.202200924. ISSN 0935-9648. PMID 35451134. S2CID 240288572.
8. chen, Wuhao (April 2020). "High-Pressure Synthesis of Barium Superhydrides: Pseudocubic BaH12". ResearchGate. Retrieved 2020-04-28.
9. Chen, Wuhao; Semenok, Dmitrii V.; Kvashnin, Alexander G.; Huang, Xiaoli; Kruglov, Ivan A.; Galasso, Michele; Song, Hao; Duan, Defang; Goncharov, Alexander F.; Prakapenka, Vitali B.; Oganov, Artem R.; Cui, Tian (December 2021). "Synthesis of molecular metallic barium superhydride: pseudocubic BaH12". Nature Communications. 12 (1): 273. arXiv:2004.12294. Bibcode:2021NatCo..12..273C. doi:10.1038/s41467-020-20103-5. PMC 7801595. PMID 33431840.
10. Shylin, S. I.; Ksenofontov, V.; Troyan, I. A.; Eremets, M. I.; Drozdov, A. P. (September 2015). "Conventional superconductivity at 203 kelvin at high pressures in the sulfur hydride system". Nature. 525 (7567): 73–76. arXiv:1506.08190. Bibcode:2015Natur.525...73D. doi:10.1038/nature14964. ISSN 1476-4687. PMID 26280333. S2CID 4468914.
11. Mishra, A. K.; Somayazulu, M.; Ahart, M.; Karandikar, A.; Hemley, R. J.; Struzhkin, V. (9 March 2018). "Novel Synthesis Route and Observation of Superconductivity in the Se-H System at Extreme Conditions". APS March Meeting Abstracts. 63 (1): X38.008. Bibcode:2018APS..MARX38008M.
12. Kong, P. P.; Minkov, V. S.; Kuzovnikov, M. A.; Besedin, S. P.; Drozdov, A. P.; Mozaffari, S.; Balicas, L.; Balakirev, F. F.; Prakapenka, V. B.; Greenberg, E.; Knyazev, D. A. (2019-09-23). "Superconductivity up to 243 K in yttrium hydrides under high pressure". arXiv:1909.10482 [cond-mat.supr-con].
13. Troyan, I. A.; Semenok, D. V.; Kvashnin, A. G.; Ivanova, A. G.; Prakapenka, V. B.; Greenberg, E.; Gavriliuk, A. G.; Lyubutin, I. S.; Struzhkin, V. V.; Oganov, A. R. (2021). "Anomalous High-Temperature Superconductivity in YH 6". Advanced Materials. 33 (15): e2006832. arXiv:1908.01534. Bibcode:2021AdM....3306832T. doi:10.1002/adma.202006832. ISSN 0935-9648. PMID 33751670. S2CID 219636252.
14. Troyan, Ivan A.; Semenok, Dmitrii V.; Kvashnin, Alexander G.; Sadakov, Andrey V.; Sobolevskiy, Oleg A.; Pudalov, Vladimir M.; Ivanova, Anna G.; Prakapenka, Vitali B.; Greenberg, Eran; Gavriliuk, Alexander G.; Lyubutin, Igor S.; Struzhkin, Viktor V.; Bergara, Aitor; Errea, Ion; Bianco, Raffaello; Calandra, Matteo; Mauri, Francesco; Monacelli, Lorenzo; Akashi, Ryosuke; Oganov, Artem R. (10 March 2021). "Anomalous High-Temperature Superconductivity in YH 6". Advanced Materials. 33 (15): 2006832. arXiv:1908.01534. Bibcode:2021AdM....3306832T. doi:10.1002/adma.202006832. ISSN 0935-9648. PMID 33751670. S2CID 219636252.
15. Geballe, Zachary M.; Liu, Hanyu; Mishra, Ajay K.; Ahart, Muhtar; Somayazulu, Maddury; Meng, Yue; Baldini, Maria; Hemley, Russell J. (15 January 2018). "Synthesis and Stability of Lanthanum Superhydrides". Angewandte Chemie International Edition. 57 (3): 688–692. Bibcode:2018APS..MARX38010G. doi:10.1002/anie.201709970. PMID 29193506.
16. Drozdov, A. P.; Kong, P. P.; Minkov, V. S.; Besedin, S. P.; Kuzovnikov, M. A.; Mozaffari, S.; Balicas, L.; Balakirev, F. F.; Graf, D. E.; Prakapenka, V. B.; Greenberg, E.; Knyazev, D. A.; Tkacz, M.; Eremets, M. I. (22 May 2019). "Superconductivity at 250 K in lanthanum hydride under high pressures". Nature. 569 (7757): 528–531. arXiv:1812.01561. Bibcode:2019Natur.569..528D. doi:10.1038/s41586-019-1201-8. PMID 31118520. S2CID 119231000.
17. Salke, Nilesh P. (May 2018). "Synthesis of clathrate cerium superhydride CeH9 below 100 GPa with atomic hydrogen sublattice". Nature Communications. 10 (1): 4453. arXiv:1805.02060. doi:10.1038/s41467-019-12326-y. PMC 6773858. PMID 31575861.
18. Chen, Wuhao; Semenok, Dmitrii V.; Huang, Xiaoli; Shu, Haiyun; Li, Xin; Duan, Defang; Cui, Tian; Oganov, Artem R. (2021-09-09). "High-Temperature Superconducting Phases in Cerium Superhydride with a T c up to 115 K below a Pressure of 1 Megabar". Physical Review Letters. 127 (11): 117001. arXiv:2101.01315. Bibcode:2021PhRvL.127k7001C. doi:10.1103/PhysRevLett.127.117001. ISSN 0031-9007. PMID 34558917. S2CID 230524009.
19. Zhou, Di; Semenok, Dmitrii; Defang Duan; Xie, Hui; Xiaoli Huang; Wuhao Chen; Li, Xin; Bingbing Liu; Oganov, Artem R (2019). "Superconducting Praseodymium Superhydrides". Unpublished. 6 (9): eaax6849. arXiv:1904.06643. Bibcode:2020SciA....6.6849Z. doi:10.1126/sciadv.aax6849. PMC 7048426. PMID 32158937.
20. Zhou, Di; Semenok, Dmitrii V.; Duan, Defang; Xie, Hui; Chen, Wuhao; Huang, Xiaoli; Li, Xin; Liu, Bingbing; Oganov, Artem R.; Cui, Tian (February 2020). "Superconducting praseodymium superhydrides". Science Advances. 6 (9): eaax6849. arXiv:1904.06643. Bibcode:2020SciA....6.6849Z. doi:10.1126/sciadv.aax6849. ISSN 2375-2548. PMC 7048426. PMID 32158937.
21. Zhou, Di; Semenok, Dmitrii V.; Xie, Hui; Huang, Xiaoli; Duan, Defang; Aperis, Alex; Oppeneer, Peter M.; Galasso, Michele; Kartsev, Alexey I.; Kvashnin, Alexander G.; Oganov, Artem R. (2020-02-12). "High-Pressure Synthesis of Magnetic Neodymium Polyhydrides". Journal of the American Chemical Society. 142 (6): 2803–2811. arXiv:1908.08304. doi:10.1021/jacs.9b10439. ISSN 0002-7863. PMID 31967807. S2CID 201330599.
22. Semenok, Dmitrii V.; Zhou, Di; Kvashnin, Alexander G.; Huang, Xiaoli; Galasso, Michele; Kruglov, Ivan A.; Ivanova, Anna G.; Gavriliuk, Alexander G.; Chen, Wuhao; Tkachenko, Nikolay V.; Boldyrev, Alexander I. (2020-12-09). "Novel Strongly Correlated Europium Superhydrides". The Journal of Physical Chemistry Letters. 12 (1): 32–40. arXiv:2012.05595. doi:10.1021/acs.jpclett.0c03331. ISSN 1948-7185. PMID 33296213. S2CID 228084018.
23. Kruglov, Ivan A.; Kvashnin, Alexander G.; Goncharov, Alexander F.; Oganov, Artem R.; Lobanov, Sergey; Holtgrewe, Nicholas; Yanilkin, Alexey V. (17 August 2017). "High-temperature superconductivity of uranium hydrides at near-ambient conditions". arXiv:1708.05251 [cond-mat.mtrl-sci].
24. Duan, Defang; Liu, Yunxian; Ma, Yanbin; Shao, Ziji; Liu, Bingbing; Cui, Tian (28 April 2016). "Structure and superconductivity of hydrides at high pressures". National Science Review. 4: 121–135. doi:10.1093/nsr/nww029.
25. Chen, Yangmei; Geng, Hua Y.; Yan, Xiaozhen; Sun, Yi; Wu, Qiang; Chen, Xiangrong (2017). "Prediction of Stable Ground-State Lithium Polyhydrides under High Pressures". Inorganic Chemistry. 56 (7): 3867–3874. arXiv:1705.04199. doi:10.1021/acs.inorgchem.6b02709. PMID 28318270. S2CID 21976165.
26. Shamp, Andrew; Hooper, James; Zurek, Eva (3 September 2012). "Compressed Cesium Polyhydrides: Cs+ Sublattices and H3- Three-Connected Nets". Inorganic Chemistry. 51 (17): 9333–9342. doi:10.1021/ic301045v. PMID 22897718.
27. Zurek, Eva (6 June 2016). "Hydrides of the Alkali Metals and Alkaline Earth Metals Under Pressure". Comments on Inorganic Chemistry. 37 (2): 78–98. doi:10.1080/02603594.2016.1196679. S2CID 99251100.
28. Wang, H.; Tse, J. S.; Tanaka, K.; Iitaka, T.; Ma, Y. (6 April 2012). "Superconductive sodalite-like clathrate calcium hydride at high pressures". Proceedings of the National Academy of Sciences. 109 (17): 6463–6466. arXiv:1203.0263. Bibcode:2012PNAS..109.6463W. doi:10.1073/pnas.1118168109. PMC 3340045. PMID 22492976.
29. Lonie, David C.; Hooper, James; Altintas, Bahadir; Zurek, Eva (19 February 2013). "Metallization of magnesium polyhydrides under pressure". Physical Review B. 87 (5): 054107. arXiv:1301.4750. Bibcode:2013PhRvB..87e4107L. doi:10.1103/PhysRevB.87.054107. S2CID 85453835.
30. Hooper, James; Terpstra, Tyson; Shamp, Andrew; Zurek, Eva (27 March 2014). "Composition and Constitution of Compressed Strontium Polyhydrides". The Journal of Physical Chemistry C. 118 (12): 6433–6447. doi:10.1021/jp4125342.
31. Qian, Shifeng (2017). "Theoretical study of stability and superconductivity of". Physical Review B. 96 (9): 094513. Bibcode:2017PhRvB..96i4513Q. doi:10.1103/physrevb.96.094513.
32. Li, Yinwei; Hao, Jian; Liu, Hanyu; Tse, John S.; Wang, Yanchao; Ma, Yanming (5 May 2015). "Pressure-stabilized superconductive yttrium hydrides". Scientific Reports. 5 (1): 9948. doi:10.1038/srep09948. PMC 4419593. PMID 25942452.
33. Liu, Hanyu; Naumov, Ivan I.; Hoffmann, Roald; Ashcroft, N. W.; Hemley, Russell J. (3 July 2017). "Potential high-Tc superconducting lanthanum and yttrium hydrides at high pressure". Proceedings of the National Academy of Sciences. 114 (27): 6990–6995. Bibcode:2017PNAS..114.6990L. doi:10.1073/pnas.1704505114. PMC 5502634. PMID 28630301.
34. Tsuppayakorn-aek, Prutthipong; Pinsook, Udomsilp; Luo, Wei; Ahuja, Rajeev; Bovornratanaraks, Thiti (12 August 2020). "Superconductivity of Superhydride CeH10 under High Pressure". Materials Research Express. 7 (8): 086001. Bibcode:2020MRE.....7h6001T. doi:10.1088/2053-1591/ababc2. S2CID 225379054.
35. Peng, Feng; Sun, Ying; Pickard, Chris J.; Needs, Richard J.; Wu, Qiang; Ma, Yanming (8 September 2017). "Hydrogen Clathrate Structures in Rare Earth Hydrides at High Pressures: Possible Route to Room-Temperature Superconductivity" (PDF). Physical Review Letters. 119 (10): 107001. Bibcode:2017PhRvL.119j7001P. doi:10.1103/PhysRevLett.119.107001. PMID 28949166.
36. Kvashnin, Alexander G.; Semenok, Dmitry V.; Kruglov, Ivan A.; Oganov, Artem R. (November 2017). "High-Temperature Superconductivity in Th-H System at Pressure Conditions". arXiv:1711.00278. doi:10.1021/acsami.8b17100.
37. Hou, Pugeng; Zhao, Xiusong; Tian, Fubo; Li, Da; Duan, Defang; Zhao, Zhonglong; Chu, Binhua; Liu, Bingbing; Cui, Tian (2015). "High pressure structures and superconductivity of AlH3(H2) predicted by first principles". RSC Adv. 5 (7): 5096–5101. Bibcode:2015RSCAd...5.5096H. doi:10.1039/C4RA14990D. S2CID 97440127.
38. Mahdi Davari Esfahani, M.; Wang, Zhenhai; Oganov, Artem R.; Dong, Huafeng; Zhu, Qiang; Wang, Shengnan; Rakitin, Maksim S.; Zhou, Xiang-Feng (11 March 2016). "Superconductivity of novel tin hydrides (Snn Hm) under pressure". Scientific Reports. 6 (1): 22873. arXiv:1512.07604. Bibcode:2016NatSR...622873M. doi:10.1038/srep22873. PMC 4786816. PMID 26964636.
39. Cheng, Ya; Zhang, Chao; Wang, Tingting; Zhong, Guohua; Yang, Chunlei; Chen, Xiao-Jia; Lin, Hai-Qing (12 November 2015). "Pressure-induced superconductivity in H2-containing hydride PbH4(H2)2". Scientific Reports. 5 (1): 16475. Bibcode:2015NatSR...516475C. doi:10.1038/srep16475. PMC 4642309. PMID 26559369.
40. Szcze¸śniak, R.; Szcze¸śniak, D.; Durajski, A.P. (April 2014). "Thermodynamics of the superconducting phase in compressed GeH4(H2)2". Solid State Communications. 184: 6–11. Bibcode:2014SSCom.184....6S. doi:10.1016/j.ssc.2013.12.036.
41. Davari Esfahani, M. Mahdi; Oganov, Artem R.; Niu, Haiyang; Zhang, Jin (10 April 2017). "Superconductivity and unexpected chemistry of germanium hydrides under pressure". Physical Review B. 95 (13): 134506. arXiv:1701.05600. Bibcode:2017PhRvB..95m4506D. doi:10.1103/PhysRevB.95.134506. S2CID 43481894.
42. Fu, Yuhao; Du, Xiangpo; Zhang, Lijun; Peng, Feng; Zhang, Miao; Pickard, Chris J.; Needs, Richard J.; Singh, David J.; Zheng, Weitao; Ma, Yanming (22 March 2016). "High-Pressure Phase Stability and Superconductivity of Pnictogen Hydrides and Chemical Trends for Compressed Hydrides". Chemistry of Materials. 28 (6): 1746–1755. arXiv:1510.04415. doi:10.1021/acs.chemmater.5b04638. S2CID 54571045.
43. Ma, Yanbin; Duan, Defang; Li, Da; Liu, Yunxian; Tian, Fubo; Yu, Hongyu; Xu, Chunhong; Shao, Ziji; Liu, Bingbing; Cui, Tian (17 November 2015). "High-pressure structures and superconductivity of bismuth hydrides". arXiv:1511.05291 [cond-mat.supr-con].
44. Zhang, Shoutao; Wang, Yanchao; Zhang, Jurong; Liu, Hanyu; Zhong, Xin; Song, Hai-Feng; Yang, Guochun; Zhang, Lijun; Ma, Yanming (22 October 2015). "Phase Diagram and High-Temperature Superconductivity of Compressed Selenium Hydrides". Scientific Reports. 5 (1): 15433. arXiv:1502.02607. Bibcode:2015NatSR...515433Z. doi:10.1038/srep15433. PMC 4614537. PMID 26490223.
45. Durajski, Artur P.; Szczęśniak, Radosław (30 June 2017). "First-principles study of superconducting hydrogen sulfide at pressure up to 500 GPa". Scientific Reports. 7 (1): 4473. Bibcode:2017NatSR...7.4473D. doi:10.1038/s41598-017-04714-5. PMC 5493702. PMID 28667259.
46. Zhong, Xin; Wang, Hui; Zhang, Jurong; Liu, Hanyu; Zhang, Shoutao; Song, Hai-Feng; Yang, Guochun; Zhang, Lijun; Ma, Yanming (4 February 2016). "Tellurium Hydrides at High Pressures: High-Temperature Superconductors". Physical Review Letters. 116 (5): 057002. arXiv:1503.00396. Bibcode:2016PhRvL.116e7002Z. doi:10.1103/PhysRevLett.116.057002. PMID 26894729. S2CID 14435357.
47. Duan, Defang; Huang, Xiaoli; Tian, Fubo; Liu, Yunxian; Li, Da; Yu, Hongyu; Liu, Bingbing; Tian, Wenjing; Cui, Tian (12 November 2015). "Predicted Formation of H3+ in Solid Halogen Polyhydrides at High Pressures". The Journal of Physical Chemistry A. 119 (45): 11059–11065. Bibcode:2015JPCA..11911059D. doi:10.1021/acs.jpca.5b08183. PMID 26469181.
48. Yan, Xiaozhen; Chen, Yangmei; Kuang, Xiaoyu; Xiang, Shikai (28 September 2015). "Structure, stability, and superconductivity of new Xe–H compounds under high pressure". The Journal of Chemical Physics. 143 (12): 124310. Bibcode:2015JChPh.143l4310Y. doi:10.1063/1.4931931. PMID 26429014.
49. Li, Xiaofeng; Peng, Feng (2 November 2017). "Superconductivity of Pressure-Stabilized Vanadium Hydrides". Inorganic Chemistry. 56 (22): 13759–13765. doi:10.1021/acs.inorgchem.7b01686. PMID 29094931.
50. Pietronero, Luciano; Boeri, Lilia; Cappelluti, Emmanuele; Ortenzi, Luciano (9 September 2017). "Conventional/unconventional superconductivity in high-pressure hydrides and beyond: insights from theory and perspectives". Quantum Studies: Mathematics and Foundations. 5: 5–21. doi:10.1007/s40509-017-0128-8. hdl:11573/1622515. S2CID 139800480.
51. Pinsook, Udomsilp (July 2020). "In search for near-room-temperature superconducting critical temperature of metal superhydrides under high pressure: A review". Journal of Metals, Materials and Minerals. 30: 31. doi:10.14456/jmmm.2020.18.
52. Semenok, Dmitrii V.; Kruglov, Ivan A.; Savkin, Igor A.; Kvashnin, Alexander G.; Oganov, Artem R. (April 2020). "On Distribution of Superconductivity in Metal Hydrides". Current Opinion in Solid State and Materials Science. 24 (2): 100808. arXiv:1806.00865. Bibcode:2020COSSM..24j0808S. doi:10.1016/j.cossms.2020.100808. S2CID 119433896.
53. Xie, Yu; Li, Quan; Oganov, Artem R.; Wang, Hui (31 January 2014). "Superconductivity of lithium-doped hydrogen under high pressure". Acta Crystallographica Section C. 70 (2): 104–111. doi:10.1107/S2053229613028337. PMID 24508954.
54. Szczȩśniak, R.; Durajski, A. P. (13 July 2016). "Superconductivity well above room temperature in compressed MgH6". Frontiers of Physics. 11 (6): 117406. Bibcode:2016FrPhy..11k7406S. doi:10.1007/s11467-016-0578-1. S2CID 124245616.
55. Eremets, M I; Drozdov, A P (30 November 2016). "High-temperature conventional superconductivity". Physics-Uspekhi. 59 (11): 1154–1160. Bibcode:2016PhyU...59.1154E. doi:10.3367/UFNe.2016.09.037921. S2CID 126290095.
56. Semenok, Dmitrii V; Kvashnin, Alexander G; Kruglov, Ivan A; Oganov, Artem R (2018). "Actinium hydrides AcH₁₀, AcH₁₂, AcH₁₆ as high-temperature conventional superconductors". The Journal of Physical Chemistry Letters. 9 (8): 1920–1926. arXiv:1802.05676. doi:10.1021/acs.jpclett.8b00615. PMID 29589444. S2CID 4620593.
57. Sukmas, Wiwittawin; Tsuppayakorn-aek, Prutthipong; Pinsook, Udomsilp; Bovornratanaraks, Thiti (30 December 2020). "Near-room-temperature superconductivity of Mg/Ca substituted metal hexahydride under pressure". Journal of Alloys and Compounds. 849: 156434. doi:10.1016/j.jallcom.2020.156434. S2CID 225031775.
58. Flores-Livas, José A.; Arita, Ryotaro (26 August 2019). "A Prediction for "Hot" Superconductivity". Physics. 12: 96. Bibcode:2019PhyOJ..12...96F. doi:10.1103/Physics.12.96.
59. Grockowiak, A. D.; Ahart, M.; Helm, T.; Coniglio, W. A.; Kumar, R.; Somayazulu, M.; Meng, Y.; Oliff, M.; Williams, V.; Ashcroft, N. W.; Hemley, R. J.; Tozer, S. W. (2022). "Hot Hydride Superconductivity Above 550 K". Frontiers in Electronic Materials. 2. arXiv:2006.03004. doi:10.3389/femat.2022.837651.
60. Di Cataldo, Simone; von der Linden, Wolfgang; Boeri, Lilia (2021-06-14). "La-$X$-H hydrides: is hot superconductivity possible?". arXiv:2106.07266 [cond-mat.supr-con].
61. Semenok, Dmitrii V.; Troyan, Ivan A.; Ivanova, Anna G.; Kvashnin, Alexander G.; Kruglov, Ivan A.; Hanfland, Michael; Sadakov, Andrey V.; Sobolevskiy, Oleg A.; Pervakov, Kirill S.; Lyubutin, Igor S.; Glazyrin, Konstantin V.; Giordano, Nico; Karimov, Denis N.; Vasiliev, Alexander L.; Akashi, Ryosuke; Pudalov, Vladimir M.; Oganov, Artem R. (July 2021). "Superconductivity at 253 K in lanthanum–yttrium ternary hydrides". Materials Today. 48: 18–28. arXiv:2012.04787. doi:10.1016/j.mattod.2021.03.025. S2CID 228064078.