Galinstan is the tradename for a liquid metal alloy that is comprised of three elements: gallium (68.5%), indium (21.5%), and tin (10%).1 It behaves a lot like mercury but has significantly lower toxicity. Because of this, Galinstan is used as a replacement for mercury in a variety of applications. For example, Bingxing Wang and coworkers reported how Galinstan can be used in place of mercury in the famous mercury “beating heart” demonstration.2,3
Well, Wang and coworkers are at it again with Galinstan. This time, they report on how liquid blobs of Galinstan can be coaxed to undergo some chemistry that is simultaneously bizarre and beautiful.4 Wait until you check this out (Video 1).
Video 1: Did I Make Venom Using Chemistry?! Tommy Technetium YouTube Channel, September 2, 2024.
Isn’t this some fascinating chemistry? It looks like it’s alive! I was blown away when I saw the octopus-like deformations that occur in the Galinstan droplet when I first got this experiment to work. The convulsing blobs reminded me of a couple of villains: Venom from Spiderman and T1000 in Terminator 2.
By the way, if you try this experiment on your own, I recommend first trying the experiment wherein crystals of copper (II) chloride are added to the Galinstan droplet immersed in a solution of acidified copper (II). This was easier for me to get to work than the experiment where the Galinstan spontaneously deformed when injected into acidified copper solution.
I’m thinking that the easiest way to connect this weird experiment to the chemistry curriculum is to discuss the electrochemistry occurring on the surface of the Galinstan. The authors state that copper nanoparticles are formed on the surface via the reduction of copper (II). Students could be challenged to predict which metals could potentially reduce the copper (II) ions, given the standard reduction potentials of copper (II) and the three metals in Galinstan:
Cu2+(aq) + 2e- → Cu(s) E0 = +0.34 V Equation 1
Ga3+(aq) + 3e- → Ga(l) E0 = -0.53 V Equation 2
In3+(aq) + 3e- → In(l) E0 = -0.34 V Equation 3
Sn2+(aq) + 2e- → Sn(l) E0 = -0.14 V Equation 4
Assuming standard conditions, coupling the oxidation of Ga(l) to the reduction of Cu2+(aq) results in the most thermodynamically favorable reaction:
3 Cu2+(aq) + 2 Ga(l) → 3 Cu(s) + 2 Ga3+(aq) E0 = +0.87 V Equation 5
3 Cu2+(aq) + 2 In(l) → 3 Cu(s) + 2 In3+(aq) E0 = +0.68 V Equation 6
Cu2+(aq) + Sn(l) → Cu(s) + Sn2+(aq) E0 = +0.48 V Equation 7
Nevertheless, the positive cell potential for all three reactions indicates that all three reactions (Equations 5-7) likely occur on the surface of the Galinstan.
I’m curious to hear what the spastic liquid protrusions seen in this experiment bring to your mind. Also, do you have any ideas for how this experiment can be connected to any topics in the chemistry curriculum? Let me know your thoughts in the comments. And as always, if you try this experiment out on your own, let me know about this!!
Happy Experimenting!
References:
- It should be noted that the exact ratio of these three metals in gallium-based liquid alloys of these three metals varies.
- Wang, B.; Jiang, X.; Zhang, Y.; Yu, L.; and Zhang, Y. Journal of Chemical Education 2022, 99 (2), 1095-1099.
- https://www.chemedx.org/blog/my-heart-beats-chemistry
- Wang, B.; Zhang, Y.; Wang, S.; Jiang, X.; Liu, L.; Zhao, D., Journal of Chemical Education 2024, 101. https://pubs.acs.org/doi/epdf/10.1021/acs.jchemed.4c00301
NGSS
Matter and its Interactions help students formulate an answer to the question, “How can one explain the structure, properties, and interactions of matter?” The PS1 Disciplinary Core Idea from the NRC Framework is broken down into three subideas: the structure and properties of matter, chemical reactions, and nuclear processes. Students are expected to develop understanding of the substructure of atoms and to provide more mechanistic explanations of the properties of substances. Chemical reactions, including rates of reactions and energy changes, can be understood by students at this level in terms of the collisions of molecules and the rearrangements of atoms. Students are able to use the periodic table as a tool to explain and predict the properties of elements. Using this expanded knowledge of chemical reactions, students are able to explain important biological and geophysical phenomena. Phenomena involving nuclei are also important to understand, as they explain the formation and abundance of the elements, radioactivity, the release of energy from the sun and other stars, and the generation of nuclear power. Students are also able to apply an understanding of the process of optimization in engineering design to chemical reaction systems. The crosscutting concepts of patterns, energy and matter, and stability and change are called out as organizing concepts for these disciplinary core ideas. In the PS1 performance expectations, students are expected to demonstrate proficiency in developing and using models, planning and conducting investigations, using mathematical thinking, and constructing explanations and designing solutions; and to use these practices to demonstrate understanding of the core ideas.
*More information about this category of NGSS can be found at https://www.nextgenscience.org/dci-arrangement/hs-ps1-matter-and-its-interactions.
"Matter and its Interactions help students formulate an answer to the question, “How can one explain the structure, properties, and interactions of matter?” The PS1 Disciplinary Core Idea from the NRC Framework is broken down into three subideas: the structure and properties of matter, chemical reactions, and nuclear processes. Students are expected to develop understanding of the substructure of atoms and to provide more mechanistic explanations of the properties of substances. Chemical reactions, including rates of reactions and energy changes, can be understood by students at this level in terms of the collisions of molecules and the rearrangements of atoms. Students are able to use the periodic table as a tool to explain and predict the properties of elements. Using this expanded knowledge of chemical reactions, students are able to explain important biological and geophysical phenomena. Phenomena involving nuclei are also important to understand, as they explain the formation and abundance of the elements, radioactivity, the release of energy from the sun and other stars, and the generation of nuclear power. Students are also able to apply an understanding of the process of optimization in engineering design to chemical reaction systems. The crosscutting concepts of patterns, energy and matter, and stability and change are called out as organizing concepts for these disciplinary core ideas. In the PS1 performance expectations, students are expected to demonstrate proficiency in developing and using models, planning and conducting investigations, using mathematical thinking, and constructing explanations and designing solutions; and to use these practices to demonstrate understanding of the core ideas."
Students who demonstrate understanding can construct and revise an explanation for the outcome of a simple chemical reaction based on the outermost electron states of atoms, trends in the periodic table, and knowledge of the patterns of chemical properties.
*More information about all DCI for HS-PS1 can be found at https://www.nextgenscience.org/dci-arrangement/hs-ps1-matter-and-its-interactions and further resources at https://www.nextgenscience.org.
Students who demonstrate understanding can construct and revise an explanation for the outcome of a simple chemical reaction based on the outermost electron states of atoms, trends in the periodic table, and knowledge of the patterns of chemical properties.
Assessment is limited to chemical reactions involving main group elements and combustion reactions.
Examples of chemical reactions could include the reaction of sodium and chlorine, of carbon and oxygen, or of carbon and hydrogen.