Properties of X Element for Sci-Fi Story Writing

[Ogi]

Hi,
in the sci-fi story I'm writing there is a planet rich of carbon-like element(let's name it X element), that must posses this characteristics:
1 - X element common form is stable(non-radioactive) and it's like graphite - soft and with dark metallic shine. while it's hardest allotropic form is unstable crystals that emits radiation - is this possible and how?
2 - some bonds of the X element with other known elements from the real periodic table makes high-temperatures(-10 or -20 degrees celsius) super conductive materials - which of the known elements will be suitable for such bonds?
3 - the life forms on the alien planet are almost all based on the X element(not carbon) - knowing that the X element is similar to the carbon will the alien life look like the Earth life(in my story I have mostly mushrooms, insects, invertebrates, moss and lichens)?

What properties the X element should have in order to suit all the characteristics above, how should I present this element in a scientific plausible way?
Thank you!

 

[mfb]

1 - X element common form is stable(non-radioactive) and it's like graphite - soft and with dark metallic shine. while it's hardest allotropic form is unstable crystals that emits radiation - is this possible and how?

Radioactivity does not depend on the chemical bonds in the material (technically it can influence electron capture but the effect is completely negligible).

2 - some bonds of the X element with other known elements from the real periodic table makes high-temperatures(-10 or -20 degrees celsius) super conductive materials - which of the known elements will be suitable for such bonds?

Such a high critical temperature is the 100-billion-dollar-question of superconductor research. No one knows.

3 - the life forms on the alien planet are almost all based on the X element(not carbon) - knowing that the X element is similar to the carbon will the alien life look like the Earth life(in my story I have mostly mushrooms, insects, invertebrates, moss and lichens)?

The chemical properties of the element won't determine the look of the species.

What properties the X element should have in order to suit all the characteristics above, how should I present this element in a scientific plausible way?

There is exactly one such element (ignoring the radioactivity), and it is called carbon. You'll have to invent your own fictional periodic table if you want something different (but then it sounds like a simple renaming: "it is not carbon, it behaves like carbon in every way but it is called gnufium!").

 

[Czcibor]

I'm afraid that you have a bit too high expectations, and you'd not get an answer that you'd like (so you'd either face a choice between very soft SF or very serious adjustments).

I think I could try to help with part 3:
https://en.wikipedia.org/wiki/Hypothetical_types_of_biochemistry

Alternative idea:
Moderate dose of handwavium with exotic baryon. We have not much idea how would it work, so for a long while all what you'd say would not be against mainstream phisics:
https://en.wikipedia.org/wiki/Exotic_baryon

 

[GTOM]

I'm afraid that you have a bit too high expectations, and you'd not get an answer that you'd like (so you'd either face a choice between very soft SF or very serious adjustments).

I think I could try to help with part 3:
https://en.wikipedia.org/wiki/Hypothetical_types_of_biochemistry

I wrote a not too hard short story, where they find intelligent crystals on Io.
I also wondered about ammonia instead of water, but others said it is very unlikely, since oxygen is so more reactive (and it is a frequent element).

Alternative idea:
Moderate dose of handwavium with exotic baryon. We have not much idea how would it work, so for a long while all what you'd say would not be against mainstream phisics:
https://en.wikipedia.org/wiki/Exotic_baryon

Interesting. :)

 

[Ogi]

looks like I'm expecting too much from this new element, so I'll try to find a good way not to explain why it is super conductive under such high temperatures(-20 C).
I'm also thinking about an extinct race once lived on the planet that could have made those crystals from the X element and because the crystals are artificial their creators might have made them radioactive - does this sound as a good explanation?
About the life forms can I just say that the X element can bound very easy with many elements like carbon does and that is why it is the base of the alien life?

 

[newjerseyrunner]

Is your Element X regular matter or something else? If it's regular matter, a side effect of creatures using it will be an increased weight. We know that the higher you get on the periodic table, the heavier the elements get. We know of all of the stable elements below 130ish, extra elements must either be super heavy elements or something else entirely (dark matter.)

Carbon is the basis for life because it has 4 valence electrons and can bond with almost anything. There are other elements with 4 valence electrons, but they aren't as reactive as carbon, as you increase in mass, the bonding ability decreases. Silicone is the only other element theorized to be able to support life. Your ElementX would almost certainly have to be in column 14 on the periodic table.

 

[mfb]

@newjerseyrunner: the element is silicon, silicone is something different (at least it does contain silicon).

I'm also thinking about an extinct race once lived on the planet that could have made those crystals from the X element and because the crystals are artificial their creators might have made them radioactive - does this sound as a good explanation?

Well, you can make crystals out of radioactive isotopes. I don't see a reason to do so and for most elements it would be extremely expensive to get sufficient quantities of radioactive isotopes, but in general it is possible.

 

[Czcibor]

looks like I'm expecting too much from this new element, so I'll try to find a good way not to explain why it is super conductive under such high temperatures(-20 C).
I'm also thinking about an extinct race once lived on the planet that could have made those crystals from the X element and because the crystals are artificial their creators might have made them radioactive - does this sound as a good explanation?
About the life forms can I just say that the X element can bound very easy with many elements like carbon does and that is why it is the base of the alien life?

OK, go this exotic barion route.

You would have an excuse concerning its origin, instead of wondering how it could appear during the Big Bang, you'd have convinient "the previous race did it". In order to avoid any question why it was created, you'd within a story make it clear that your characters don't really know and have a few contradicting theories / legends. This matter may not be perfectly stable (seems legit, I actually would be worried that in very realistic settings it would be too unstable) - so you have some radioactivity.

 

[Ogi]

The exotic barion sounds like a good solution. I think I need to read and learn more about physics and chemistry, cause I really don't want to sound stupid while explaining the alien element. And maybe the alien race is a good excuse not to dig deep into the nature of the exotic element. Thank you guys, your help and guidance was precious.

 

[Czcibor]

Ogi:

I'd give you one advice concerning SF setting. If you make such very narrow request concerning what you need, than you're almost doomed to get an answer - no ordinary matter behaves as you need for story reasons. The easier route - try to find some weird but real phenomena, and later build on that.

(on my example - I use tidally locked planet with dense atmosphere)

I wrote a not too hard short story, where they find intelligent crystals on Io.
I also wondered about ammonia instead of water, but others said it is very unlikely, since oxygen is so more reactive (and it is a frequent element).

I'm not saying that in ammonia based life would work (scientific answer right now is: don't know :D ). However, this part concerning reactivity does not seem for me like a challenge. I'd be more worried about behaviour of any longer carbon chains under under such low temperatures.