[heyhello (OP)]

what are the names of 2 solids that combust when they come into contact
or repel away from each other violently

[evan_au]

Are you looking for "hypergolic" as a generic term, or do you want some examples?

the most common such propellant combination: dinitrogen tetroxide plus hydrazine

https://en.wikipedia.org/wiki/Hypergolic_propellant

[Bored chemist]

Neither hydrazine, nor N2O4 is  solid at ambient temperatures.

[alancalverd]

Not spontaneous at room temperature, but gunpowder and thermite are common examples of solid-to-solid combustion.

[Bored chemist]

In general, reactions between solids are rare because only the bits in contact can actually react.
Gunpowder "works" because teh sulphur melts and because carbon can form a volatile monoxide

I suspect that a mixture of sodium and iodine would ignite, but I don't fancy trying it.

[Deecart]

what are the names of 2 solids that combust when they come into contact
or repel away from each other violently

Antimatter ?

[alancalverd]

Strictly speaking, annihilation is not the same as combustion, but it's a neat suggestion!

[chiralSPO]

Just a reminder not to actually try these, but for the sake of curiosity...

Manganese(VII) oxide and pretty much any organic matter will react quite violently. I believe this would also extend to solids, even at room temperature, though there may be an induction period. (also, for most demonstrations involving Mn₂O₇ the active oxide is synthesized with the aid of sulfuric acid, which is then still wetting the surface, significantly increasing the rate of reaction, especially with carbohydrate solids, like paper, sugar, starch, cotton, etc., but it also might violate the stipulation that the reaction be purely between two solids)

Few solids can undergo fast reactions at ambient temperature because being solid essentially means that it is hard for the atoms to move around, which is precisely what needs to happen for a chemical reaction to happen quickly. (this is usually a good thing) One way around this is to have at least one of the solids have a low melting temperature, and very high heat of reaction (potassium, sodium, white phosphorus, even sulfur). And another way is to use solid molecular compounds with very, very weak chemical bonds (peroxides, ozonides, malozonides, ) though many of these may just spontaneously decompose/detonate on their own even without a reactive partner (definitely DO NOT try this!!!)

For a vigorous reaction to occur between two solids with only incidental contact, they must be inherently very reactive substances, and likely each highly hazardous, even on their own. But if we allow for some energy input (shock, friction, heat, light etc.) then there are many combinations of solids that combust with each other given the input, but not without it (some combinations are so dependable, they are used commercially in matches).

[Bored chemist]

Manganese(VII) oxide

...is a liquid.

[paul cotter]

How about white phosphorus with potassium chlorate (or barium peroxide ) ? Definitely not one I would want to try or even be in the vicinity. Potassium permanganate and ethylene glycol is hypergolic and as erythritol is the simplest solid polyol would this work? As I have both I may just try it.