There are pure compounds which only exist as solids under certain conditions (of temperature). Such volatile solids sublime easily under room temperature in the lab.
Agree with all comments, one size does not feet all! keep in mind, solid under vacuum + heat can very often be distilled (so they are liquid).... back to solid at RT. Look a DMSO.
it is based on structural orientation and physio-chemical property of the molecule. especially the bond in which the atoms of the compound prefers. eg Water exist as liquid due to its Hydrogen Bond.
The State of a chemical compound depends on its defined molecular structure/orientation, a fixed ratio of atoms and physicochemical traits consisting one type of "building block". For example, pure individual alkaloids are normally white crystalline solid/powder; where as pure Nicotine (an alkaloid) is liquid. Purity of a chemical compound has noting to do with its state; however for a particular compound, it can be a physicochemical indicator of purity.
dear, your isolate can be solid, liquid, semi solid, oily depending upon its physicochemical properties. It can also be a resin. For further conformation, go for mass & NMR spectroscopy.