Homogeneous and heterogeneous mixtures settle, or separate. As a homogeneous mixture, a solution has one phase (liquid) although the solute and solvent can vary: for example, salt water. Air can be more specifically described as a gaseous solution (oxygen and other gases dissolved in the major component, nitrogen). Since interactions between molecules play almost no role, dilute gases form rather trivial solutions. In part of the literature, they are not even classified as solutions. In gas intermolecular space is greatest and intermolecular force of attraction is least. In chemistry, a mixture is a substance containing two or more elements or compounds that are not
Phomoxanthone A PXA and PXB were discovered in 2001, and their preparation by isolation from "Phomopsis" fungal cultures was described in the corresponding publication. Briefly, a MeOH extract of a "Phomopsis" culture is mixed with HO and washed with hexane. The aqueous phase is then dried and the residue is dissolved in EtOAc, washed with HO, concentrated and repeatedly purified by size-exclusion chromatography. The resulting mixture of PXA and PXB is separated by HPLC. A modified method, in which the initial extraction is done with EtOAc instead of MeOH and the drying step is skipped, was described in 2013. Phomoxanthone A was