Mixed-anion compounds, heteroanionic materials or mixed-anion materials are chemical compounds containing cations and more than one kind of anion. The compounds contain a single phase, rather than just a mixture.[1][2]
Many of the non-metals that could make mixed-anion compounds may have greatly varying volatilities. This makes it more difficult to combine the elements together. Compounds may be produced in a solid state reaction, by heating solids together, either in a vacuum or a gas. Common gases used include, oxygen, hydrogen, ammonia, chlorine, fluorine, hydrogen sulfide, or carbon disulfide. Soft chemical approaches to manufacture include solvothermal synthesis, or substituting atoms in a structure by others, including by water, oxygen, fluorine, or nitrogen. Teflon pouches can be used to separate different formulations. Thin film deposits can yield strained layers. High pressures can be used to prevent evaporation of volatiles. High pressure can result in different crystal forms, perhaps with higher coordination number.[1]
^Sun, Jun; Abudouwufu, Tushagu; Jin, Congcong; Guo, Zhiyong; Zhang, Min (17 December 2021). "K 6 (IO 6 H 4)(HI 2 O 6)(HIO 3) 2 (IO 3) 4 ·2H 2 O: A Case of Iodate with Coexisting [I 5+ O 3] and [I 7+ O 6] Units". Inorganic Chemistry. 61 (1): 688–692. doi:10.1021/acs.inorgchem.1c03436. PMID34919392. S2CID245278633.
^Shlyapnikov, Igor M.; Goreshnik, Evgeny A.; Mazej, Zoran (31 December 2018). "Guanidinium Perfluoridotitanate(IV) Compounds: Structural Determination of an Oligomeric [Ti6F27]3– Anion, and an Example of a Mixed-Anion Salt Containing Two Different Fluoridotitanate(IV) Anions". European Journal of Inorganic Chemistry. 2018 (48): 5246–5257. doi:10.1002/ejic.201801207. S2CID104344701.