Editing Francium (section)

==Compounds==
As a result of francium's instability, its salts are only known to a small extent. Francium [[coprecipitation|coprecipitates]] with several caesium [[salt (chemistry)|salts]], such as [[caesium perchlorate]], which results in small amounts of francium perchlorate. This coprecipitation can be used to isolate francium, by adapting the radiocaesium coprecipitation method of [[Lawrence E. Glendenin]] and C. M. Nelson. It will additionally coprecipitate with many other caesium salts, including the [[iodate]], the [[picrate]], the [[tartrate]] (also [[rubidium]] tartrate), the [[chloroplatinate]], and the [[silicotungstate]]. It also coprecipitates with [[silicotungstic acid]], and with [[perchloric acid]], without another alkali metal as a [[carrier (chemistry)|carrier]], which leads to other methods of separation.<ref>{{cite journal |last= Hyde |first= E. K. |title= Radiochemical Methods for the Isolation of Element 87 (Francium) |journal= [[J. Am. Chem. Soc.]] |date= 1952 |volume= 74 |issue= 16 |pages= 4181–4184 |doi= 10.1021/ja01136a066|bibcode= 1952JAChS..74.4181H |hdl= 2027/mdp.39015086483156 |s2cid= 95854270 |hdl-access= free}}</ref><ref name="francrad">E. N K. Hyde ''Radiochemistry of Francium'', Subcommittee on Radiochemistry, National Academy of Sciences-National Research Council; available from the Office of Technical Services, Dept. of Commerce, 1960.</ref>

===Francium perchlorate===
Francium perchlorate is produced by the reaction of [[francium chloride]] and [[sodium perchlorate]]. The francium perchlorate [[coprecipitation|coprecipitates]] with [[caesium perchlorate]].<ref name="francrad" /> This coprecipitation can be used to isolate francium, by adapting the radiocaesium coprecipitation method of [[Lawrence E. Glendenin]] and C. M. Nelson. However, this method is unreliable in separating [[thallium]], which also coprecipitates with caesium.<ref name="francrad" /> Francium perchlorate's [[entropy]] is expected to be 42.7&nbsp;[[Entropy unit|e.u]]<ref name="L&P" /> (178.7 J mol<sup>−1</sup> K<sup>−1</sup>).

===Francium halides===
Francium halides are all soluble in water and are expected to be white solids. They are expected to be produced by the reaction of the corresponding [[halogen]]s. For example, francium chloride would be produced by the reaction of francium and [[chlorine]]. Francium chloride has been studied as a pathway to separate francium from other elements, by using the high [[vapour pressure]] of the compound, although francium fluoride would have a higher vapour pressure.<ref name="L&P" />

===Other compounds===
Francium nitrate, sulfate, hydroxide, carbonate, acetate, and oxalate, are all soluble in water, while the [[iodate]], [[picrate]], [[tartrate]], [[Chloroplatinic acid|chloroplatinate]], and [[silicotungstate]] are insoluble. The insolubility of these compounds are used to extract francium from other radioactive products, such as [[zirconium]], [[niobium]], [[molybdenum]], [[tin]], [[antimony]], the method mentioned in the section above.<ref name="L&P" /> Francium oxide is believed to disproportionate to the peroxide and francium metal.<ref>{{cite report|page=9|id=UCRL-409|url=https://escholarship.org/uc/item/8056g18b|title=Low Mass Francium and Emanation Isotopes of High Alpha Stability|first1=E.&nbsp;K.|last1=Hyde|first2=A.|last2=Ghiorso|author-link2=Albert Ghiorso|first3=G.&nbsp;T.|last3=Seaborg|author-link3=Glenn Seaborg|date=10 Oct 1949|location=Berkeley, CA|institution=[[UC Radiation Laboratory]]}}</ref>  The CsFr molecule is predicted to have the heavier element (francium) at the negative end of the dipole, unlike all known heterodiatomic alkali metal molecules. Francium [[superoxide]] (FrO<sub>2</sub>) is expected to have a more [[covalent]] character than its lighter [[congener (chemistry)|congeners]]; this is attributed to the 6p electrons in francium being more involved in the francium–oxygen bonding.<ref name="Thayer" /> The relativistic destabilisation of the 6p<sub>3/2</sub> spinor may make francium compounds in oxidation states higher than +1 possible, such as [Fr<sup>V</sup>F<sub>6</sub>]<sup>−</sup>; but this has not been experimentally confirmed.<ref>{{cite journal |last1=Cao |first1=Chang-Su |last2=Hu |first2=Han-Shi |last3=Schwarz |first3=W. H. Eugen |last4=Li |first4=Jun |date=2022 |title=Periodic Law of Chemistry Overturns for Superheavy Elements |type=preprint |url=https://chemrxiv.org/engage/chemrxiv/article-details/63730be974b7b6d84cfdda35 |journal=[[ChemRxiv]] |volume= |issue= |pages= |doi=10.26434/chemrxiv-2022-l798p |access-date=16 November 2022}}</ref>