Methods and compositions are provided for treatment of an apatite-based resin from which retained solutes have been eluted by an elution buffer that contains an alkali metal salt with solutions of calcium ion, phosphate ion, and hydroxide separately from any sample loading and elution buffers. The treatment solutions restore the resin, reversing the deterioration that is caused by the alkali metal salt in the elution buffer.

Provided is a novel imidic acid compound having a divalent anion useful as a pharmaceutical intermediate, an agrochemical intermediate, an acid catalyst, a battery electrolyte or an antistatic agent. The imidic acid compound is a divalent imidic acid compound represented by the following general formula (1) or (2).

##STR00001##

[In formulae (1) and (2), R.sup.1 to R.sup.3 represent a fluorine atom or an organic groups selected from a linear or branched C1-10 alkoxy group, a C2-10 alkenyloxy group, a C2-10 alkynyloxy group, a C3-10 cycloalkoxy group, a C3-10 cycloalkenyloxy group and a C6-10 aryloxy group, and wherein a fluorine atom, an oxygen atom or an unsaturated bond may also be present in the organic group. M.sup.1 and M.sup.2 represent protons, metal cations or onium cations.]

The present invention provides for a bio-mimetic polymer capable of catalyzing or mineralizing calcium ion and phosphate ions into an apatite.

The present invention provides for a bio-mimetic polymer capable of catalyzing or mineralizing calcium ion and phosphate ions into an apatite.

An oxide includes a compound represented by Formula 1, a compound represented by Formula 2, or a combination thereof:

Li.sub.1−x+y−zTa.sub.2−xM.sub.xP.sub.1−yQ.sub.yO.sub.8−zX.sub.z  Formula 1

wherein, in Formula 1, M is an element having an oxidation number of 5+ or 6+, Q is an element having an oxidation number of 4+, X is a halogen atom, a pseudohalogen, or a combination thereof,
0≤x<0.6, 0≤y<1, and 0≤z<1, wherein x and y are not 0 at the same time,

Li.sub.1−x+yTa.sub.2−xM.sub.xP.sub.1−yQ.sub.yO.sub.8.zLiX  Formula 2

wherein, in Formula 2, M is an element having an oxidation number of 5+ or 6+, Q is an element having an oxidation number of 4+, X is a halogen atom, a pseudohalogen or a combination thereof, 0≤x<0.6, 0≤y<1, and 0≤z<1, wherein x and y are not 0 at the same time, and
wherein in Formulas 1 and 2, M, Q, x, y, and z are independently selected.

An oxide includes a compound represented by Formula 1, a compound represented by Formula 2, or a combination thereof:

Li.sub.1−x+y−zTa.sub.2−xM.sub.xP.sub.1−yQ.sub.yO.sub.8−zX.sub.z  Formula 1

wherein, in Formula 1, M is an element having an oxidation number of 5+ or 6+, Q is an element having an oxidation number of 4+, X is a halogen atom, a pseudohalogen, or a combination thereof,
0≤x<0.6, 0≤y<1, and 0≤z<1, wherein x and y are not 0 at the same time,

Li.sub.1−x+yTa.sub.2−xM.sub.xP.sub.1−yQ.sub.yO.sub.8.zLiX  Formula 2

wherein, in Formula 2, M is an element having an oxidation number of 5+ or 6+, Q is an element having an oxidation number of 4+, X is a halogen atom, a pseudohalogen or a combination thereof, 0≤x<0.6, 0≤y<1, and 0≤z<1, wherein x and y are not 0 at the same time, and
wherein in Formulas 1 and 2, M, Q, x, y, and z are independently selected.

A positive electrode for a sodium ion battery is provided. The positive electrode includes a sodium metal vanadium fluorophosphate having a formula according to Formula I:

Na.sub.3V.sub.2-xM.sub.xO.sub.y(PO.sub.4).sub.2F.sub.3-y  I;

wherein 0<x≤1, 0≤y≤1, and M is one or more additional metals.

A positive electrode for a sodium ion battery is provided. The positive electrode includes a sodium metal vanadium fluorophosphate having a formula according to Formula I:

Na.sub.3V.sub.2-xM.sub.xO.sub.y(PO.sub.4).sub.2F.sub.3-y  I;

wherein 0<x≤1, 0≤y≤1, and M is one or more additional metals.

A method of producing lithium difluorophosphate, the method including: a step of obtaining a first raw material mixture by mixing lithium hexafluorophosphate, at least one selected from the group consisting of an oxide of phosphorus (A) and a lithium salt of a phosphoric acid (B), and a hydrocarbon solvent having from 6 to 12 carbon atoms; a step of obtaining a second raw material mixture by removing at least a part of the hydrocarbon solvent contained in the obtained first raw material mixture; and a step of producing a crude product containing lithium difluorophosphate by reacting the second raw material mixture.

A solid electrolyte including: a compound represented by Formula 1,
Li.sub.xM1.sub.2−yM2.sub.y(PO.sub.4−zX.sub.z).sub.3  Formula 1 wherein, in Formula 1, M1 is a tetravalent element, M2 is a monovalent element, a divalent element, a trivalent element, a tetravalent element, a pentavalent element, a hexavalent element, or a combination thereof, X is a halogen atom, a pseudohalogen, or a combination thereof, 0<x<8, 0≤y<1, and 0<z<4.