Crystal of cyclic phosphonic acid sodium salt and method for manufacturing same

1. A method for producing a crystal of phosphonic acid sodium salt (2ccPA) represented by formula (1):

the method comprising

step (H) of reacting a cyclic phosphonic acid ester represented by formula (9):

wherein R 1 represents alkyl, arylalkyl, or aryl with a sodium halide in an organic solvent to obtain 2ccPA, and

step (I) of concentrating a solution containing the 2ccPA obtained in step (H) under reduced pressure, or cooling the solution containing the 2ccPA obtained in step (H) to precipitate the crystal.

2. The method according to claim 1 , wherein the crystal has an X-ray powder diffraction spectrum comprising a expressed in degrees 2θ at 15° to 17°.

3. The method according to claim 1 , wherein the crystal has an X-ray powder diffraction spectrum comprising a peak expressed in degrees 2θ at 9° to 10°.

4. The method according to claim 1 , wherein the crystal has X-ray powder diffraction spectrum comprising peaks expressed in degrees 2θ at 3° to 5°.

5. The method according to claim 1 , wherein the crystal has an X-ray powder diffraction spectrum obtained with monochromated copper radiation of λ=1.54059 Å comprising a peak at lattice spacing (d) of 15.7684 to 16.1724.

6. The method according to claim 1 , wherein the crystal has an X-ray powder diffraction spectrum obtained with monochromated copper radiation of λ=1.54059 Å comprising peaks at the following lattice spacings (d):

15.7684 to 16.1724

9.5425 to 9.6675

4.8282 to 4.9403

4.4802 to 4.8335

4.1641 to 4.2070

3.7263 to 3.8140.

7. The method according to claim 1 , wherein the crystal has an X-ray powder diffraction spectrum obtained with monochromated copper radiation of λ=1.54059 Å with lattice spacing (d) satisfying any one of the requirements (a) to (y):

(a) Lattice spacing (d)

16.1724

9.6675

4.9186

4.8335

4.5164

4.1835

3.7921

(b) Lattice spacing (d)

15.9390

9.5838

4.9294

4.7972

4.4982

4.1913

3.7953

(c) Lattice spacing (d)

15.8817

9.5631

4.9186

4.7869

4.4937

4.1835

3.7794

(d) Lattice spacing (d)

15.8817

9.5631

4.9294

4.7920

4.4982

4.1874

3.8017

(e) Lattice spacing (d)

15.8817

9.5631

4.9186

4.7869

4.4937

4.1874

3.7921

(f) Lattice spacing (d)

15.8248

9.5425

4.9078

4.7920

4.4937

4.1796

3.7762

(g) Lattice spacing (d)

16.0548

9.6046

4.9294

4.8075

4.5073

4.2070

3.7857

(h) Lattice spacing (d)

15.9967

9.6046

4.9349

4.8023

4.5073

4.1913

3.8017

(i) Lattice spacing (d)

15.8817

9.5631

4.9294

4.7920

4.4982

4.1913

3.8017

(j) Lattice spacing (d)

15.9967

9.6046

4.9024

4.8075

4.5027

4.1835

3.7636

(k) Lattice spacing (d)

16.0548

9.6255

4.9403

4.8023

4.5073

4.1992

3.7985

(l) Lattice spacing (d)

16.0548

9.6255

4.9349

4.8075

4.5073

4.1952

3.7857

(m) Lattice spacing (d)

15.9390

9.5631

4.9186

4.7972

4.4982

4.1874

3.7953

(n) Lattice spacing (d)

15.939

9.5838

4.9132

4.7920

4.4937

4.1874

3.7762

(o) Lattice spacing (d)

15.9967

9.6046

4.9024

4.8075

4.4982

4.1719

3.7293

(p) Lattice spacing (d)

16.0548

9.6255

4.9349

4.8075

4.5073

4.1992

3.8145

(q) Lattice spacing (d)

15.7684

9.5425

4.8282

4.4802

4.1757

3.7263

(r) Lattice spacing (d)

15.9390

9.5838

4.9132

4.8023

4.4937

4.1641

3.7730

(s) Lattice spacing (d)

15.9390

9.5838

4.9186

4.7920

4.4937

4.1835

3.7921

(t) Lattice spacing (d)

15.9390

9.5838

4.9240

4.7920

4.4982

4.1874

3.7921

(u) Lattice spacing (d)

16.0548

9.6255

4.9186

4.7920

4.4982

4.1835

3.7985

(v) Lattice spacing (d)

16.0548

9.6255

4.9294

4.7972

4.5073

4.1874

3.7985

(w) Lattice spacing (d)

16.0548

9.6255

4.9186

4.8075

4.4982

4.1835

3.8049

(x) Lattice spacing (d)

15.9967

9.6046

4.9240

4.8023

4.4982

4.1874

3.7985

(y) Lattice spacing (d)

15.9390

9.5838

4.9186

4.7869

4.4937

4.1796

3.7985.

8. The method according to claim 1 , the method further comprising

step (J) of dissolving the crystal obtained in step (I) in water and/or an organic solvent to obtain a solution, and

step (K) of adding a poor solvent to the solution obtained in step (J) to perform recrystallization.