Magnesium perchlorate anhydrate, Mg(ClO₄)₂, from laboratory X-ray powder data

The previously unknown crystal structure of magnesium perchlorate anhydrate, determined and refined from laboratory X-ray powder diffraction data, represents a new structure type. The title compound was obtained by heating magnesium perchlorate hexa­hydrate at 523 K for 2 h under vacuum and it crystallizes in the monoclinic space group P2₁/c. The asymmetric unit contains one Mg (site symmetry on special position 2a), one Cl and four O sites (on general positions 4e). The structure consists of a three-dimensional network resulting from the corner-sharing of MgO₆ octa­hedra and ClO₄ tetra­hedra. Each MgO₆ octa­hedron share corners with six ClO₄ tetra­hedra. Each ClO₄ tetra­hedron shares corners with three MgO₆ octa­hedra, with one O-atom corner dangling. The ClO₄ tetra­hedra are oriented in such a way that one-dimensional channels parallel to [100] are formed between the dangling O atoms.

Computing details

Data collection: COMMANDER (Bruker, 2003); cell refinement: GSAS (Larson & Von Dreele, 2000); data reduction: EVA (Bruker, 2003); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008) and CRYSTALS (Betteridge et al., 2003); program(s) used to refine structure: GSAS (Larson & Von Dreele, 2000); molecular graphics: ATOMS (Dowty, 2000); software used to prepare material for publication: GSAS (Larson & Von Dreele, 2000).

Magnesium bis(perchlorate)

Crystal data

Mg(ClO4)2	Z = 2
Mr = 223.20	F(000) = 222.58
Monoclinic, P21/c	Dx = 2.628 Mg m^−3
Hall symbol: -P 2ybc	Cu Kα1 radiation, λ = 1.5405 Å
a = 4.85705 (10) Å	T = 296 K
b = 8.41719 (16) Å	white
c = 7.87301 (16) Å	flat_sheet, 20 × 20 mm
β = 118.7704 (11)°	Specimen preparation: Prepared at 296 K
V = 282.14 (1) Å^3

Data collection

Bruker D8 Advance diffractometer	Data collection mode: reflection
Radiation source: sealed X-ray tube, Bruker Cu Ceramic X-ray tube	Scan method: step
Ge 111 monochromator	2θmin = 15.0°, 2θmax = 129.989°, 2θstep = 0.017°
Specimen mounting: packed powder

Refinement

Least-squares matrix: full	Profile function: CW Profile function number 4 with 21 terms Pseudovoigt profile coefficients as parameterized in P. Thompson, D. E. Cox & J. B. Hastings (1987). J. Appl. Cryst. 20, 79–83. Asymmetry correction of L. W. Finger, D. E. Cox & A. P. Jephcoat (1994). J. Appl. Cryst. 27, 892–900. Microstrain broadening by P. W. Stephens (1999). J. Appl. Cryst. 32, 281–289. #1(GU) = 14.783 #2(GV) = 23.166 #3(GW) = 12.718 #4(GP) = 1.024 #5(LX) = 5.292 #6(ptec) = 0.00 #7(trns) = 0.00 #8(shft) = -1.9997 #9(sfec) = 0.00 #10(S/L) = 0.0517 #11(H/L) = 0.0011 #12(eta) = 0.7500 #13(S400 ) = 0.0E+00 #14(S040 ) = 0.0E+00 #15(S004 ) = 0.0E+00 #16(S220 ) = 0.0E+00 #17(S202 ) = 0.0E+00 #18(S022 ) = 0.0E+00 #19(S301 ) = 0.0E+00 #20(S103 ) = 0.0E+00 #21(S121 ) = 0.0E+00 Peak tails are ignored where the intensity is below 0.0010 times the peak Aniso. broadening axis 0.0 0.0 1.0
Rp = 0.102	32 parameters
Rwp = 0.145	0 restraints
Rexp = 0.107	0 constraints
RBragg = 0.087	Weighting scheme based on measured s.u.'s
R(F^2) = 0.0875	(Δ/σ)max = 0.04
6894 data points	Background function: GSAS Background function number 1 with 18 terms. Shifted Chebyshev function of 1st kind 1: 48.1453 2: -38.0385 3: 35.2720 4: -29.0981 5: 26.3053 6: -21.8255 7: 18.1473 8: -13.0811 9: 9.91226 10: -7.27175 11: 4.02413 12: -0.768059 13: -0.560606 14: 2.20823 15: -2.95237 16: 3.09518 17: -1.89111 18: 2.06051

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Mg1	0.0	0.0	0.0	0.0144 (10)*
Cl1	0.3101 (5)	0.3330 (2)	0.2442 (3)	0.0164 (4)*
O1	0.2717 (10)	0.1649 (5)	0.2119 (6)	0.0131 (12)*
O2	0.0640 (10)	0.3853 (5)	0.2817 (7)	0.0220 (16)*
O3	0.6143 (9)	0.3493 (5)	0.4192 (6)	0.0219 (15)*
O4	0.3005 (10)	0.4203 (5)	0.0882 (6)	0.0184 (15)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
?	?	?	?	?	?	?

Geometric parameters (Å, º)

Mg1—Cl1	3.322 (2)	Cl1—Mg1^vii	3.281 (2)
Mg1—Cl1^i	3.350 (2)	Cl1—O1	1.434 (4)
Mg1—Cl1^ii	3.281 (2)	Cl1—O2	1.431 (4)
Mg1—Cl1^iii	3.322 (2)	Cl1—O3	1.463 (4)
Mg1—Cl1^iv	3.281 (2)	Cl1—O4	1.412 (5)
Mg1—Cl1^v	3.350 (2)	O1—Mg1	2.081 (4)
Mg1—O1	2.081 (4)	O1—Cl1	1.434 (4)
Mg1—O1^iii	2.081 (4)	O2—Mg1^vi	2.121 (5)
Mg1—O2^i	2.121 (5)	O2—Cl1	1.431 (4)
Mg1—O2^v	2.121 (5)	O3—Mg1^vii	2.092 (4)
Mg1—O3^ii	2.092 (4)	O3—Cl1	1.463 (4)
Mg1—O3^iv	2.092 (4)	O4—Cl1	1.412 (5)
Cl1—Mg1	3.322 (2)	O4—O4^viii	2.889 (8)
Cl1—Mg1^vi	3.350 (2)	O4—O4^ix	3.175 (9)
O1—Mg1—O1^iii	180.0	O2^x—Mg1—O3^ii	93.63 (16)
O1—Mg1—O2^i	86.43 (16)	O2^x—Mg1—O3^xi	86.37 (16)
O1—Mg1—O2^x	93.57 (16)	O3^ii—Mg1—O3^xi	180.0
O1—Mg1—O3^ii	91.78 (17)	O1—Cl1—O2	106.9 (3)
O1—Mg1—O3^xi	88.22 (17)	O1—Cl1—O3	104.2 (3)
O1^iii—Mg1—O2^i	93.57 (16)	O1—Cl1—O4	114.3 (3)
O1^iii—Mg1—O2^x	86.43 (16)	O2—Cl1—O3	110.0 (3)
O1^iii—Mg1—O3^ii	88.22 (17)	O2—Cl1—O4	109.8 (3)
O1^iii—Mg1—O3^xi	91.78 (17)	O3—Cl1—O4	111.5 (3)
O2^i—Mg1—O2^x	179.9657	Mg1—O1—Cl1	141.1 (3)
O2^i—Mg1—O3^ii	86.37 (16)	Mg1^vi—O2—Cl1	140.3 (3)
O2^i—Mg1—O3^xi	93.63 (16)	Mg1^vii—O3—Cl1	133.9 (3)

Symmetry codes: (i) −x, y−1/2, −z+1/2; (ii) −x+1, y−1/2, −z+1/2; (iii) −x, −y, −z; (iv) x−1, −y+1/2, z−1/2; (v) x, −y+1/2, z−1/2; (vi) −x, y+1/2, −z+1/2; (vii) −x+1, y+1/2, −z+1/2; (viii) −x, −y+1, −z; (ix) −x+1, −y+1, −z; (x) x, −y+3/2, z+1/2; (xi) x−1, −y+3/2, z+1/2.