The crystal structure of perdeuterated methanol monoammoniate (CD₃OD·ND₃) determined from neutron powder diffraction data at 4.2 and 180 K

The crystal structure of perdeuterated methanol monoammoniate, CD₃OD·ND₃, has been solved from neutron powder diffraction data collected at 4.2 and 180 K. The crystal structure is orthorhombic, space group Pbca (Z = 8), with unit-cell dimensions a = 11.02320 (7), b = 7.66074 (6), c = 7.59129 (6) Å, V = 641.053 (5) ų [ρ_calc = 1162.782 (9) kg m⁻³] at 4.2 K, and a = 11.21169 (5), b = 7.74663 (4), c = 7.68077 (5) Å, V = 667.097 (4) ų [ρ_calc = 1117.386 (7) kg m⁻³] at 180 K. The crystal structure was determined by ab initio methods from the powder data; atomic coordinates and anisotropic displacement parameters were subsequently refined by the Rietveld method to Rp < 3% at both temperatures. The crystal comprises a sheet-like structure in the bc crystallographic plane, consisting of strongly hydrogen bonded elements; these sheets are stacked along the a axis, and adjacent sheets are linked by what may be comparatively weak C—D...O hydrogen bonds. Within the strongly bonded sheet structure, ND₃ molecules are tetrahedrally coordinated by the hydroxy moieties of the methanol molecule, accepting one hydrogen bond (O—D...N) of length ∼1.75 Å, and donating three hydrogen bonds (N—D...O) of length 2.15–2.25 Å. Two of the methyl deuterons appear to participate in weak interlayer hydrogen bonds (C—D...O) of length 2.7–2.8 Å. The hydrogen bonds are ordered at both 4.2 and 180 K. The relative volume change on warming from 4.2 to 180 K, ΔV/V, is +4.06%, which is comparable to, but more nearly isotropic (as determined from the relative change in axial lengths, e.g. Δa/a) than, that observed in deuterated methanol monohydrate.

Computing details

For both compounds, program(s) used to solve structure: FOX, version 1.6.99.

(MEAM_4K_RIETVELD_FIN_phase_1) methanol mono-ammoniate

Crystal data

CD3OD.ND3	V = 641.05 (1) Å^3
Mr = 56.11	Z = 8
Orthorhombic, Pbca	Dx = 1162.8 Mg m^−3
a = 11.02320 (7) Å	Melting point: 218 K
b = 7.66076 (6) Å	T = 4 K
c = 7.59127 (6) Å

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

	x	y	z	Uiso*/Ueq
C	0.26307 (13)	0.04606 (19)	0.2169 (2)	0.01041
O	0.13628 (12)	0.0139 (2)	0.2336 (2)	0.00884
D1	0.28569 (15)	0.1790 (3)	0.2514 (3)	0.03359
D2	0.29373 (19)	0.0183 (3)	0.0841 (3)	0.03927
D3	0.31134 (17)	−0.0414 (3)	0.2996 (3)	0.03227
D4	0.09104 (14)	0.0995 (2)	0.1565 (2)	0.01743
N	0.49051 (11)	0.74662 (18)	1.02666 (14)	0.00925
D5	0.54064 (17)	0.8282 (2)	1.1053 (2)	0.02332
D6	0.44258 (16)	0.8252 (2)	0.9466 (2)	0.02257
D7	0.54772 (18)	0.6783 (2)	0.9513 (2)	0.02285

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C	0.0090 (8)	0.0065 (8)	0.0158 (9)	0.0016 (6)	0.0016 (7)	−0.0010 (5)
O	0.0077 (8)	0.0060 (8)	0.0129 (10)	0.0023 (6)	−0.0015 (7)	0.0013 (6)
D1	0.0203 (11)	0.0243 (11)	0.0561 (14)	−0.0075 (6)	0.0030 (9)	−0.0120 (9)
D2	0.0232 (12)	0.0767 (15)	0.0178 (11)	−0.0042 (10)	0.0105 (8)	−0.0046 (9)
D3	0.0164 (11)	0.0338 (11)	0.0465 (13)	0.0018 (8)	−0.0058 (9)	0.0201 (9)
D4	0.0203 (10)	0.0188 (8)	0.0131 (8)	0.0006 (7)	−0.0012 (7)	0.0036 (6)
N	0.0085 (6)	0.0107 (5)	0.0086 (5)	0.0066 (5)	−0.0009 (5)	0.0008 (5)
D5	0.0257 (11)	0.0243 (9)	0.0199 (10)	−0.0051 (7)	−0.0028 (7)	−0.0083 (7)
D6	0.0270 (9)	0.0231 (9)	0.0176 (8)	−0.0017 (8)	−0.0052 (8)	0.0041 (7)
D7	0.0234 (9)	0.0174 (9)	0.0277 (11)	0.0060 (7)	0.0000 (8)	−0.0023 (8)

Geometric parameters (Å, º)

C—O	1.4248 (19)	D3—D2	1.710 (3)
C—D1	1.080 (2)	D4—C	1.994 (2)
C—D2	1.085 (2)	D4—O	1.011 (2)
C—D3	1.061 (2)	D4—N^i	1.7463 (19)
C—D4	1.994 (2)	N—D4^ii	1.7463 (19)
O—C	1.4248 (19)	N—D5	1.0259 (18)
O—D3	2.038 (2)	N—D6	1.0056 (19)
O—D4	1.011 (2)	N—D7	1.000 (2)
D1—C	1.080 (2)	D5—N	1.0259 (18)
D1—D2	1.771 (3)	D5—D6	1.619 (3)
D1—D3	1.750 (3)	D5—D7	1.641 (2)
D2—C	1.085 (2)	D6—N	1.0056 (19)
D2—D1	1.771 (3)	D6—D5	1.619 (3)
D2—D3	1.710 (3)	D6—D7	1.616 (2)
D3—C	1.061 (2)	D7—N	1.000 (2)
D3—O	2.038 (2)	D7—D5	1.641 (2)
D3—D1	1.750 (3)	D7—D6	1.616 (2)
O—C—D1	111.60 (14)	D2—C—D3	105.7 (2)
O—C—D2	110.74 (18)	C—O—D4	108.68 (17)
O—C—D3	109.28 (17)	D5—N—D6	105.69 (19)
D1—C—D2	109.7 (2)	D5—N—D7	108.20 (19)
D1—C—D3	109.7 (2)	D6—N—D7	107.37 (17)

Symmetry codes: (i) −x+1/2, y−1/2, z−1; (ii) −x+1/2, y+1/2, z+1.

(TEST5_phase_1) methanol mono-ammoniate

Crystal data

CD3OD.ND3	V = 667.10 (1) Å^3
Mr = 56.11	Z = 8
Orthorhombic, Pbca	Dx = 1117.4 Mg m^−3
a = 11.21169 (5) Å	Melting point: 218 K
b = 7.74663 (4) Å	T = 180 K
c = 7.68077 (5) Å

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

	x	y	z	Uiso*/Ueq
C	0.2550 (3)	0.0505 (4)	0.2268 (5)	0.04986
O	0.1338 (2)	0.0133 (4)	0.2297 (4)	0.03407
D1	0.2759 (3)	0.1712 (6)	0.2710 (10)	0.1688
D2	0.2875 (5)	0.0443 (12)	0.1019 (8)	0.1745
D3	0.3003 (3)	−0.0336 (7)	0.2982 (9)	0.13794
D4	0.09216 (19)	0.0980 (4)	0.1593 (4)	0.03985
N	0.49062 (18)	0.7473 (3)	1.0303 (3)	0.03457
D5	0.5415 (3)	0.8274 (4)	1.1076 (4)	0.05101
D6	0.4459 (3)	0.8230 (4)	0.9528 (4)	0.05712
D7	0.5488 (3)	0.6777 (3)	0.9542 (4)	0.05515

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C	0.043 (2)	0.054 (2)	0.054 (2)	−0.0019 (16)	−0.0007 (16)	0.0052 (15)
O	0.0369 (16)	0.0210 (14)	0.044 (2)	−0.0076 (11)	0.0006 (14)	0.0095 (12)
D1	0.057 (3)	0.071 (3)	0.378 (10)	−0.0185 (17)	−0.022 (4)	−0.089 (5)
D2	0.100 (4)	0.338 (10)	0.086 (4)	−0.055 (4)	0.030 (3)	0.017 (4)
D3	0.032 (2)	0.130 (4)	0.252 (7)	0.0179 (17)	−0.035 (3)	0.064 (4)
D4	0.0360 (15)	0.0356 (14)	0.0479 (18)	−0.0036 (10)	0.0095 (11)	0.0033 (11)
N	0.0329 (11)	0.0372 (12)	0.0335 (10)	0.0205 (10)	−0.0036 (10)	0.0045 (10)
D5	0.0628 (18)	0.0590 (18)	0.0313 (16)	−0.0109 (13)	−0.0067 (13)	−0.0023 (12)
D6	0.068 (2)	0.0548 (17)	0.0483 (19)	−0.0236 (15)	−0.0017 (17)	−0.0060 (14)
D7	0.0467 (19)	0.0470 (16)	0.072 (2)	0.0112 (13)	0.0123 (16)	0.0025 (14)

Geometric parameters (Å, º)

C—O	1.390 (4)	D3—O	1.973 (4)
C—D1	1.022 (4)	D3—D1	1.623 (6)
C—D2	1.027 (5)	D3—D2	1.630 (8)
C—D3	0.991 (4)	D4—C	1.933 (4)
C—D4	1.933 (4)	D4—O	0.970 (3)
O—C	1.390 (4)	D4—N^i	1.784 (4)
O—D1	2.033 (4)	N—D4^ii	1.784 (4)
O—D2	1.997 (6)	N—D5	1.031 (3)
O—D3	1.973 (4)	N—D6	0.975 (3)
O—D4	0.970 (3)	N—D7	1.029 (3)
D1—C	1.022 (4)	D5—N	1.031 (3)
D1—O	2.033 (4)	D5—D6	1.602 (4)
D1—D2	1.634 (8)	D5—D7	1.656 (4)
D1—D3	1.623 (6)	D6—N	0.975 (3)
D2—C	1.027 (5)	D6—D5	1.602 (4)
D2—O	1.997 (6)	D6—D7	1.612 (4)
D2—D1	1.634 (8)	D7—N	1.029 (3)
D2—D3	1.630 (8)	D7—D5	1.656 (4)
D3—C	0.991 (4)	D7—D6	1.612 (4)
O—C—D1	114.1 (4)	D2—C—D3	107.8 (7)
O—C—D2	110.6 (4)	C—O—D4	108.8 (3)
O—C—D3	110.8 (3)	D5—N—D6	106.0 (3)
D1—C—D2	105.8 (7)	D5—N—D7	107.0 (3)
D1—C—D3	107.5 (6)	D6—N—D7	107.1 (3)

Symmetry codes: (i) −x+1/2, y−1/2, z−1; (ii) −x+1/2, y+1/2, z+1.