A new crystalline form of αβ-d-lactose prepared by oven drying a concentrated aqueous solution of d-lactose

Nicholls, D.; Elleman, C.; Shankland, N.; Shankland, K.

doi:10.1107/S2053229619008210

A new crystalline form of αβ-D-lactose prepared by oven drying a concentrated aqueous solution of D-lactose

D. Nicholls, C. Elleman, N. Shankland and K. Shankland

A new crystalline form of αβ-D-lactose (C₁₂H₂₂O₁₁) has been prepared by the rapid drying of an approximately 40% w/v syrup of D-lactose. Initially identified from its novel powder X-ray diffraction pattern, the monoclinic crystal structure was solved from a microcrystal recovered from the generally polycrystalline mixed-phase residue obtained at the end of the drying step. This is the second crystalline form of αβ-D-lactose to be identified and it has a high degree of structural three-dimensional similarity to the previously identified triclinic form.

Keywords: lactose; crystal structure; powder diffraction; DFT; disaccharide; polymorph.

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Supporting information

	Crystallographic Information File (CIF) https://doi.org/10.1107/S2053229619008210/ky3180sup1.cif Contains datablocks I, global
	Structure factor file (CIF format) https://doi.org/10.1107/S2053229619008210/ky3180Isup2.hkl Contains datablock I
	Portable Document Format (PDF) file https://doi.org/10.1107/S2053229619008210/ky3180sup3.pdf Pawley refinement guidance for refining SX lattice parameters against PXRD data, plus lattice constant comparison table

CCDC reference: 1921562

Computing details top

Data collection: CrysAlis PRO (Rigaku OD, 2019); cell refinement: CrysAlis PRO (Rigaku OD, 2019); data reduction: CrysAlis PRO (Rigaku OD, 2019); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2017 (Sheldrick, 2015b); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).

αβ-D-Lactose top

Crystal data top

C₁₂H₂₂O₁₁	F(000) = 728
M_r = 342.29	D_x = 1.611 Mg m⁻³
Monoclinic, P2₁	Cu Kα radiation, λ = 1.54184 Å
a = 5.0044 (3) Å	Cell parameters from 3068 reflections
b = 38.6364 (14) Å	θ = 4.5–72.2°
c = 7.6007 (4) Å	µ = 1.26 mm⁻¹
β = 106.200 (5)°	T = 100 K
V = 1411.26 (13) Å³	Clear block, colourless
Z = 4	0.08 × 0.02 × 0.02 mm

Data collection top

XtaLAB Synergy Dualflex HyPix diffractometer	3861 independent reflections
Radiation source: micro-focus sealed X-ray tube, PhotonJet (Cu) X-ray Source	3316 reflections with I > 2σ(I)
Mirror monochromator	R_int = 0.057
Detector resolution: 10.0000 pixels mm^-1	θ_max = 67.1°, θ_min = 4.6°
ω scans	h = −5→5
Absorption correction: multi-scan (CrysAlis PRO; Rigaku OD, 2019)	k = −46→41
T_min = 0.804, T_max = 1.000	l = −8→9
8132 measured reflections

Refinement top

Refinement on F²	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F² > 2σ(F²)] = 0.048	w = 1/[σ²(F_o²) + (0.0705P)²] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.120	(Δ/σ)_max < 0.001
S = 1.01	Δρ_max = 0.38 e Å⁻³
3861 reflections	Δρ_min = −0.25 e Å⁻³
431 parameters	Absolute structure: Flack x determined using 989 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons et al., 2013)
2 restraints	Absolute structure parameter: −0.3 (2)
Primary atom site location: dual

Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
O15	1.0019 (7)	0.63348 (8)	0.4404 (5)	0.0179 (7)
O5	0.2846 (7)	0.46940 (8)	0.5118 (5)	0.0194 (7)
O18	0.7775 (7)	0.58691 (8)	0.2858 (5)	0.0169 (7)
O19	1.1446 (7)	0.59577 (9)	0.7705 (5)	0.0205 (8)
H36	1.070821	0.602565	0.847849	0.031*
O4	0.2455 (7)	0.38585 (9)	0.2851 (5)	0.0200 (7)
O21	0.4712 (7)	0.53444 (8)	0.4336 (5)	0.0184 (7)
H40	0.418775	0.516359	0.469732	0.028*
O2	0.5130 (8)	0.41768 (9)	0.9313 (5)	0.0223 (8)
H4	0.620665	0.402031	0.924954	0.034*
O22	0.6082 (7)	0.56071 (10)	−0.0652 (5)	0.0231 (8)
H44	0.466259	0.570697	−0.123045	0.035*
O8	−0.0739 (8)	0.37157 (9)	−0.0756 (5)	0.0232 (8)
H14	−0.012004	0.371203	−0.164754	0.035*
O6	−0.1588 (7)	0.46187 (10)	0.1878 (5)	0.0249 (8)
H11	−0.258564	0.452202	0.097042	0.037*
O1	0.7333 (7)	0.45878 (9)	0.7036 (5)	0.0246 (8)
H2	0.797135	0.478314	0.703099	0.037*
O17	1.5575 (8)	0.70155 (9)	0.7603 (5)	0.0248 (8)
H33	1.429173	0.705620	0.804827	0.037*
O16	1.4840 (8)	0.69894 (9)	0.3686 (5)	0.0238 (8)
O20	0.9133 (7)	0.52636 (9)	0.7562 (5)	0.0208 (7)
H38	0.846224	0.539715	0.816208	0.031*
O13	1.1060 (8)	0.68991 (10)	−0.1138 (5)	0.0258 (8)
H26	0.944059	0.695554	−0.125458	0.039*
O12	1.5346 (9)	0.72657 (10)	0.1161 (6)	0.0299 (9)
H24	1.586499	0.744594	0.172184	0.045*
O3	0.2259 (8)	0.36874 (9)	0.6726 (5)	0.0257 (8)
H6	0.244093	0.351721	0.612530	0.039*
O11	0.2818 (9)	0.28643 (10)	0.6678 (5)	0.0315 (9)
H22	0.150035	0.298206	0.677066	0.047*
O9	−0.1599 (8)	0.30041 (10)	−0.1734 (5)	0.0271 (8)
H16	−0.315580	0.306148	−0.235115	0.041*
O7	0.2127 (8)	0.32976 (9)	0.3684 (5)	0.0246 (8)
O14	0.9488 (8)	0.62845 (9)	0.0366 (5)	0.0243 (8)
H28	0.880367	0.614191	0.091229	0.036*
O10	0.2774 (9)	0.27554 (10)	0.1138 (6)	0.0330 (9)
H18	0.314497	0.255156	0.139478	0.050*
C20	0.9358 (10)	0.58351 (13)	0.6136 (7)	0.0181 (10)
H35	0.750213	0.590714	0.618473	0.022*
C8	0.0534 (11)	0.34525 (13)	0.0480 (8)	0.0205 (11)
H13	0.239621	0.340667	0.035068	0.025*
C24	0.5550 (11)	0.54250 (13)	0.0855 (7)	0.0198 (11)
H42	0.546449	0.517815	0.061304	0.024*
H43	0.377551	0.549730	0.101453	0.024*
C1	0.4517 (10)	0.46096 (14)	0.6919 (7)	0.0213 (11)
H1	0.426733	0.479139	0.775768	0.026*
C23	0.7860 (10)	0.55020 (12)	0.2579 (7)	0.0173 (10)
H41	0.965279	0.544004	0.238128	0.021*
C21	0.9528 (10)	0.54400 (12)	0.6007 (7)	0.0173 (10)
H37	1.140872	0.538424	0.594368	0.021*
C19	0.9984 (10)	0.59750 (12)	0.4411 (7)	0.0170 (10)
H34	1.176610	0.588406	0.431537	0.020*
C6	0.1254 (11)	0.45800 (13)	0.1900 (8)	0.0226 (11)
H9	0.198228	0.480200	0.165561	0.027*
H10	0.138072	0.442088	0.093988	0.027*
C14	1.2288 (11)	0.67893 (13)	0.0680 (7)	0.0209 (11)
H25	1.387599	0.664168	0.066897	0.025*
C17	1.3112 (10)	0.68082 (13)	0.4579 (7)	0.0195 (10)
H30	1.159935	0.696013	0.468979	0.023*
C7	0.0784 (11)	0.35677 (13)	0.2441 (7)	0.0196 (10)
H12	−0.106122	0.361692	0.259024	0.024*
C5	0.3006 (11)	0.44434 (13)	0.3749 (7)	0.0219 (11)
H8	0.494524	0.442104	0.372289	0.026*
C3	0.3540 (11)	0.39801 (13)	0.6144 (7)	0.0218 (11)
H5	0.546689	0.392342	0.619038	0.026*
C13	1.3417 (11)	0.71003 (13)	0.1898 (7)	0.0215 (11)
H23	1.190363	0.725882	0.193211	0.026*
C15	1.0364 (11)	0.65786 (13)	0.1498 (7)	0.0202 (10)
H27	0.872987	0.671902	0.148950	0.024*
C22	0.7497 (10)	0.53044 (13)	0.4241 (7)	0.0170 (10)
H39	0.786548	0.505824	0.410362	0.020*
C2	0.3514 (11)	0.42673 (13)	0.7521 (7)	0.0187 (10)
H3	0.158699	0.429934	0.755627	0.022*
C4	0.1963 (11)	0.40929 (13)	0.4195 (7)	0.0195 (11)
H7	−0.003568	0.410561	0.407681	0.023*
C18	1.4912 (11)	0.67173 (14)	0.6449 (7)	0.0234 (11)
H31	1.395514	0.654941	0.700426	0.028*
H32	1.661968	0.661189	0.634382	0.028*
C16	1.1883 (11)	0.64855 (13)	0.3472 (7)	0.0208 (11)
H29	1.338142	0.632143	0.348393	0.025*
C9	−0.1179 (12)	0.31185 (14)	0.0111 (8)	0.0249 (11)
H15	−0.300892	0.316837	0.028450	0.030*
C10	0.0178 (12)	0.28397 (13)	0.1469 (8)	0.0268 (12)
H17	−0.101628	0.263421	0.128141	0.032*
C11	0.0587 (13)	0.29805 (13)	0.3428 (8)	0.0286 (12)
H19	−0.123605	0.302114	0.363263	0.034*
C12	0.2247 (14)	0.27321 (15)	0.4875 (8)	0.0317 (13)
H20	0.121673	0.251740	0.480278	0.038*
H21	0.399212	0.267975	0.461291	0.038*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O15	0.0173 (17)	0.0172 (16)	0.0209 (18)	−0.0002 (13)	0.0082 (13)	0.0022 (14)
O5	0.0161 (17)	0.0164 (16)	0.024 (2)	0.0003 (13)	0.0020 (14)	−0.0004 (14)
O18	0.0148 (17)	0.0183 (17)	0.0165 (17)	−0.0005 (13)	0.0025 (13)	−0.0011 (14)
O19	0.0222 (19)	0.0210 (17)	0.0166 (18)	−0.0009 (14)	0.0025 (14)	−0.0026 (14)
O4	0.0201 (18)	0.0174 (16)	0.0233 (19)	−0.0019 (14)	0.0077 (14)	−0.0017 (15)
O21	0.0125 (17)	0.0173 (17)	0.027 (2)	−0.0005 (13)	0.0073 (14)	0.0017 (15)
O2	0.023 (2)	0.0237 (19)	0.0196 (19)	0.0007 (14)	0.0043 (15)	0.0013 (15)
O22	0.0196 (17)	0.029 (2)	0.0198 (19)	0.0023 (15)	0.0045 (14)	0.0028 (15)
O8	0.029 (2)	0.0233 (18)	0.0177 (19)	0.0052 (15)	0.0074 (15)	0.0051 (16)
O6	0.0172 (18)	0.029 (2)	0.026 (2)	0.0030 (15)	0.0012 (14)	−0.0057 (16)
O1	0.0186 (18)	0.0229 (18)	0.032 (2)	−0.0011 (14)	0.0059 (15)	0.0012 (17)
O17	0.026 (2)	0.0273 (19)	0.023 (2)	−0.0052 (15)	0.0090 (15)	−0.0036 (16)
O16	0.0262 (19)	0.0230 (19)	0.0212 (19)	−0.0078 (15)	0.0049 (15)	0.0014 (15)
O20	0.0215 (19)	0.0214 (17)	0.0195 (19)	0.0002 (14)	0.0058 (14)	0.0007 (15)
O13	0.0216 (19)	0.032 (2)	0.0235 (19)	−0.0018 (16)	0.0056 (15)	0.0026 (16)
O12	0.035 (2)	0.025 (2)	0.031 (2)	−0.0097 (17)	0.0120 (18)	−0.0032 (17)
O3	0.040 (2)	0.0153 (16)	0.024 (2)	−0.0033 (16)	0.0128 (17)	−0.0002 (15)
O11	0.044 (3)	0.026 (2)	0.025 (2)	0.0022 (17)	0.0102 (18)	0.0042 (17)
O9	0.029 (2)	0.028 (2)	0.0200 (19)	−0.0021 (16)	0.0000 (15)	−0.0044 (16)
O7	0.034 (2)	0.0160 (17)	0.021 (2)	−0.0001 (15)	0.0030 (15)	0.0012 (15)
O14	0.030 (2)	0.0206 (18)	0.023 (2)	−0.0083 (15)	0.0076 (15)	−0.0009 (15)
O10	0.043 (2)	0.0229 (18)	0.034 (2)	0.0112 (17)	0.0104 (18)	0.0000 (17)
C20	0.014 (2)	0.022 (2)	0.016 (2)	−0.0002 (19)	0.0009 (18)	−0.002 (2)
C8	0.020 (3)	0.018 (2)	0.023 (3)	−0.0012 (19)	0.005 (2)	0.001 (2)
C24	0.018 (3)	0.019 (2)	0.021 (3)	0.0002 (18)	0.002 (2)	0.001 (2)
C1	0.013 (2)	0.024 (3)	0.024 (3)	−0.001 (2)	0.000 (2)	0.001 (2)
C23	0.015 (2)	0.019 (2)	0.018 (2)	0.0020 (19)	0.0045 (18)	−0.005 (2)
C21	0.014 (2)	0.021 (3)	0.017 (2)	0.0005 (18)	0.0042 (18)	0.001 (2)
C19	0.017 (3)	0.017 (2)	0.017 (2)	0.0024 (18)	0.0035 (19)	−0.0022 (19)
C6	0.023 (3)	0.020 (2)	0.027 (3)	0.001 (2)	0.010 (2)	0.000 (2)
C14	0.024 (3)	0.018 (2)	0.021 (3)	0.000 (2)	0.007 (2)	0.002 (2)
C17	0.019 (3)	0.022 (3)	0.020 (3)	−0.0018 (19)	0.0090 (19)	0.001 (2)
C7	0.023 (3)	0.016 (2)	0.020 (3)	−0.002 (2)	0.007 (2)	0.001 (2)
C5	0.017 (3)	0.019 (2)	0.029 (3)	0.001 (2)	0.004 (2)	0.002 (2)
C3	0.026 (3)	0.019 (2)	0.022 (3)	0.003 (2)	0.007 (2)	0.001 (2)
C13	0.027 (3)	0.018 (2)	0.020 (3)	−0.001 (2)	0.007 (2)	0.004 (2)
C15	0.022 (3)	0.020 (2)	0.018 (3)	0.001 (2)	0.006 (2)	−0.002 (2)
C22	0.011 (2)	0.018 (2)	0.024 (3)	0.0000 (18)	0.0084 (19)	0.000 (2)
C2	0.016 (3)	0.020 (2)	0.020 (3)	0.0027 (19)	0.0052 (19)	0.002 (2)
C4	0.022 (3)	0.016 (2)	0.018 (3)	−0.0006 (19)	0.0025 (19)	−0.003 (2)
C18	0.025 (3)	0.021 (2)	0.025 (3)	−0.003 (2)	0.008 (2)	0.003 (2)
C16	0.019 (3)	0.019 (2)	0.027 (3)	−0.001 (2)	0.011 (2)	0.001 (2)
C9	0.029 (3)	0.020 (2)	0.025 (3)	−0.001 (2)	0.007 (2)	−0.003 (2)
C10	0.038 (3)	0.017 (3)	0.024 (3)	−0.002 (2)	0.007 (2)	−0.002 (2)
C11	0.043 (3)	0.018 (3)	0.024 (3)	−0.003 (2)	0.009 (2)	0.002 (2)
C12	0.049 (4)	0.023 (3)	0.021 (3)	0.003 (3)	0.007 (2)	0.001 (2)

Geometric parameters (Å, º) top

O15—C19	1.390 (6)	C20—C19	1.529 (7)
O15—C16	1.443 (6)	C8—H13	0.9800
O5—C1	1.428 (6)	C8—C7	1.527 (8)
O5—C5	1.440 (6)	C8—C9	1.531 (7)
O18—C23	1.437 (6)	C24—H42	0.9700
O18—C19	1.433 (6)	C24—H43	0.9700
O19—H36	0.8200	C24—C23	1.515 (7)
O19—C20	1.429 (6)	C1—H1	0.9800
O4—C7	1.383 (6)	C1—C2	1.529 (7)
O4—C4	1.437 (6)	C23—H41	0.9800
O21—H40	0.8200	C23—C22	1.530 (7)
O21—C22	1.424 (6)	C21—H37	0.9800
O2—H4	0.8200	C21—C22	1.532 (7)
O2—C2	1.420 (7)	C19—H34	0.9800
O22—H44	0.8200	C6—H9	0.9700
O22—C24	1.432 (6)	C6—H10	0.9700
O8—H14	0.8200	C6—C5	1.528 (8)
O8—C8	1.410 (6)	C14—H25	0.9800
O6—H11	0.8200	C14—C13	1.526 (7)
O6—C6	1.426 (6)	C14—C15	1.520 (7)
O1—H2	0.8200	C17—H30	0.9800
O1—C1	1.390 (6)	C17—C18	1.497 (7)
O17—H33	0.8200	C17—C16	1.533 (7)
O17—C18	1.430 (7)	C7—H12	0.9800
O16—C17	1.423 (6)	C5—H8	0.9800
O16—C13	1.414 (7)	C5—C4	1.523 (7)
O20—H38	0.8200	C3—H5	0.9800
O20—C21	1.425 (6)	C3—C2	1.528 (7)
O13—H26	0.8200	C3—C4	1.535 (7)
O13—C14	1.411 (7)	C13—H23	0.9800
O12—H24	0.8200	C15—H27	0.9800
O12—C13	1.399 (7)	C15—C16	1.524 (8)
O3—H6	0.8200	C22—H39	0.9800
O3—C3	1.429 (7)	C2—H3	0.9800
O11—H22	0.8200	C4—H7	0.9800
O11—C12	1.415 (7)	C18—H31	0.9700
O9—H16	0.8200	C18—H32	0.9700
O9—C9	1.429 (7)	C16—H29	0.9800
O7—C7	1.442 (6)	C9—H15	0.9800
O7—C11	1.432 (7)	C9—C10	1.515 (8)
O14—H28	0.8200	C10—H17	0.9800
O14—C15	1.419 (6)	C10—C11	1.544 (8)
O10—H18	0.8200	C11—H19	0.9800
O10—C10	1.428 (7)	C11—C12	1.520 (8)
C20—H35	0.9800	C12—H20	0.9700
C20—C21	1.534 (7)	C12—H21	0.9700

C19—O15—C16	114.6 (4)	O4—C7—C8	109.7 (4)
C1—O5—C5	113.8 (4)	O4—C7—H12	110.3
C19—O18—C23	110.8 (3)	O7—C7—C8	108.9 (4)
C20—O19—H36	109.5	O7—C7—H12	110.3
C7—O4—C4	117.3 (4)	C8—C7—H12	110.3
C22—O21—H40	109.5	O5—C5—C6	107.4 (4)
C2—O2—H4	109.5	O5—C5—H8	109.2
C24—O22—H44	109.5	O5—C5—C4	110.2 (4)
C8—O8—H14	109.5	C6—C5—H8	109.2
C6—O6—H11	109.5	C4—C5—C6	111.6 (4)
C1—O1—H2	109.5	C4—C5—H8	109.2
C18—O17—H33	109.5	O3—C3—H5	109.5
C13—O16—C17	113.4 (4)	O3—C3—C2	105.8 (4)
C21—O20—H38	109.5	O3—C3—C4	111.7 (4)
C14—O13—H26	109.5	C2—C3—H5	109.5
C13—O12—H24	109.5	C2—C3—C4	110.8 (4)
C3—O3—H6	109.5	C4—C3—H5	109.5
C12—O11—H22	109.5	O16—C13—C14	110.3 (4)
C9—O9—H16	109.5	O16—C13—H23	110.5
C11—O7—C7	113.3 (4)	O12—C13—O16	107.8 (4)
C15—O14—H28	109.5	O12—C13—C14	107.3 (4)
C10—O10—H18	109.5	O12—C13—H23	110.5
O19—C20—H35	110.8	C14—C13—H23	110.5
O19—C20—C21	110.0 (4)	O14—C15—C14	107.7 (4)
O19—C20—C19	108.7 (4)	O14—C15—H27	108.9
C21—C20—H35	110.8	O14—C15—C16	113.1 (4)
C19—C20—H35	110.8	C14—C15—H27	108.9
C19—C20—C21	105.6 (4)	C14—C15—C16	109.3 (4)
O8—C8—H13	109.2	C16—C15—H27	108.9
O8—C8—C7	109.8 (4)	O21—C22—C23	109.3 (4)
O8—C8—C9	111.1 (4)	O21—C22—C21	109.8 (4)
C7—C8—H13	109.2	O21—C22—H39	109.1
C7—C8—C9	108.3 (4)	C23—C22—C21	110.5 (4)
C9—C8—H13	109.2	C23—C22—H39	109.1
O22—C24—H42	109.8	C21—C22—H39	109.1
O22—C24—H43	109.8	O2—C2—C1	110.7 (4)
O22—C24—C23	109.2 (4)	O2—C2—C3	111.5 (4)
H42—C24—H43	108.3	O2—C2—H3	107.9
C23—C24—H42	109.8	C1—C2—H3	107.9
C23—C24—H43	109.8	C3—C2—C1	110.9 (4)
O5—C1—H1	108.2	C3—C2—H3	107.9
O5—C1—C2	109.3 (4)	O4—C4—C5	105.4 (4)
O1—C1—O5	112.8 (4)	O4—C4—C3	111.3 (4)
O1—C1—H1	108.2	O4—C4—H7	109.8
O1—C1—C2	109.9 (4)	C5—C4—C3	110.6 (4)
C2—C1—H1	108.2	C5—C4—H7	109.8
O18—C23—C24	105.9 (4)	C3—C4—H7	109.8
O18—C23—H41	109.3	O17—C18—C17	111.6 (4)
O18—C23—C22	110.8 (4)	O17—C18—H31	109.3
C24—C23—H41	109.3	O17—C18—H32	109.3
C24—C23—C22	112.2 (4)	C17—C18—H31	109.3
C22—C23—H41	109.3	C17—C18—H32	109.3
O20—C21—C20	113.6 (4)	H31—C18—H32	108.0
O20—C21—H37	107.0	O15—C16—C17	105.9 (4)
O20—C21—C22	110.6 (4)	O15—C16—C15	111.4 (4)
C20—C21—H37	107.0	O15—C16—H29	109.4
C22—C21—C20	111.2 (4)	C17—C16—H29	109.4
C22—C21—H37	107.0	C15—C16—C17	111.2 (4)
O15—C19—O18	106.9 (4)	C15—C16—H29	109.4
O15—C19—C20	111.2 (4)	O9—C9—C8	111.2 (4)
O15—C19—H34	110.2	O9—C9—H15	107.8
O18—C19—C20	108.1 (4)	O9—C9—C10	111.3 (4)
O18—C19—H34	110.2	C8—C9—H15	107.8
C20—C19—H34	110.2	C10—C9—C8	110.6 (4)
O6—C6—H9	109.4	C10—C9—H15	107.8
O6—C6—H10	109.4	O10—C10—C9	107.4 (4)
O6—C6—C5	111.2 (4)	O10—C10—H17	109.7
H9—C6—H10	108.0	O10—C10—C11	111.6 (5)
C5—C6—H9	109.4	C9—C10—H17	109.7
C5—C6—H10	109.4	C9—C10—C11	108.7 (4)
O13—C14—H25	107.4	C11—C10—H17	109.7
O13—C14—C13	110.1 (4)	O7—C11—C10	110.7 (4)
O13—C14—C15	114.1 (4)	O7—C11—H19	109.3
C13—C14—H25	107.4	O7—C11—C12	106.1 (5)
C15—C14—H25	107.4	C10—C11—H19	109.3
C15—C14—C13	110.1 (4)	C12—C11—C10	112.0 (4)
O16—C17—H30	109.5	C12—C11—H19	109.3
O16—C17—C18	106.4 (4)	O11—C12—C11	113.3 (5)
O16—C17—C16	110.0 (4)	O11—C12—H20	108.9
C18—C17—H30	109.5	O11—C12—H21	108.9
C18—C17—C16	111.9 (4)	C11—C12—H20	108.9
C16—C17—H30	109.5	C11—C12—H21	108.9
O4—C7—O7	107.4 (4)	H20—C12—H21	107.7

Reported crystalline forms of D-lactose for which crystal structures are available top

Form	Abbreviation	SpGrp	Z	Z'	T (K)	Refcode	Type	Ref.
α-Lactose monohydrate	α-L.H₂O	P2₁	2	1	150	LACTOS11	SX	Smith et al. (2005)
β-Lactose	β-L	P2₁	2	1	293	BLACTO	SX	Hirotsu & Shimada (1974)
α-Lactose (hygroscopic)	α-LH	P2₁	2	1	293	EYOCUQ	PXRD	Platteau et al. (2004)
α-Lactose (stable anhydrous)	α-LS	P1	2	2	293	EYOCUQ01	PXRD	Platteau et al. (2005)
αβ-lactose	αβ-L_T	P1	2	2	120	LAKKEO01	SX	Guiry et al. (2008)

Notes: SpGrp = space group; refcode = Cambridge Structural Database refcode; SX = structure determined by single-crystal X-ray diffraction; PXRD = structure determined by powder X-ray diffraction.

Sample drying conditions for the lactose syrups top

Sample number	Temperature (°C)	Syrup volume (ml)
1	100	3
2	100	6
3	110	3
4	110	6
5	120	3
6	120	6
7	140	3
8	140	6

Relative abundance of crystalline lactose phases (% w/w) in each of the samples listed in Table 2, as obtained by Rietveld-based QPA top

The estimates are approximate, since the PXRD data had not been collected with the intention of performing QPA; more accurate and precise quantification would require longer data collections over a wider 2θ range.

Sample	αβ-L_M	αβ-L_T	β-L	α-LS	α-L.H₂O
1	0	0	41	0	59
2	0	0	27	0	73
3	57	8	23	12	0
4	80	3	10	7	0
5	81	19	0	0	0
6	91	4	0	5	0
7	90	10	0	0	0
8	92	8	0	0	0

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