Table 1. Crystal structure information for the different polymorphs of C2S obtained by SCXRD or PXRD.
The adjusted setting is provided for further clarity of the crystal structure description of the polymorph phase transitions (Section 3.2.4).
| Standard setting | Adjusted setting | ||||
|---|---|---|---|---|---|
| Polymorph | Crystal system | Lattice parameters | Space group | Lattice parameters | Space group |
| γ | Orthorhombic | a = 11.214 Å | Pnma (a) | a = 5.081 Å | Pcmn (b), (c) |
| b = 6.758 Å | b = 6.778 Å | ||||
| c = 5.076 Å(a) | c = 11.244 Å(b) | ||||
| β | Monoclinic | a = 5.502 Å | P121/n1(d) | a = 5.502 Å | P121/n1(d), (e) |
| b = 6.745 Å | b = 6.745 Å | ||||
| c = 9.297 Å | c = 9.297 Å | ||||
| β = 94.59°(d) | β = 94.59°(d) | ||||
(2a, b, 2c)†
|
Orthorhombic | a = 11.184 Å | Pbcn (f) | a = 11.184 Å | Pcnb (f) Pmnb or Pmnn (g) |
| b = 18.952 Å | b = 6.837 Å | ||||
| c = 6.837 Å(f) | c = 18.952 Å(f) | ||||
|
(a, 3b, c)†
|
Orthorhombic | a = 9.500 Å | Pna21 (h) | a = 5.601 Å | P21 nb (h) Pmnb (i) |
| b = 5.601 Å | b = 20.863 Å | ||||
| c = 20.863 Å(h) | c = 9.500 Å(h) | ||||
|
Orthorhombic | a = 6.767 Å | Pnma (a) | a = 5.519 Å | Pmnb (a), (f), (i) |
| b = 5.519 Å | b = 6.767 Å | ||||
| c = 9.303 Å(a) | c = 9.303 Å(a) | ||||
| α | Hexagonal / triclinic | a = 5.579 Å | P63/mmc (b) | a = 5.579 Å |
P63/mmc
(b)
(j)
|
| c = 7.150 Å(b) | c = 7.150 Å(b) | ||||
References: (a) Mumme et al. (1995 ▸), (b) Udagawa et al. (1980 ▸), (c) Smith et al. (1965 ▸), (d) Jost et al. (1977 ▸), (e) Midgley (1952 ▸), (f) Regourd et al. (1968 ▸), (g) Sarkar (1980 ▸), (h) Il’inets & Bikbau (1990 ▸), (i) Saalfeld (1975 ▸) and (j) Bredig (1950 ▸).
†
The notation in parentheses refers to the extension of the respective unit cell with respect to the unit-cell parameters of
(of the adjusted setting) required to obtain the superstructure.