Table 1 Diamond and reported nanosized polymorphs.

From: Twinning of cubic diamond explains reported nanodiamond polymorphs

Name

Cell parameters (nm)

Space group

Diagnostic d spacings (in nm)***

diamond

a = 0.356

Fd-3m

0.206, 0.126, 0.107

h-diamond

a = 0.252 c = 0.412

P63/mmc52

0.218, 0.206, 0.193, 0.150, 0.126, 0.116, 0.109, 0.107

n-diamond

0.356*

Fm-3m49, R-3m53, P42/mmc11

0.206, 0.178, 0.126, 0.107, 0.103

i-diamond bcc phase 9 0.25-i-carbon 49

0.428** 0.319 0.2549

Im-318, Ia-322, P42/mmc11, P21312, P423212

0.303, 0.214, 0.175, 0.152,0.135, 0.124, 0.114, 0.101****

m-diamond 23

a = 0.436, b = 0.251, c = 1.248, b = 90.9°23

Unknown

0.624, 0.312, 0.218, 0.214, 0.208, 0.207, 0.205, 0.180, 0177, 0.165, 0.151, 0.149, 0.1278, 0.109, 0.108, 0.107

  1. Comments:
  2. *Face-centered cubic metals used for TEM grids and in equipment for c-diamond syntheses have almost identical cell dimensions. In particular, Cu was reported from TEM samples containing the YD material36 and we encountered it in a synthetic sample designed to produce n-diamond (Supplementary Fig. 1).
  3. **Vora and Moravec54 reported its cell parameter between 0.396 and 0.428 nm.
  4. ***Reflections absent in Fd-3m diamond are in bold.
  5. ****d-spacings calculated for Im-3 space group with a = 0.428 nm cell dimension.
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