Register to reply

What does an 2H- in front of a chemical symbol mean? (i.e. 2H-MoX_2)

by maverick_starstrider
Tags: 2hmox2, chemical, symbol
Share this thread:
Apr25-14, 03:45 PM
maverick_starstrider's Avatar
P: 1,164
Title says it all. I'm reading a lot about the transition metal dichalcogenides and I often see something like


What does that 2H- mean? My best guess is that it has something to do with a hexagonal lattice or stacking or something. Anybody know?
Phys.Org News Partner Physics news on
New complex oxides could advance memory devices
'Squid skin' metamaterials project yields vivid color display
Scientists control surface tension to manipulate liquid metals (w/ Video)
Apr26-14, 10:26 PM
P: 184
Yeah, it has to do with stacking. There are several notations, of which I'm most used the ABC one myself. However, I think this is Ramsdell notation, in which H=hexagonal and the number two would signify the number of layers. Hence 2H should correspond to AB stacking, which agrees with the figure here.
Apr27-14, 10:48 PM
P: 145
Indeed, 2H is the hexagonal stacking motif, with two layers per unit cell. Note that this isn't quite ABAB stacking, since one layer is not a simple translation of the other, but rather requires a rotation. 2H should be contrasted with the 3R (rhombohedral) structure, with three layers per unit cell, all simple translations. See here for example.

Register to reply

Related Discussions
Chemical kinetics diagramm -> chemical equation Biology, Chemistry & Other Homework 3
Meaning of a union symbol in front of a set? Set Theory, Logic, Probability, Statistics 2
The probability that symbol j is sent and symbol k is received Precalculus Mathematics Homework 5
Does anyone know the symbol for a vertical subset symbol Latex help Math & Science Software 7
Chemical element and chemical property Introductory Physics Homework 1