# In situ high-pressure synchrotron X-ray powder diffraction study of tunnel manganese oxide minerals

## hollandite, romanechite, and todorokite

Gil Chan Hwang, Jeffrey E. Post, Yongjae Lee

Research output: Contribution to journalArticle

2 Citations (Scopus)

### Abstract

In situ high-pressure synchrotron X-ray powder diffraction study of three tunnel manganese oxide minerals (hollandite with 2 × 2 MnO6octahedra tunnels, romanechite with 2 × 3 tunnels, and todorokite with 3 × 3 tunnels) was performed using a diamond anvil cell and nominally penetrating alcohol and water mixture as a pressure-transmitting medium up to ~8 GPa. Bulk moduli (B0)calculated using Murnaghan’s equation of state are inversely proportional to the size of the tunnel, i.e., 134(4) GPa for hollandite (I2/m), 108(2) GPa for romanechite (C2/m), and 67(5) GPa for todorokite (P2/m). On the other hand, axial compressibilities show different elastic anisotropies depending on the size of the tunnel, i.e., $$\beta_{0}^{a}$$β0a(a/a0)=−0.00066(3) GPa−1, $$\beta_{0}^{b}$$β0b (b/b0)=0.00179(8) GPa−1,$$\beta_{0}^{c}$$β0c(c/c0)=0.00637(4) GPa−1[c > b > a]for hollandite;$$\beta_{0}^{a}$$β0a(a/a0)=0.00485(4) GPa−1,$$\beta_{0}^{b}$$β0b (b/b0)=0.0016(1) GPa−1, $$\beta_{0}^{c}$$β0c(c/c0)=0.00199(8) GPa−1[a > c > b] for romanechite; and $$\beta_{0}^{a}$$β0a(a/a0)=0.00826(9)GPa−1,$$\beta_{0}^{b}$$β0b(b/b0)=0.0054(1)GPa−1, $$\beta_{0}^{c}$$β0c(c/c0)=0.00081(8) GPa−1[a > b > c] for todorokite.Overall, the degree of tunnel distortion increases with increasing pressure and correlates with the size of the tunnel, which is evidenced by the gradual increases in the monoclinic β angles up to 3 GPa of 0.62°,0.8°, and 1.15° in hollandite, romanechite, and todorokite, respectively. The compression of tunnel manganese oxides is related to the tunnel distortion and the size of the tunnel.

Original language English 405-411 7 Physics and Chemistry of Minerals 42 5 https://doi.org/10.1007/s00269-014-0731-8 Published - 2015 May 1

### Fingerprint

Oxide minerals
todorokite
Manganese oxide
manganese oxide
Synchrotrons
X ray powder diffraction
Tunnels
tunnel
X-ray diffraction
mineral
in situ
diamond anvil cell
Diamond
bulk modulus
compressibility
Compressibility
Equations of state
equation of state
alcohol
Diamonds

### All Science Journal Classification (ASJC) codes

• Materials Science(all)
• Geochemistry and Petrology

### Cite this

@article{b69e5f72b61a4b138b389014162be8b4,
title = "In situ high-pressure synchrotron X-ray powder diffraction study of tunnel manganese oxide minerals: hollandite, romanechite, and todorokite",
abstract = "In situ high-pressure synchrotron X-ray powder diffraction study of three tunnel manganese oxide minerals (hollandite with 2 × 2 MnO6octahedra tunnels, romanechite with 2 × 3 tunnels, and todorokite with 3 × 3 tunnels) was performed using a diamond anvil cell and nominally penetrating alcohol and water mixture as a pressure-transmitting medium up to ~8 GPa. Bulk moduli (B0)calculated using Murnaghan’s equation of state are inversely proportional to the size of the tunnel, i.e., 134(4) GPa for hollandite (I2/m), 108(2) GPa for romanechite (C2/m), and 67(5) GPa for todorokite (P2/m). On the other hand, axial compressibilities show different elastic anisotropies depending on the size of the tunnel, i.e., $$\beta_{0}^{a}$$β0a(a/a0)=−0.00066(3) GPa−1, $$\beta_{0}^{b}$$β0b (b/b0)=0.00179(8) GPa−1,$$\beta_{0}^{c}$$β0c(c/c0)=0.00637(4) GPa−1[c > b > a]for hollandite;$$\beta_{0}^{a}$$β0a(a/a0)=0.00485(4) GPa−1,$$\beta_{0}^{b}$$β0b (b/b0)=0.0016(1) GPa−1, $$\beta_{0}^{c}$$β0c(c/c0)=0.00199(8) GPa−1[a > c > b] for romanechite; and $$\beta_{0}^{a}$$β0a(a/a0)=0.00826(9)GPa−1,$$\beta_{0}^{b}$$β0b(b/b0)=0.0054(1)GPa−1, $$\beta_{0}^{c}$$β0c(c/c0)=0.00081(8) GPa−1[a > b > c] for todorokite.Overall, the degree of tunnel distortion increases with increasing pressure and correlates with the size of the tunnel, which is evidenced by the gradual increases in the monoclinic β angles up to 3 GPa of 0.62°,0.8°, and 1.15° in hollandite, romanechite, and todorokite, respectively. The compression of tunnel manganese oxides is related to the tunnel distortion and the size of the tunnel.",
author = "Hwang, {Gil Chan} and Post, {Jeffrey E.} and Yongjae Lee",
year = "2015",
month = "5",
day = "1",
doi = "10.1007/s00269-014-0731-8",
language = "English",
volume = "42",
pages = "405--411",
journal = "Physics and Chemistry of Minerals",
issn = "0342-1791",
publisher = "Springer Verlag",
number = "5",

}

In: Physics and Chemistry of Minerals, Vol. 42, No. 5, 01.05.2015, p. 405-411.

Research output: Contribution to journalArticle

TY - JOUR

T1 - In situ high-pressure synchrotron X-ray powder diffraction study of tunnel manganese oxide minerals

T2 - hollandite, romanechite, and todorokite

AU - Hwang, Gil Chan

AU - Post, Jeffrey E.

AU - Lee, Yongjae

PY - 2015/5/1

Y1 - 2015/5/1

N2 - In situ high-pressure synchrotron X-ray powder diffraction study of three tunnel manganese oxide minerals (hollandite with 2 × 2 MnO6octahedra tunnels, romanechite with 2 × 3 tunnels, and todorokite with 3 × 3 tunnels) was performed using a diamond anvil cell and nominally penetrating alcohol and water mixture as a pressure-transmitting medium up to ~8 GPa. Bulk moduli (B0)calculated using Murnaghan’s equation of state are inversely proportional to the size of the tunnel, i.e., 134(4) GPa for hollandite (I2/m), 108(2) GPa for romanechite (C2/m), and 67(5) GPa for todorokite (P2/m). On the other hand, axial compressibilities show different elastic anisotropies depending on the size of the tunnel, i.e., $$\beta_{0}^{a}$$β0a(a/a0)=−0.00066(3) GPa−1, $$\beta_{0}^{b}$$β0b (b/b0)=0.00179(8) GPa−1,$$\beta_{0}^{c}$$β0c(c/c0)=0.00637(4) GPa−1[c > b > a]for hollandite;$$\beta_{0}^{a}$$β0a(a/a0)=0.00485(4) GPa−1,$$\beta_{0}^{b}$$β0b (b/b0)=0.0016(1) GPa−1, $$\beta_{0}^{c}$$β0c(c/c0)=0.00199(8) GPa−1[a > c > b] for romanechite; and $$\beta_{0}^{a}$$β0a(a/a0)=0.00826(9)GPa−1,$$\beta_{0}^{b}$$β0b(b/b0)=0.0054(1)GPa−1, $$\beta_{0}^{c}$$β0c(c/c0)=0.00081(8) GPa−1[a > b > c] for todorokite.Overall, the degree of tunnel distortion increases with increasing pressure and correlates with the size of the tunnel, which is evidenced by the gradual increases in the monoclinic β angles up to 3 GPa of 0.62°,0.8°, and 1.15° in hollandite, romanechite, and todorokite, respectively. The compression of tunnel manganese oxides is related to the tunnel distortion and the size of the tunnel.

AB - In situ high-pressure synchrotron X-ray powder diffraction study of three tunnel manganese oxide minerals (hollandite with 2 × 2 MnO6octahedra tunnels, romanechite with 2 × 3 tunnels, and todorokite with 3 × 3 tunnels) was performed using a diamond anvil cell and nominally penetrating alcohol and water mixture as a pressure-transmitting medium up to ~8 GPa. Bulk moduli (B0)calculated using Murnaghan’s equation of state are inversely proportional to the size of the tunnel, i.e., 134(4) GPa for hollandite (I2/m), 108(2) GPa for romanechite (C2/m), and 67(5) GPa for todorokite (P2/m). On the other hand, axial compressibilities show different elastic anisotropies depending on the size of the tunnel, i.e., $$\beta_{0}^{a}$$β0a(a/a0)=−0.00066(3) GPa−1, $$\beta_{0}^{b}$$β0b (b/b0)=0.00179(8) GPa−1,$$\beta_{0}^{c}$$β0c(c/c0)=0.00637(4) GPa−1[c > b > a]for hollandite;$$\beta_{0}^{a}$$β0a(a/a0)=0.00485(4) GPa−1,$$\beta_{0}^{b}$$β0b (b/b0)=0.0016(1) GPa−1, $$\beta_{0}^{c}$$β0c(c/c0)=0.00199(8) GPa−1[a > c > b] for romanechite; and $$\beta_{0}^{a}$$β0a(a/a0)=0.00826(9)GPa−1,$$\beta_{0}^{b}$$β0b(b/b0)=0.0054(1)GPa−1, $$\beta_{0}^{c}$$β0c(c/c0)=0.00081(8) GPa−1[a > b > c] for todorokite.Overall, the degree of tunnel distortion increases with increasing pressure and correlates with the size of the tunnel, which is evidenced by the gradual increases in the monoclinic β angles up to 3 GPa of 0.62°,0.8°, and 1.15° in hollandite, romanechite, and todorokite, respectively. The compression of tunnel manganese oxides is related to the tunnel distortion and the size of the tunnel.

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