Lattice Parameters of Nine Oxides and Sulfides as a Function of Pressure

Abstract

The lattice parameters of seven oxides and two sulfides have been measured as a function of pressure to several hundred kilobars. FeO, CoO, NiO, MnO, and MnS have the NaCl structure or slight distortions thereof. The data can be fit by a Born—Mayer equation. For FeO, CoO, and NiO the crystal-field stabilization term contributes 5% to 15% of the total attractive pressure. FeS2 (pyrites) has a cubic structure which can be related to the fcc lattice. Its compressibility is much less than MnS and more comparable to the oxides. The binding is appraently covalent. SnO2, MnO2, and TiO2 all have the same tetragonal structure. For SnO2 and MnO2 the c axis actually expands with increasing pressure at low pressure, then passes through a maximum and ultimately contracts. The compressibilities of these two compounds are low at low pressure and increase at pressures beyond the maximum in c. TiO2 behaves more normally. It is apparent that central forces, and therefore ionic binding, contribute little to the cohesion of these crystals.

Compression of ?-MnS (alabandite) and a new high-pressure phase

“…HPP-MnS appeared to have lower than hexagonal symmetry. Clendenen and Drickamer (1966) examined the compression of MnS to 23.0 GPa. A Bridgman-type opposed anvil apparatus was used without a pressure medium and with aluminum as an internal pressure calibrant.…”

“…Working toward this goal, we have experimentally determined the equation-of-state and stability of e-MnS (alabandite) as a function of pressure. The high-pressure behavior of e-MnS was previously studied by Clendenen and Drickamer (1966), * Also affiliated with the James Franck Institute, University of Chicago Wakabayashi et al (1968), Kraft and Grueling (1988), and McCammon (1991), but their results were inconsistent.…”

Elastic, optical, and dielectric properties and their pressure derivatives of rutile‐structure oxides in a modified rigid ion approximation

“…Nagel and O'Keeffe [8] have pointed out that this mode is the transformation mode from the rutile to the CaCl, structure which has actually been identified as a high pressure phase in several rutile-structure fluorides [30]. High [33]. For TiO, the high pressure phase has been identified as the a-PbO, structure [32, 341, and the occurrence of the CaCI, structure in TiO, or SnO, has not been verified.…”

Equations of state of iron sulfide and constraints on the sulfur content of the Earth

“…Previous equation of state studies for pyrite, FeS2, include the early static compression study of Bridgman [1949] to 3 G Pa, a series of ultrasonic measurements on single crystals summarized by Simmons and Wang [1971], static X ray compression data to 27 GPa reported by Clendenen and Drickamer [1966], and, most recently, some shock compression data to 320 GPa [Simakov et al, 1974]. The latter data, which demonstrate polymorphism in FeS• above •30 GPa, are analyzed in parallel with the new data for pyrrhotite to place constraints on the possible sulfur content of the core.…”