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All sourcesNASA NTRSDOE OSTI
NASA NTRS1974

Elemental abundances in meteoritic and terrestrial matter

Major and trace element analyses of over 180 individual chondrules from 12 carbonaceous chondrites are reported, including individual analyses of 60 chondrules from Pueblito de Allende. Siderophile elements in most chondrules are depleted, compared to the whole chondrite. Correlations of Al-Ir and Ir-Sc among chondrules high in Ca and Al were observed. A Cu-Mn correlation was also found for chondrules from some meteorites. No correlation was observed between Au and other siderophile elements (Fe, Ni, Co and Ir). It is suggested that these elemental associations were present in the material from which the chondrules formed. Compositionally, chondrules appear to be a multicomponent mixture of remelted dust. One component displaying an Al-Ir correlation is identified as Allende-type white aggregates. The other components are a material chemically similar to the present matrix and sulfides-plus-metal material. Abundances of the REE (rare earth elements) were measured in ordinary Allende chondrules and were 50% higher than REE abundances in Mokoia chondrules; REE abundances in Ca-Al rich chondrules were similar to REE abundances in Ca-rich white aggregates.

Schmitt, R. A.↗
NASA NTRS1972

Evidence for association between Ir and Al in L chondrites.

The nature of the Al-Ir association was investigated by plotting the whole chondrite abundance of Ir as determined by Mueller et al. (1971), and the Al abundance for the same chondrites. Ten of the 11 L chondrites plotted show a definite positive trend. The results are most consistent with the condensation mechanism of Larimer (1967) and the prediction of Larimer and Anders (1970).

Osborn, T. W.↗
DOE OSTI2020

Materials Data on Al9Ir2 by Materials Project

Al9Ir2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Ir is bonded in a 9-coordinate geometry to nine Al atoms. There are a spread of Ir–Al bond distances ranging from 2.47–2.61 Å. There are five inequivalent Al sites. In the first Al site, Al is bonded in a linear geometry to two equivalent Ir atoms. In the second Al site, Al is bonded in a 2-coordinate geometry to two equivalent Ir atoms. In the third Al site, Al is bonded in a 2-coordinate geometry to two equivalent Ir atoms. In the fourth Al site, Al is bonded in a distorted bent 120 degrees geometry to two equivalent Ir atoms. In the fifth Al site, Al is bonded in a distorted bent 150 degrees geometry to two equivalent Ir atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AlIr by Materials Project

IrAl is Tetraauricupride structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Ir is bonded in a body-centered cubic geometry to eight equivalent Al atoms. All Ir–Al bond lengths are 2.61 Å. Al is bonded in a body-centered cubic geometry to eight equivalent Ir atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Al3Ir by Materials Project

IrAl3 is Sodium arsenide structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Ir is bonded in a 5-coordinate geometry to eleven Al atoms. There are a spread of Ir–Al bond distances ranging from 2.48–2.82 Å. There are two inequivalent Al sites. In the first Al site, Al is bonded in a trigonal planar geometry to three equivalent Ir and six equivalent Al atoms. All Al–Al bond lengths are 2.82 Å. In the second Al site, Al is bonded in a 1-coordinate geometry to four equivalent Ir and seven Al atoms. There are one shorter (2.66 Å) and three longer (2.77 Å) Al–Al bond lengths.

36 MATERIALS SCIENCE↗