Observation of calcite (10(1)over-bar4) surface by AFM in air and surface structure analysis

Natural calcite single crystal from Chihuahua Mexico was treated at 873 K f or 1.5 h in a furnace and cooled in air. Thirty minutes later it began to c leave spontaneously by residual thermal stress along (10 (1) over bar 4) pl ane in a desiccator. An atomic force microscope (AFM) was used to observe t he cleaved (10 (1) over bar 4) surface structure in air. Atomic scale AFM i mages were obtained for the first time in air, which show the periodicity o f regular atomic arrangement of (10 (1) over bar 4) surface. The lateral li near dimensions of surface parameters from AFM images show a general agreem ent with those obtained from X-ray diffraction measurement for bulk materia l, It was found that there was 0.06 nm difference in height of alternating oxygen atom rows in the BFM images, The difference was considered due to re construction of calcite surface structure under the balance of atomic inter action on the surface in which half of [CO3](2-) rotated by 35.4+/-5.2 degr ees around the C-O bond axis lying in the (10 (1) over bar 4) surface to re ach a small slope with respect to the (10 (1) over bar 4) surface.