Rhenium

Location:  Group 8, Period 6
Atomic Weight:  190.2
Coordination Number:  4, 6, 7, 8, 9
Chemical Form in Solution:  ReO₄^1-
(coordination numbers in green are observed less frequently)

Storage & Handling:  Keep tightly sealed when not in use. Store and use at 20 ± 4°C. Do not pipet from container. Do not return portions removed for pipetting to container.

Chemical Compatibility:  Stable in HCl, HNO₃, H₂SO₄, HF, and H₃PO₄. Stable with most metals and inorganic anions in acidic media. Mixing higher levels of ReO₄^1- with Ag⁺, Hg₂²⁺, K⁺, NH₄⁺, Cs⁺, Rb⁺, or Tl⁺ will give the corresponding salt (solubilities are 1-12 g/L).

Stability:  2-100 ppb levels stable for months in 1% HNO₃ / LDPE container. 1-10,000 ppm solutions chemically stable for years in 1-5% HNO₃ / LDPE container.

Re Containing Samples (Preparation & Solution):  Metal (soluble in HNO₃); Oxides / Ores (fuse in Pt⁰ with Na₂CO₃). Organic Matrix (all modes of acid attack invite the danger of loss of some volatile perrhenic acid. The use of a reflux condenser should be considered when a wet acid digestion is used such as nitric / perchloric or Sulphuric / peroxide digestions. The preferred approach is to ash the sample in Pt⁰ mixed with Na₂CO₃ starting the ash at 450°C and then increasing the temperature, if necessary, to 900°C to effect a fusion of accompanying alumino-silicates, etc.).