Chromium

Location:  Group 6, Period 4
Atomic Weight:  51.9961
Coordination Number:  6
Chemical Form in Solution:  Cr(H₂O)₆³⁺

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, H₃PO₄. Avoid basic media. Stable with most metals and inorganic anions in acidic media.

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.

Cr Containing Samples (Preparation & Solution):  Metal (soluble in HCl); Oxides / Ores (chrome ore/oxides are very difficult to dissolve. The following procedures A - D are commonly used:

Nickel, iron, copper, or silver crucibles should be used for D. Platinum may be used for A, B, and C; Organic Matrices (ash at 450°C followed by one of the fusion methods above or Sulphuric / hydrogen peroxide acid digestions may be applicable to non oxide containing samples).