[1] Univ Bristol, Sch Chem, Cantocks Close, Bristol BS8 1TS, Gloucestershire, England
[2] Edith Cowan Univ, Sch Sci, 270 Joondalup Dr, Perth, WA 6027, Australia
[3] Primary Sci Teaching Trust, 12 Whiteladies Rd, Bristol BS8 1PD, Gloucestershire, England
[4] Rhodes Univ, Dept Chem, ZA-6139 Makhanda, South Africa
[5] Univ Western Cape, Dept Chem, Robert Sobukwe Dr, ZA-7535 Bellville, South Africa